JP7516155B2 - Fluid Control Device - Google Patents

Description

The present invention relates to a fluid control device that controls the flow rate and pressure of a fluid such as gas.

For example, mass flow controllers are used to control the flow rate of gas in semiconductor manufacturing processes. Some conventional mass flow controllers have fluid control devices such as pressure sensors and control valves attached to a block in which an internal flow path is formed. In order to compactly arrange multiple mass flow controllers side by side, the block has an elongated rectangular parallelepiped shape that extends in the longitudinal direction by a predetermined width (see Patent Document 1).

More specifically, the width of the block is set by standards to, for example, 10 mm. In addition, a number of fluid control devices, each with a width roughly equal to the width of the block, are attached in a line in the longitudinal direction to the mounting surface, which is a surface parallel to the longitudinal direction of the block.

In recent years, however, mass flow controllers are not only required to be compact, but also to be capable of handling a larger flow rate than before. The maximum flow rate of a mass flow controller is almost limited by the flow rate that the control valve can handle. For this reason, as shown in Patent Document 2, for example, it is conceivable to form two internal flow paths in parallel in the width direction within a block, and provide a control valve in each internal flow path to roughly double the flow rate that can be handled.

However, although the above configuration can increase the maximum flow rate, it is necessary to line up two fluid control devices such as control valves in the width direction of the block, making it difficult to make the mass flow controller more compact.

Publication No. WO2011/040270 JP 2014-32635 A

The present invention was made to solve all of the above problems at once, and aims to provide a fluid control device that can increase the maximum flow rate compared to conventional devices while keeping the width dimension small.

That is, the fluid control device according to the present invention comprises a block extending in a longitudinal direction with a predetermined width, an internal flow path formed in the block and extending in the longitudinal direction, a first control valve attached to the block, and a second control valve attached to the block downstream of the first control valve, the internal flow path comprising a first outlet flow path connected to a first outlet through which fluid flows out of the first control valve, and a second inlet flow path connected to a second inlet through which fluid flows into the second control valve, and is characterized in that the first outlet flow path and the second inlet flow path are arranged to overlap at one point when the block is seen through in the width direction.

In this way, the first control valve and the second control valve can be arranged side by side along the longitudinal direction, reducing the width of the block and allowing the fluids flowing out of each control valve to merge and flow. Therefore, by using two control valves, the maximum flow rate can be approximately doubled compared to the conventional method while keeping the width of the fluid control device compact.

Even if the width dimension of the block is small, in order to easily arrange the first outflow passage and the second inflow passage in a twisted position without interfering with each other within the block, the block needs to have a mounting surface on which a fluid control device is mounted and a protrusion that protrudes a predetermined amount from the mounting surface, and either the first control valve or the second control valve can be mounted on the mounting surface.

To shorten the length of the internal flow passage formed in the block as much as possible, reduce the internal volume, and improve control responsiveness, the second control valve may be provided on the protruding portion. In this case, when fluid is introduced from the end face or the opposite side to the mounting face of the block, it is easy to shorten the length of the flow passage for flowing the fluid into the first control valve located upstream.

As another aspect for facilitating the arrangement of the first outlet flow passage and the second inlet flow passage in a twisted position while reducing the width dimension of the block, the first control valve includes a first valve block having a first contact surface that contacts the surface of the block, the first inlet through which the fluid flows into the first valve block, and the first outlet through which the fluid flows out of the first valve block open on the first contact surface, and the second control valve includes a second valve block having a second contact surface that contacts the surface of the block, and the second inlet through which the fluid flows into the second valve block, and the second outlet through which the fluid flows out of the second valve block open on the second contact surface. In this case, it is not necessary to arrange the entire control valves outside the block and form recesses or the like for accommodating parts of the control valves within the block. As a result, it is easier to secure space for forming internal flow passages within the block, and the degree of freedom in arranging the first outlet flow passage and the second inlet flow passage can be increased.

A specific example of a configuration that can achieve a large flow rate while remaining compact even when the width dimension of the block is minimized is one in which the first control valve and the second control valve have the same width dimension as the block.

In order to accurately control the total flow rate of the fluid that has passed through the first control valve and the second control valve to a desired value, the internal flow path may further include a post-junction flow path through which the fluid that has passed through the first control valve or the second control valve joins and flows, a second outlet port through which the fluid flows out of the second control valve, and a second outlet flow path that connects the post-junction flow path, the downstream side of the first outlet flow path is connected to the post-junction flow path, and the device may further include a flow sensor that measures the flow rate of the fluid flowing through the post-junction flow path, and a fluid controller that controls at least one of the first control valve or the second control valve based at least on the flow rate measured by the flow sensor.

Another aspect for achieving a desired overall flow rate with each control valve is one in which the internal flow path further comprises a first inlet flow path connected to a first inlet through which fluid flows into the first control valve, and a pre-branch flow path whose downstream side is connected to the first inlet flow path and the second inlet flow path, and further comprises a flow sensor that measures the flow rate of fluid flowing through the pre-branch flow path, and a fluid controller that controls at least one of the first control valve or the second control valve based at least on the flow rate measured by the flow sensor.

In order to accurately achieve the desired large flow rate while preventing the control of the fluid by the first control valve and the second control valve from interfering with each other and degrading control performance, the fluid controller may include an opening control unit that controls the opening of either the first control valve or the second control valve so that a shared target flow rate that is a predetermined multiple smaller than the set flow rate flows, and a flow feedback control unit that controls the other of the first control valve or the second control valve so that the deviation between the set flow rate and the flow rate measured by the flow sensor is small.

For example, in order to enable one control valve to achieve a flow rate close to the shared target flow rate through the control of the aperture control unit even when there is a fluctuation in supply pressure, and to reduce the burden on the other control valve that is flow rate feedback controlled, the aperture control unit may include a target aperture calculation unit that calculates a target aperture corresponding to the shared target flow rate based on the pressure upstream of the first control valve, and a voltage control unit that applies a voltage corresponding to the target aperture to the other of the first control valve or the second control valve.

To achieve approximately the same flow rate in both the first control valve and the second control valve, and thus enable a maximum flow rate of approximately twice the conventional rate for the entire fluid control device, the shared target flow rate may be set to 1/2 the set flow rate.

To achieve the desired overall flow rate from each control valve using a simple control law, the fluid controller needs to be equipped with a synchronization control unit that controls the opening of the first control valve and the opening of the second control valve so that they are synchronized.

To simplify the control law by making both the first and second control valves operate in the same way, while maintaining the flow rate output from the fluid control device at a set flow rate even in the presence of disturbances, the first and second control valves should be of the same type, and the synchronization control unit should apply the same voltage to each of the first and second control valves so as to reduce the deviation from the flow rate measured by the flow sensor.

In order to normally perform flow control using either the first control valve or the second control valve, and to enable self-recovery from an abnormality in the control valve performing flow control by switching flow control to another control valve, the fluid controller may include a flow feedback control unit that controls either the first control valve or the second control valve so that the deviation between the set flow rate and the flow rate measured by the flow sensor is small, a valve abnormality detection unit that detects an abnormality in the first control valve or the second control valve, and a control target switching unit that switches the control valve to be controlled by the flow feedback control unit when the valve abnormality detection unit detects an abnormality in the first control valve or the second control valve controlled by the flow feedback control unit.

With such a system, if an abnormality occurs in the control valve controlling the flow rate, another control valve is automatically switched over to continue flow rate control, without the operator having to perform any special resetting or repairing operations. Therefore, with such a fluid control device, even if one of the control valves breaks down, self-recovery and self-repair are possible, improving the reliability of flow rate control. Furthermore, for example, if the first control valve and the second control valve are of the normally open type, even if the control valve that initially controlled the flow rate breaks down, that control valve will be in a fully open state, and will not be likely to interfere with flow rate control by the control valve to which control has been switched.

In order to shorten the distance between the measurement point measured by the flow sensor and the control point of the flow rate by the control valve during normal operation when there is no failure or the like in each control valve and improve responsiveness, the flow rate feedback control unit may be configured to control the second control valve in the initial state, and when the valve abnormality detection unit detects an abnormality in the second control valve, the control target switching unit may be configured to switch the control target of the flow rate feedback control unit to the first control valve.

A specific example of a configuration for detecting an abnormality in each control valve is one in which the valve abnormality detection unit is configured to detect an abnormality in the insulation state based on the voltage applied to the first control valve or the second control valve.

Another example of a configuration for detecting an abnormality in each control valve is one in which the valve abnormality detection unit is configured to detect an abnormality in the first control valve or the second control valve based on the absolute value of the deviation between the set flow rate and the flow rate measured by the flow sensor.

In this way, according to the fluid control device of the present invention, when the block is viewed in the width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point, so that the first control valve and the second control valve can be arranged side by side in the longitudinal direction of the block, and the width dimension of the block can be reduced while the fluids that have passed through each control valve can be merged in the post-merged flow path. As a result, the maximum flow rate can be increased compared to conventional methods while the fluid control device is configured compactly.

1 is a schematic diagram showing a hardware configuration of a fluid control device according to a first embodiment of the present invention; FIG. 2 is a schematic diagram showing a configuration of a fluid controller of the fluid control device according to the first embodiment. FIG. 1 is a schematic fluid circuit diagram of a fluid control device according to a first embodiment. FIG. 5 is a schematic diagram showing a hardware configuration of a fluid control device according to a second embodiment of the present invention. FIG. 5 is a schematic diagram showing the configuration of a fluid control device according to a third embodiment of the present invention. FIG. 13 is a schematic fluid circuit diagram of a fluid control device according to a fourth embodiment of the present invention. FIG. 13 is a schematic diagram showing a configuration of a fluid control device in a normal state according to a fifth embodiment of the present invention. FIG. 13 is a schematic diagram showing the configuration of a fluid control device when an abnormality occurs in the fifth embodiment of the present invention.

The first embodiment of the fluid control device 100 will be described with reference to Figures 1 to 3.

This fluid control device 100 is used, for example, in a semiconductor manufacturing process to supply various gases as fluids to a chamber at a desired set flow rate. In addition, a gas supply system is formed by arranging multiple fluid control devices 100 in parallel in the width direction.

As shown in Figures 1 and 2, the fluid control device 100 includes a block B having a longitudinal direction and an internal flow path L through which gas flows from one end to the other end, a first control valve V1 and a second control valve V2 attached to the block B, a pressure-type flow sensor FM that measures the flow rate of gas that passes through the first control valve V1 or the second control valve V2 and merges, and a fluid controller CB that controls the first control valve V1 and the second control valve V2 based on the measurement value of the flow sensor FM. Each part will be described in detail.

As shown in FIG. 1, block B is an elongated rectangular parallelepiped with a rectangular parallelepiped-shaped protrusion B1 formed in the center of one side of the block. The side with protrusion B1 is set as a mounting surface AS on which the first control valve V1, which is a fluid control device, and the first pressure sensor P1 and the second pressure sensor P2 constituting the flow sensor FM are mounted. The second control valve V2 is also provided on protrusion B1. That is, the first control valve V1, the second control valve V2, the first pressure sensor P1, and the second pressure sensor P2 are mounted on block B in order from the upstream side with respect to the internal flow path L. As shown in FIG. 1(b), block B has a certain width, and the first control valve V1, the second control valve V2, the first pressure sensor P1, and the second pressure sensor P2 also have approximately the same width as block B.

The first control valve V1 and the second control valve V2 are the same type, for example, piezo valves, in which a cylindrical valve structure consisting of a valve seat and a valve body is inserted into a hollow cylindrical recess formed in the mounting surface AS or the protruding portion B1, and a piezo actuator for driving the valve body is provided so as to protrude outward. Gas flows into the control valve from an inlet formed on the underside of the valve structure, and gas that passes through the gap between the valve body and the valve seat flows downstream from an outlet formed on the side of the valve structure. In the following description, the inlet and outlet of the first control valve V1 are referred to as the first inlet 11 and the first outlet 12, and the inlet and outlet of the second control valve V2 are referred to as the second inlet 21 and the second outlet 22.

The first pressure sensor P1 and the second pressure sensor P2 are of the same type and shape, and consist of a rectangular parallelepiped fixed part attached to the mounting surface AS, and a flat disk-shaped main body part on the upper side of the fixed part. Inside the main body part, a pressure-sensitive surface is provided so as to be perpendicular to the mounting surface AS. The first pressure sensor P1 presses and fixes the laminar flow element R, which is a fluid resistance housed in a recess formed in the mounting surface AS, by the lower surface of the fixed part. This laminar flow generator is a stack of multiple laminar flow element plates with microchannels formed therein, and a pressure difference is generated between the front and rear of the laminar flow element R by gas passing between the laminar flow element plates. A through hole is provided in the center of the laminar flow element R to guide the gas before passing between the laminar flow element plates into the first pressure sensor P1, and the first pressure sensor P1 measures the pressure upstream of the laminar flow element R. The second pressure sensor P2 measures the pressure of the gas after passing through the laminar flow element R.

In addition, on the bottom surface of block B, which is the surface opposite the mounting surface AS, there is an inlet port CIP through which gas is introduced into the internal flow path L, and an outlet port COP through which gas that has passed through the first control valve V1 or the second control valve V2 is discharged from the internal flow path L to the outside.

The portion of the internal flow path L formed on one end side of the block B is formed as two parallel flow paths. A first control valve V1 and a second control valve V2 are provided in each of the parallel flow paths. In addition, the portion of the internal flow path L formed on the other end side of the block B is formed as a single post-merged flow path CL where gas that has passed through the first control valve V1 or the second control valve V2 merges.

That is, by attaching each fluid control device to one block B, a fluid circuit as shown in Fig. 3 is formed. More specifically, as shown in Figs. 1 and 3, the internal flow path L further includes a pre-branch flow path BBL into which a fluid flows from an introduction port CIP, a first inflow flow path SL1 that branches from a branch point BP at the downstream end of the pre-branch flow path BBL and connects to the first inflow port 11 of the first control valve V1, a second inflow flow path SL2 that branches from a branch point BP at the downstream end of the pre-branch flow path BBL and has an end connected to the second inflow port 21 of the second control valve V2, a first outflow flow path EL1 that connects between the first outflow port 12 of the first control valve V1 and the junction point CP that is the upstream end of the junction flow path CL, and a second outflow flow path EL2 that connects between the second outflow port 22 of the second control valve V2 and the junction point CP that is the upstream end of the junction flow path CL. Here, the second inflow flow path SL2 and the first outflow flow path EL1 are each in a twisted position within block B.

When the block B is viewed in the width direction as shown in FIG. 1(a), the second inflow flow path SL2 and the first outflow flow path EL1 are arranged so as to overlap at one point. That is, when viewed in the width direction, the first outflow flow path EL1 and a part of the second inflow flow path SL2 are arranged so as to form a cross. More specifically, the first inflow flow path SL1 is formed in the center of the block B in the width direction, while the second inflow flow path SL2 advances obliquely from the center of the width direction toward the depth of the paper. In addition, since the second control valve V2 is provided on the protruding portion B1, the second inflow flow path SL2 advances in the depth direction of the paper in FIG. 1(a), and also advances from the bottom side of the block B to the mounting surface AS side. In other words, the flow direction of the second inflow flow path SL2 advances in the block B in the diagonal depth direction of the paper.

The first outlet flow passage EL1 advances from the front side of the page in FIG. 1(a) of block B toward the center in the width direction, and advances from the mounting surface AS side toward the bottom side, and together with the second outlet flow passage EL2, reaches the tip of the merging flow passage upstream of the laminar flow element R.

Next, the fluid controller CB will be explained with reference to Figure 2.

The fluid controller CB is a control circuit composed of a CPU, memory, an I/O channel, an A/D converter, a D/A converter, and other analog or digital circuits. The fluid controller CB performs the functions of at least the opening control unit 2, the flow rate calculation unit 3, and the flow rate feedback control unit 4 as shown in FIG. 2 by executing a program stored in the memory by the CPU and cooperating with various devices. The fluid controller CB of this embodiment controls the first control valve V1 and the second control valve V2 so that the same flow rate passes through the first control valve V1 and the second control valve V2, and the flow rate after merging is approximately the same as the set flow rate set by the user in the flow path CL. In other words, by flowing approximately the same amount of gas from the first control valve V1 and the second control valve V2, it is possible to achieve a maximum flow rate that is approximately twice as high as when there is only one control valve. Details of each part are explained below.

The opening control unit 2 controls the opening of the first control valve V1 based on the set flow rate and the gas supply pressure measured by a supply pressure sensor (not shown) provided in the flow path connected to the inlet port CIP of the fluid control device 100. In other words, the opening control unit 2 controls the opening so that the flow rate of gas passing through the first control valve V1 is 1/2 the set flow rate. Here, the post-confluence flow rate, which is the flow rate of gas flowing through the post-confluence flow path CL measured by the flow sensor FM, is not fed back to the opening control unit 2.

More specifically, the opening control unit 2 includes a target opening calculation unit 21 that calculates the target opening of the first control valve V1 based on the set flow rate and the supply pressure, and a voltage control unit 22 that applies a voltage corresponding to the target opening calculated by the target opening calculation unit 21 to the first control valve V1.

The target opening calculation unit 21 holds information about the conductance of the first control valve V1, and calculates the target opening from this conductance to achieve a flow rate of 1/2 the set flow rate at the current supply pressure.

The voltage control unit 22 holds information regarding the voltage-opening characteristics of the first control valve V1, and applies a voltage corresponding to the target opening to the first control valve V1.

In this way, when controlling the first control valve V1, information regarding the flow rate achieved by the first control valve V1 is not fed back, and open-loop control of the flow rate is performed based on the supply pressure and the set flow rate. Therefore, the flow rate of the gas output from the first control valve V1 is close to half the set flow rate, but the flow rate error remains uncorrected.

The flow rate calculation unit 3 calculates the post-junction flow rate, which is the flow rate of gas flowing through the post-junction flow path CL, based on the first pressure measured by the first pressure sensor P1 and the second pressure measured by the second pressure sensor P2. The flow rate calculation formula used by the flow rate calculation unit 3 is a known formula based on, for example, the differential pressure between the first pressure and the second pressure, or the difference between the square of the first pressure and the square of the second pressure.

The flow rate feedback control unit 4 performs flow rate feedback control of the opening of the second control valve V2 so as to reduce the deviation between the set flow rate and the post-merged flow rate calculated by the flow rate calculation unit 3. In other words, it is configured so that both the error in the flow rate realized by the first control valve V1 and the error in the flow rate realized by the second control valve V2 are reduced by controlling the second control valve V2.

In the fluid control device 100 configured in this manner, the first outlet flow passage EL1 through which gas flows out from the first control valve V1 formed in the block B and the second inlet flow passage SL2 through which gas flows into the second control valve V2 are arranged in a twisted position and are arranged to overlap at one point when viewed along the width direction, so that the first outlet flow passage EL1, the first control valve V1, and the second control valve V2 can be arranged side by side along the longitudinal direction to reduce the width dimension of the block B while allowing the fluid flowing out of the first control valve V1 and the second control valve V2 to flow into the confluence flow passage CL. Therefore, by using two control valves while keeping the width dimension of the fluid control device 100 compact, the maximum flow rate can be approximately doubled compared to the conventional method.

The opening of the first control valve V1 is controlled by the fluid controller CB based on the supply pressure, and the flow rate is controlled in an open loop. The second control valve V2 is controlled in a closed loop by feeding back the post-merged flow rate measured by the flow sensor FM. In this way, flow rate feedback control is performed only on the second control valve V2, so it is possible to prevent the control valves from interfering with each other.

Furthermore, because the opening of the first control valve V1 is controlled to allow a flow rate equivalent to 1/2 the set flow rate, the flow rates of gas passing through the first control valve V1 and the second control valve V2 can be made approximately the same value. Therefore, compared to when the gas flow rate is controlled by a single control valve, it is possible to accurately control the maximum flow rate to approximately twice as high.

Next, a fluid control device 100 according to a second embodiment of the present invention will be described with reference to FIG. 4. Note that the same reference numerals will be used to designate members corresponding to those described in the first embodiment.

In the second embodiment of the fluid control device 100, the valve bodies and valve seats of the first control valve V1 and the second control valve V2 are not inserted into the block B, and each is configured to be separate and independent.

Specifically, the first control valve V1 includes a first valve block VB1 in which a valve body and a valve seat are formed, and the lower surface of the first valve block VB1 is attached to the mounting surface AS of the block B, and is configured to communicate with the internal flow path L. That is, the first valve block VB1 has a connection surface CS formed on the lower surface thereof, through which a first inlet 11 through which gas, which is a fluid, flows into the interior and a first outlet 12 through which gas flows out from the interior. Therefore, by bringing the connection surface CS into contact with the mounting surface AS, as shown in FIG. 4(a), the downstream end opening of the first inlet 11 of the first inflow flow path SL1 that opens on the mounting surface AS is communicated with the first inlet 11, and the upstream end opening of the first outflow flow path EL1 that opens on the mounting surface AS is communicated with the first outlet 12. As shown in FIG. 4(b), the first outlet 12 is positioned offset in the width direction from the center of the first inlet 11 and is connected to the first outlet flow path EL2 that extends obliquely within the block B.

The second control valve V2 also has a structure similar to that of the first control valve V1. The second control valve V2 is equipped with a second valve block VB2 in which a valve body and a valve seat are formed inside, and the lower surface of the second valve block VB2 is attached to the mounting surface AS of the block B, and is configured to communicate with the internal flow path L. That is, the second valve block VB2 has a second inlet 21 through which gas, which is a fluid, flows into the inside and a second outlet 22 through which gas flows out from the inside, which are opened on the connection surface CS formed on the lower surface. Therefore, by contacting the connection surface CS with the mounting surface AS, as shown in FIG. 4(a), the downstream end opening of the second inlet 21 of the second inlet flow path SL2 opening on the mounting surface AS is communicated with the second inlet 21, and the upstream end opening of the second outlet flow path EL2 opening on the mounting surface AS is communicated with the first outlet 22. As shown in FIG. 4(b), the second outlet 22 is arranged shifted toward the center in the width direction with respect to the center of the first outlet 12. The second outlet flow path EL2 connected to this second outlet 22 extends in the height direction of the block B and is formed so as to intersect with the first outlet flow path 12.

The second inflow flow path SL2 extends obliquely from the center of the block B toward the rear in the width direction, and is arranged in a twisted position with the first outflow flow path EL2, which extends obliquely toward the front in the width direction. In addition, when the block B is seen through in the width direction as shown in FIG. 4(a), the first outflow flow path EL1 and the second inflow flow path SL2 are configured to overlap at one point.

With the fluid control device 100 of the second embodiment configured in this manner, there is no need to form a recess in the mounting surface AS of the block B to accommodate a portion of the first control valve V1 and the second control valve V2 inside, and each control valve V1, V2 can be arranged in its entirety outside the block B in a separated state. Therefore, a large space can be secured within the block B in which the first inflow passage SL1, the second inflow passage SL2, the first outflow passage EL1, and the second outflow passage EL2 can be formed. For this reason, even with a simple shape, it is easy to arrange the first outflow passage EL1 and the second inflow passage SL2 in a twisted position.

Next, a fluid control device 100 according to a third embodiment of the present invention will be described with reference to FIG. 5. Note that the same reference numerals will be used to designate members corresponding to those described in the first embodiment.

The fluid control device 100 of the third embodiment differs from that of the first embodiment in the configuration of the fluid controller CB. That is, while the fluid controller CB of the first embodiment controls the first control valve V1 and the second control valve V2 independently with different control laws, the fluid controller CB of the third embodiment changes the opening degree of the first control valve V1 and the second control valve V2 in synchronization.

Specifically, the fluid controller CB is equipped with a synchronization control unit 5 that controls the opening degree of the first control valve V1 and the opening degree of the second control valve V2 to be synchronized.

The synchronization control unit 5 applies the same voltage to each of the first control valve V1 and the second control valve V2 so that the deviation from the post-merged flow rate measured by the flow sensor FM is small. Here, since the first control valve V1 and the second control valve V2 are of the same type and model, applying the same voltage will result in approximately the same opening. The synchronization control unit 5 also changes the voltage applied to each control valve V1 depending on the deviation between the set flow rate and the measured flow rate, and is configured so that the value of the voltage applied at each time is approximately the same value. In other words, the first control valve V1 and the second control valve V2 are connected in parallel to the synchronization control unit 5, for example, and the voltage value applied to each is configured to always be the same value. The synchronization control unit 5 is also configured to correct the magnitude of the voltage applied depending on the supply pressure.

The fluid control device 100 of the third embodiment has a simple control law, yet can flow gas evenly through each of the control valves V1 and V2, achieving a large flow rate with high precision.

Next, a fluid control device 100 according to a fourth embodiment of the present invention will be described with reference to FIG. 6. Note that the same reference numerals will be used to designate members corresponding to those described in the first embodiment.

In the fourth embodiment of the fluid control device 100, a flow sensor FM is provided on the pre-branch flow path BBL upstream of each control valve V1, V2, and the flow sensor FM is a thermal flow sensor rather than a pressure type. This flow sensor FM includes a fluid resistance R provided on the pre-branch flow path BBL, a U-shaped thin tube TP that bypasses the fluid resistance R, a first coil C1 wound around the outside of the thin tube TP, and a second coil C2 provided downstream of the first coil C1 and wound around the outside of the thin tube TP. The fluid controller CB applies a voltage to each of the coils C1, C2 so that the temperature of each coil is kept constant, and the flow rate is calculated based on the difference in the voltage applied to each coil C1, C2.

Even with this fourth embodiment of the fluid control device 100, it is possible to enjoy substantially the same effects as the fluid control device 100 of the first embodiment.

Next, a fluid control device 100 according to a fifth embodiment of the present invention will be described with reference to Figures 7 and 8. Note that the same reference numerals will be used to designate members corresponding to those described in the first embodiment.

The fluid control device 100 of the fifth embodiment automatically continues flow control even if a failure occurs in either the first control valve V1 or the second control valve V2. In other words, this fluid control device 100 has a self-recovery and self-repair function for flow control.

Specifically, the first control valve V1 and the second control valve V2 in this fluid control device 100 are configured as normally open type valves. In other words, the first control valve V1 and the second control valve V2 are configured to be in a fully open state when no voltage is applied or when insulation breakdown occurs in the piezoelectric actuator. In addition, the first control valve V1 and the second control valve V2 are the same type of control valve and have approximately the same control characteristics.

Furthermore, as shown in FIG. 7, the fluid controller CB is configured to normally control the flow rate using only the second control valve V2, and to automatically switch to flow rate control using only the first control valve V1 when an abnormality occurs, as shown in FIG. 8. In other words, while the opening of the second control valve V2 is changed as appropriate during normal operation, the first control valve V2 is maintained, for example, in a fully open state.

Specifically, the fluid controller CB is configured to function as a flow rate calculation unit 3, a flow rate feedback control unit 4, a valve abnormality detection unit 6, and a flow rate control switching unit 7.

The flow rate calculation unit 3 has the same configuration as in the first embodiment, so a description thereof will be omitted. The flow rate feedback control unit 4 has the same basic control rules as in the first embodiment, but the control valve to be controlled is switched by the flow rate control switching unit 7. In this embodiment, the flow rate feedback control unit 4 normally controls the second control valve V2, and when an abnormality occurs, controls the first control valve V1.

The valve abnormality detection unit 6 normally monitors at least the second control valve V2, which is the subject of control by the flow rate feedback control unit 4. That is, the valve abnormality detection unit 6 monitors the value of the voltage applied to the second control valve V2, and also monitors the absolute value of the deviation between the set flow rate calculated by the flow rate feedback control unit 4 and the post-merged flow rate. For example, if the voltage applied to the second control valve V2 falls below a predetermined value, the valve abnormality detection unit 6 determines that insulation breakdown has occurred in the piezo actuator. In addition, if the absolute value of the deviation described above exceeds a predetermined value and this state is maintained for a predetermined period of time, the valve abnormality detection unit 6 determines that flow rate control cannot be performed due to an abnormality in the second control valve V2.

When the valve abnormality detection unit 6 detects an abnormality in the second valve V2, the flow control switching unit 7 switches the flow control from the second control valve V2 to the first control valve V1 as shown in FIG. 8. That is, the flow feedback control unit 4 applies voltage only to the first control valve V1, and flow control continues. In addition, since the second control valve V2 to which voltage is no longer applied is a normally open type, it remains fully open.

In this way, with the fluid control device 100 of the fifth embodiment, if an abnormality is detected in the second control valve V2 while flow control is being performed solely by the second control valve V2, flow control can be automatically switched to flow control by the first control valve V2. Therefore, even if the flow control cannot be continued due to an abnormality in the second control valve V2 and the set flow rate cannot be maintained, flow control by the first control valve V1 is started, and the flow rate can be automatically restored to the set flow rate.

In addition, since the second control valve V2 is maintained in a fully open state after flow control by the first control valve V1 has begun, the flow resistance by the second control valve V2 itself can be minimized. Therefore, flow control by the first control valve V1 can be performed under conditions almost equivalent to those of the second control valve V2, making it possible to maintain constant flow control accuracy, etc.

Other embodiments will be described.

The block may not have a protruding portion that protrudes from the mounting surface. In other words, the first control valve and the second control valve may be mounted on mounting surfaces at the same height. Even in this case, the first outlet flow passage and the second inlet flow passage are in a twisted position, and are arranged so that they intersect at one point when viewed along the width direction.

The position at which the protrusion is provided is not limited to that shown in the above embodiment. For example, a protrusion may be provided at the position where the first control valve is provided, so that the first control valve is positioned higher in the block than the second control valve.

The flow sensor is not limited to a pressure type flow sensor, but may be based on other measurement principles such as a thermal type or ultrasonic type. Also, the fluid flowing through the internal flow path may be a liquid, not just a gas.

The control valve controlled by the aperture control unit is not limited to the first control valve, but may be the second control valve. In such a case, the flow rate feedback control unit may be configured to control the first control valve. In addition, the pressure used in the aperture control unit is not limited to the supply pressure. For example, the aperture control unit may control the aperture of the first control valve or the second control valve based on a first pressure measured by a first pressure sensor constituting a pressure-type flow sensor.

The opening control unit is not limited to one that operates to achieve a flow rate that is 1/2 the set flow rate. For example, it may be one that controls the first control valve or the second control valve to achieve a flow rate that is a predetermined multiple smaller than the set flow rate.

The fluid control device is not limited to one that controls the flow rate, but may also control the pressure. With the fluid control device according to the present invention, the maximum flow rate can be made larger than before, even when controlling the pressure.

The second inflow passage is not limited to branching off from the first inflow passage, and may be formed to connect between the introduction port and the second inlet. In addition, two introduction ports may be provided, and the first inflow passage and the second inflow passage may each receive fluid from a separate fluid supply source.

In the fifth embodiment, the flow rate is controlled only by the second control valve under normal circumstances, and only by the first control valve after an abnormality is detected. However, the flow rate may be controlled only by the first control valve under normal circumstances, and only by the second control valve after an abnormality is detected. In addition, for control valves that do not normally perform flow rate control, an operating maintenance voltage may be applied so that they can operate immediately after switching. In addition, for control valves that do not normally perform flow rate control, for example, they may be configured to perform pressure control, and to perform flow rate control after an abnormality is detected.

In addition, the fluid control device of the fifth embodiment is not limited to one in which both the first control valve and the second control valve are configured as a normally open type, and the first control valve and the second control valve may be configured as a normally closed type in which they are kept fully closed when no voltage is applied. Also, one of the first control valve or the second control valve may be configured as a normally open type and the other as a normally closed type. Even in such a configuration, if an abnormality occurs in the control valve that was performing flow control, flow control can be automatically continued with another control valve. Therefore, a self-recovery and self-repair function for flow control can be realized in the same way as described in the fifth embodiment.

In addition, various modifications of the embodiments and combinations of parts of each embodiment may be made without going against the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100... Fluid control device V1... First control valve V2... Second control valve SL1... First inflow passage SL2... Second inflow passage EL1... First outflow passage EL2... Second outflow passage FM... Flow rate sensor CB... Fluid controller 2... Opening control section 21... Target opening calculation section 22... Voltage control section 3... Flow rate calculation section 4... Flow rate feedback control section 5... Synchronization control section 6... Valve abnormality detection section 7... Flow rate control switching section

Claims (16)

A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first inlet passage connected to a first inlet through which a fluid flows into the first control valve;
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
a second outlet passage connected to a second outlet port through which fluid flows out of the second control valve;
a pre-branch flow path provided upstream of the first inflow flow path and the second inflow flow path branches into the first inflow flow path and the second inflow flow path from a branch point, and the first outflow flow path and the second outflow flow path merge into a post-junction flow path provided downstream of the first outflow flow path and the second outflow flow path,
The fluid control device, when viewed through the block in a width direction, has the first outlet flow passage and the second inlet flow passage arranged to overlap at one point. A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
When the block is seen through in a width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point,
The block is
a mounting surface on which the fluid control device is mounted;
a protruding portion protruding from the mounting surface by a predetermined amount,
At least one of the first control valve and the second control valve is attached to the mounting surface. The fluid control device according to claim 2, wherein the second control valve is provided on the protrusion. A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
When the block is seen through in a width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point,
the first control valve includes a first valve block having a first contact surface that contacts a surface of the block, and a first inlet through which fluid flows into the first valve block and a first outlet through which fluid flows out of the first valve block are open on the first contact surface;
the second control valve comprises a second valve block having a second contact surface that contacts a surface of the block, and the second inlet through which fluid flows into the second valve block and the second outlet through which fluid flows out of the second valve block open on the second contact surface. A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
When the block is seen through in a width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point,
The fluid control device, wherein the first control valve and the second control valve have the same width dimension as the block. A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
When the block is seen through in a width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point,
The internal flow path is
a post-junction flow path in which the fluids that have passed through the first control valve or the second control valve join and flow;
a second outlet flow passage connecting a second outlet port through which fluid flows out of the second control valve and the post-junction flow passage, and a downstream side of the first outlet flow passage is connected to the post-junction flow passage,
a flow rate sensor for measuring a flow rate of the fluid flowing through the post-junction flow path;
The fluid control device further comprises a fluid controller that controls at least one of the first control valve or the second control valve based at least on the flow rate measured by the flow sensor. A block extending in a longitudinal direction with a predetermined width;
an internal flow passage formed within the block and extending along the longitudinal direction;
a first control valve attached to the block;
a second control valve connected in parallel with the first control valve;
The internal flow path is
a first outlet passage connected to a first outlet port through which fluid flows out of the first control valve;
a second inlet passage connected to a second inlet through which fluid flows into the second control valve;
When the block is seen through in a width direction, the first outlet flow path and the second inlet flow path are arranged to overlap at one point,
The internal flow path is
a first inlet passage connected to a first inlet through which a fluid flows into the first control valve;
A pre-branch flow path, the downstream side of which is connected to the first inlet flow path and the second inlet flow path,
a flow rate sensor for measuring a flow rate of a fluid flowing through the pre-branch flow path;
The fluid control device further comprises a fluid controller that controls at least one of the first control valve or the second control valve based at least on the flow rate measured by the flow sensor. The fluid controller,
an opening control unit that controls the opening of either the first control valve or the second control valve so that a shared target flow rate that is a predetermined multiple of a set flow rate flows;
8. The fluid control device according to claim 6 or 7, further comprising a flow rate feedback control section that controls the other of the first control valve or the second control valve so as to reduce a deviation between the set flow rate and the flow rate measured by the flow sensor. The opening control unit,
a target opening calculation unit that calculates a target opening corresponding to the allocated target flow rate based on a pressure on the upstream side of the first control valve;
9. The fluid control device according to claim 8, further comprising a voltage control unit that applies a voltage corresponding to the target opening to the other of the first control valve and the second control valve. A fluid control device according to claim 8 or 9, in which the shared target flow rate is set to 1/2 the set flow rate. The fluid controller,
8. The fluid control device according to claim 6, further comprising a synchronization control section that controls the opening degree of the first control valve and the opening degree of the second control valve so as to be synchronized with each other. the first control valve and the second control valve are of the same type,
The fluid control device according to claim 11, wherein the synchronization control unit applies the same voltage to each of the first control valve and the second control valve so as to reduce a deviation from the flow rate measured by the flow rate sensor. The fluid controller,
a flow rate feedback control unit that controls either the first control valve or the second control valve so as to reduce a deviation between a set flow rate and a flow rate measured by the flow rate sensor;
a valve abnormality detection unit that detects an abnormality in the first control valve or the second control valve;
7. The fluid control device according to claim 6, further comprising: a control target switching unit that switches the control valve to be controlled by the flow rate feedback control unit when the valve abnormality detection unit detects an abnormality in the first control valve or the second control valve controlled by the flow rate feedback control unit. the flow rate feedback control unit controls the second control valve in an initial state,
14. The fluid control device according to claim 13, wherein when the valve abnormality detection unit detects an abnormality in the second control valve, the control target switching unit switches the control target of the flow rate feedback control unit to the first control valve. The fluid control device according to claim 13 or 14, wherein the valve abnormality detection unit is configured to detect an abnormality in the insulation state based on the voltage applied to the first control valve or the second control valve. The fluid control device according to any one of claims 13 to 15, wherein the valve abnormality detection unit is configured to detect an abnormality in the first control valve or the second control valve based on the absolute value of the deviation between the set flow rate and the flow rate measured by the flow sensor.