JP7790711B2 - Valve system with anti-locking function - Google Patents

Description

The valve system with anti-locking function described in this application relates to technology for eliminating the locking phenomenon in which the basic valve cannot open due to fluid stagnation in the basic flow path.

Industrial plants often have piping systems that transport steam generated in boilers at high temperature and pressure to the destination equipment. When the steam is used in the destination equipment, drain (condensed water from the steam) is generated and discharged from the destination equipment's exhaust pipe. At this time, steam may also flow out of the exhaust pipe along with the drain, but to avoid steam loss, it is necessary to discharge only the drain to the outside.

For this reason, a steam trap is installed in the discharge pipe. A float-type steam trap has a hollow float built into the valve chamber. As condensate flows into the valve chamber of the steam trap and accumulates, the float rises and opens the condensate discharge port located at the bottom of the valve chamber, automatically discharging the condensate to the outside. After the condensate has been discharged, the float descends and closes the condensate discharge port, preventing steam leakage.

However, in steam traps, depending on the conditions of the inflowing steam and condensate, steam can get trapped in part of the condensate in the piping system, including the steam trap valve chest, blocking the flow of condensate and preventing it from being properly discharged. This phenomenon is known as steam locking.

One technology for eliminating this steam locking phenomenon is the heating cylinder disclosed in Patent Document 1, listed below. This heating cylinder 100 supplies steam to the cylinder body 10, heating an object that comes into contact with the outer surface of the cylinder body 10.

In the cylinder body 10, steam that has absorbed heat condenses to produce drain. This drain is extracted from the drain pipe 20 through the drain piping 31 and is discharged by the operation of a steam trap 40 installed on the drain piping 31. A bypass pipe 32 is installed on the drain piping 31, connecting the upstream and downstream sides of the steam trap 40, and a valve 50 is installed on this bypass pipe 32. The valve 50 opens and closes under the control of the control unit 60.

When steam locking occurs, the drain is not properly drained and accumulates inside the cylinder body 10, causing the water level to rise. This rise in water level is detected by the water level sensor 13, and based on this, the control unit 60 opens the valve 50. As a result, the drain is diverted and drained through the bypass pipe 32, eliminating the steam locking phenomenon.

Japanese Patent Application Laid-Open No. 2017-86248

In the heating cylinder 100 disclosed in Patent Document 1, if steam locking occurs, the valve 50 opens and drains the drain from the bypass pipe 32 regardless of the drain retention status. However, with the steam locking phenomenon, it is not always clear where in the piping system the steam is present, and the drain retention status can vary.

For this reason, if valve 50 is fully opened to drain condensate regardless of the condensate accumulation status, steam may leak from bypass pipe 32 in the short period of time between the end of the steam locking phenomenon and the closing of valve 50. Depending on the state of steam and condensate transport, steam locking may occur frequently, and condensate will be drained from bypass pipe 32 each time, resulting in steam leakage losses even if the steam leaks for only a short time.

The objective of the present application is to provide a valve system with an anti-locking function that can reliably prevent steam leakage due to the elimination of the locking phenomenon.

The valve system with the locking release function is
A basic flow path through which a fluid passes from upstream to downstream.
a basic valve that is provided on the basic flow path and can be opened or closed, blocking the passage of the fluid when closed and allowing the passage of the fluid when opened;
an opening/closing means for closing or opening the basic valve;
a bypass flow path connecting the upstream basic flow path of the basic valve with the downstream basic flow path;
an auxiliary valve that is provided on the bypass flow path and can be opened or closed, and that opens when a locking phenomenon occurs in which the basic valve cannot be opened due to a stagnation state of the fluid in the basic flow path, and allows the fluid to pass through the bypass flow path;
It is equipped with
The auxiliary valve is capable of adjusting the flow rate of the fluid passing through the bypass flow path.
It is characterized by:

In the valve system with anti-locking function related to this application, the auxiliary valve provided in the bypass flow path opens in response to the occurrence of a locking phenomenon in which the main valve cannot open due to fluid stagnation in the main flow path, allowing fluid to pass through the bypass flow path. This auxiliary valve is also capable of adjusting the flow rate of fluid passing through the bypass flow path.

As a result, fluid can be appropriately discharged through the bypass flow path depending on the fluid stagnation status in the main flow path, and the auxiliary valve can be closed immediately after the locking phenomenon is resolved. This ensures that steam leakage caused by the elimination of the locking phenomenon is prevented.

1 is an overall configuration diagram showing a first embodiment of a valve system having a locking release function according to the present application. 2 is a cross-sectional view of the steam trap 1 taken along the arrows II-II in FIG. 1. FIG. 3 is a cross-sectional view of the bypass valve 4 in the direction of the arrows III-III shown in FIG. 1. 4 is an enlarged cross-sectional view of the bypass valve seat 48 and the bypass valve body 62 shown in FIG. 3 in an open state. FIG. 4 is an enlarged cross-sectional view of the bypass valve seat 48 and the bypass valve body 62 shown in FIG. 3 in the vicinity thereof, showing the closed state of the valve. FIG. FIG. 2 is a cross-sectional view of a steam trap 200 used in a second embodiment of a valve system having an anti-locking function according to the present application. FIG. 2 is a cross-sectional view of a bypass valve 220 used in a second embodiment of a valve system having an anti-locking function according to the present application. 7 is a graph showing the relationship between the change in temperature detected by the temperature sensor 201 shown in FIG. 6 and the opening degree of the valve. 10 is a graph showing changes in the temperature detected by the temperature sensor 201 in the third embodiment of the valve system having an anti-locking function according to the present application. 10 is a graph showing the relationship between the inclination angle of the center line in the graph shown in FIG. 9 and the opening degree of the valve.

[Terminology used in the embodiment]
The main terms used in the embodiments correspond to the following elements of the valve system having an anti-locking function according to the present application:

Steam trap 1, 200: basic valve Bypass valve 4, 220: auxiliary valve Float 10: opening/closing means Bypass valve port 49: auxiliary valve port portion Bypass valve body 62: valve body portion Inlet pipe 71 and outlet pipe 72: basic flow path Bypass pipes 73, 74: detouring flow path Axis L1: reference line Temperature sensor 201: detection means, temperature detection means Temperature signal: detection signal Steam or condensate: fluid Note that the steam locking phenomenon refers to a phenomenon in which steam gets trapped in part of a piping system, including pipes and valves, obstructing the inflow of condensate and causing the valve to malfunction. Furthermore, a stagnation of fluid in the basic flow path refers to a situation in which condensate gets trapped in the valve chest of a steam trap or upstream of the valve chest, for example.

[First embodiment]
A first embodiment of a valve system with an anti-locking function according to the present invention will be described with reference to Figures 1 to 5. The valve system in this embodiment is installed in a piping system of an industrial plant, etc. As shown in Figure 1, this valve system includes a steam trap 1, which is connected to an inlet pipe 71 and an outlet pipe 72.

The inlet pipe 71 is connected to the main pipe (not shown) of the piping system through which steam and condensate generated from the steam flow, and condensate flows into the steam trap 1 through the inlet pipe 71. The steam trap 1 appropriately discharges the condensate that has flowed in and accumulated inside to the outlet pipe 72. Following the flow of steam and condensate, the inlet pipe 71 side is upstream and the outlet pipe 72 side is downstream.

Bypass pipes 73 and 74 are connected to the inlet pipe 71 and outlet pipe 72, respectively, with the steam trap 1 in between. These bypass pipes 73 and 74 are equipped with bypass valves 4. The bypass valve 4 is normally closed, blocking the passage of condensate through the bypass pipes 73 and 74. However, when steam locking occurs, the valve opens, allowing the condensate to bypass the inlet pipe 71 and be discharged into the outlet pipe 72.

(Explanation of Steam Trap 1)
The configuration and operation of the steam trap 1 will be explained with reference to Figure 2. The steam trap 1 has a main body composed of a casing 7 and a casing lid 20. The casing 7 and the casing lid 20 are fixed together with bolts to form an airtight valve chest 16 inside.

Steam and condensate flow into this valve chest 16 in the direction of arrow 91 from the inlet pipe 71 through the inlet 7a. A strainer 12 with a mesh section is provided upstream of the valve chest 16, and the steam and condensate pass through this strainer 12 and flow into the valve chest 16. As a result, foreign matter such as dirt and scale mixed in with the steam and condensate are captured by the mesh section of the strainer 12.

A valve seat 27 is fixedly attached to the casing lid 20 downstream of the valve chamber 16, and a valve port 28 is formed in this valve seat 27. The valve port 28 communicates with the internal space of the valve seat 16 and further forms a flow path that communicates with the lid-side flow path 24 formed in the casing lid 20, the outflow path 14 formed in the casing 7, and the outflow port 7b. This allows drainage accumulated in the valve chamber 16 to be discharged from the valve port 28 toward the outflow pipe 72 in the direction of arrow 92.

A float 10 is placed in the valve chamber 16. The float 10 is configured as a hollow sphere and is positioned so that it can float within the valve chamber 16. Under normal conditions, the float 10 sits on the valve seat 27, closing the valve port 28 and preventing steam leakage from the steam trap 1. Multiple support pieces 18 are provided within the valve chamber 16, allowing the float 10 to stably seat on the valve seat 27.

When condensate accumulates in the valve chamber 16 and the condensate level rises, the float 10 rises and opens accordingly. When the float 10 rises and opens, the condensate accumulated in the valve chamber 16 is driven by the force of the high pressure in the piping and escapes from the valve port 28 in the direction of arrow 92, and is discharged into the outflow pipe 72. After being discharged, the condensate level in the valve chamber 16 drops, and the float 10 also drops and seats on the valve seat 27, returning to a closed state. In this way, the steam trap 1 repeatedly closes and opens depending on the condensate level in the valve chamber 16, and discharges condensate from the piping system as appropriate.

The casing cover 20 has a curved bimetal 22 mounted on the downstream side of the valve chamber 16. This bimetal 22 is a temperature-sensitive material made by bonding two thin alloy plates with different expansion coefficients together. When the ambient temperature is high, the bimetal 22 bends and retracts its tip, but when the ambient temperature drops, it changes shape and opens wide in response. This causes the tip of the bimetal 22 to push up the float 10, forcibly opening the valve orifice 28 regardless of the drain water level. Figure 2 shows the state in which the bimetal 22 pushes up the float 10 and opens the valve orifice 28.

This bimetal 22 is provided to properly discharge low-temperature air and condensate from the valve orifice 28. For example, in the initial stages after the equipment starts operating, the valve chamber 16 is filled with low-temperature air, so the bimetal 22 pushes up the float 10, forcing the valve orifice 28 open. As a result, when steam transfer begins, the initial air is properly discharged from the valve orifice 28, preventing air binding. Similarly, low-temperature condensate flowing into the valve chamber 16 is properly discharged from the valve orifice 28.

When high-temperature steam subsequently flows into the valve chamber 16, the bimetal 22 reacts to the high temperature, causing the curved portion to deform, and the tip of the bimetal 22 is retracted toward the valve orifice 28. As a result, the float 10 continues to rise and fall in accordance with the accumulated drain water level as described above, without interference from the bimetal 22.

However, in the steam trap 1, a clogged drain condition can occur in which foreign matter blocks the valve port 28, preventing the drain from being properly discharged. As mentioned above, foreign matter is captured by the strainer 12, but small foreign matter passes through the strainer 12 and enters the valve chamber 16. To deal with this type of clogged condition, the steam trap 1 in this embodiment is provided with a cleaning bar 30. Note that in Figure 2, the cleaning bar 30 is shown as a side view rather than a cross section.

The cleaning bar 30 is threadedly engaged with a cylindrical holder 33 fixed to the casing lid 20, and can be rotated to move back and forth in the axial direction. The bar tip 31 of the cleaning bar 30 is located in the internal space of the valve seat 27 and is positioned toward the valve orifice 28.

An operating groove 32 is formed at the rear end of the cleaning bar 30. When cleaning the valve orifice 28, the operator inserts a tool or the like into the operating groove 32 and rotates it to advance the cleaning bar 30 toward the valve orifice 28. This allows the bar tip 31 of the cleaning bar 30 to enter the valve orifice 28 and remove foreign matter from the valve orifice 28.

(Explanation of bypass valve 4)
Next, the configuration of the bypass valve 4 will be described with reference to Figures 3 to 5. As shown in Figure 3, the bypass valve 4 includes a bypass casing 40. A bypass inlet 40a and a bypass outlet 40b are formed coaxially in the bypass casing 40. A bypass pipe 73 is connected to the bypass inlet 40a, and a bypass pipe 74 is connected to the bypass outlet 40b (see Figure 1).

A blow passage 41 is formed within the bypass casing 40, and this blow passage 41 is connected to the bypass inlet 40a. A cylindrical screen 45 with a mesh section is placed in the blow passage 41.

When condensate flows through the bypass pipe 73, it flows in from the bypass pipe 73 through the bypass inlet 40a in the direction of arrow 93. The inflowing condensate passes through the mesh portion of the screen 45, which captures foreign matter such as dirt and scale mixed in the condensate. Furthermore, a connecting passage 42 communicating with the blow passage 41 is formed within the bypass casing 40, and a bypass valve port passage 44 communicating with the bypass outlet 40b is also formed.

An opening is formed in the side of the bypass casing 40, and a cylindrical retaining member 50 is attached to cover this opening. The retaining member 50 is attached and fixed to the opening of the bypass casing 40 by a screw connection. A bypass valve chamber 43 is formed between the bypass casing 40 and the retaining member 50, and is kept airtight by a gasket 59.

The bypass valve chamber 43 is connected to the aforementioned connecting passage 42 and bypass valve port passage 44. A disk-shaped bypass valve seat 48 is attached to the bypass valve port passage 44 at the connection with the bypass valve chamber 43. This bypass valve seat 48 has a cylindrical bypass valve port 49 that opens toward the bypass valve chamber 43. The center line of the bypass valve port 49 is aligned with the axis L1.

In other words, the bypass valve 4 has a flow path formed by the bypass inlet 40a, blow passage 41, connecting passage 42, bypass valve chamber 43, bypass valve port 49, bypass valve port passage 44, and bypass outlet 40b, and drainage that flows into the bypass inlet 40a can be discharged from the bypass outlet 40b in the direction of arrow 93 to arrows 94 and 95.

A through-hole is formed in the center of the cylindrical retaining member 50, with the centerline of this through-hole aligned with the axis L1. A bypass valve stem 61 is attached to and passes through the through-hole of the retaining member 50. Note that in Figures 3 to 5, the bypass valve stem 61 is shown as a side view rather than a cross section. The bypass valve stem 61 is equipped with a conical bypass valve disc 62 at its tip, with the apex of the bypass valve disc 62 positioned on the axis L1. A valve stem operating groove 67 is formed at the rear end of the bypass valve stem 61.

A screw thread 63 is formed near the tip of the bypass valve stem 61, and is attached by threading into a thread groove 69 formed in a through-hole in the retaining member 50. In other words, by inserting a tool or the like into the valve stem operating groove 67 and rotating it, the bypass valve stem 61 moves back and forth along the axis L1 as the threads are threaded into it.

To maintain the airtightness of the bypass valve chamber 43, the retaining member 50 is provided with a packing 64 with a central hole, through which the bypass valve stem 61 passes. The packing 64 is pressurized by a pressing member 65 that threads onto the retaining member 50, reliably maintaining the airtightness of the bypass valve chamber 43. A cap 51 is removably attached to the rear end of the retaining member 50, and is positioned to cover the valve stem operating groove 67 of the bypass valve stem 61.

Figures 4 and 5 are enlarged cross-sectional views of the bypass valve seat 48 and the bypass valve body 62. As shown in Figure 4, the bypass valve seat 48 has a protrusion 49a that protrudes toward the bypass valve chamber 43, and a bypass valve port 49 is formed at the tip of this protrusion 49a. This bypass valve port 49 has a cylindrical shape with a thickness of 82.

A wide-opening portion 49b that is continuous with the bypass valve port 49 is formed inside the bypass valve seat 48. The wide-opening portion 49b is configured as an inclined surface that widens from the tip end, where the bypass valve port 49 is formed, toward the rear end. A step portion 49c that is continuous with the wide-opening portion 49b is formed inside the bypass valve seat 48, and a cylindrical portion 49d that is continuous with the step portion 49c is also formed.

Meanwhile, a valve element base 61a is integrally formed at the tip of the bypass valve stem 61, and the aforementioned bypass valve element 62 is attached to this valve element base 61a. The protruding length 81 of the bypass valve element 62 from the valve element base 61a is formed to be sufficiently longer than the thickness 82 of the bypass valve port 49. In this embodiment, the protruding length 81 is configured to be approximately six times the thickness 82. The diameter of the conical bottom portion of the bypass valve element 62 is larger than the opening diameter of the bypass valve port 49.

Figure 4 shows the open state of the bypass valve 4 when the bypass valve stem 61 reaches its limit in the direction of arrow 99 (retraction direction). In this open state, the thread 63 of the bypass valve stem 61 and the thread groove 69 of the retaining portion 50 reach their limit in the direction of arrow 99, and the bypass valve body 62 is completely retracted in the direction of arrow 99 from the bypass valve port 49.

In contrast, Figure 5 shows the bypass valve 4 in a closed state, with the inclined side of the conical bypass valve body 62 abutting against the tip edge of the bypass valve port 49, causing the bypass valve stem 61 to be positioned at the limit in the direction of arrow 98 (entry direction). This completely closes the bypass valve port 49, blocking the passage of condensate.

(Explanation of the operation to eliminate the steam locking phenomenon)
As mentioned above, under normal circumstances, condensate generated from steam in a piping system is appropriately discharged from the outflow pipe 72 by repeatedly opening and closing the steam trap 1 (see Figure 1). However, if steam locking occurs, in which steam is trapped in part of the condensate in the piping system, condensate will no longer flow into the valve chest 16 of the steam trap 1, preventing the float 10 from floating. As a result, the steam trap 1 will be unable to open, and condensate will not be properly discharged.

When this type of steam locking phenomenon occurs, in this embodiment, the bypass valve 4 is opened while adjusting its opening, and the condensate is diverted through bypass pipes 73 and 74 and discharged into outlet pipe 72. This allows steam present in the piping system to be discharged along with the condensate, eliminating the steam locking phenomenon. The operation for eliminating this steam locking is explained in detail below.

Under normal circumstances, the bypass valve 4 is in the closed state shown in Figure 5. In this closed state, the operator recognizes that the discharge of condensate from the outflow pipe 72 has stopped and understands that steam locking has occurred. Then, remove the cap 51 of the bypass valve 4 shown in Figure 3, insert a tool or similar into the valve stem operating groove 67 of the bypass valve stem 61, and rotate it in the loosening direction.

As a result, the bypass valve stem 61 moves in the direction of arrow 99 along the axis L1, and the bypass valve element 62 also gradually retracts away from the tip edge of the bypass valve port 49. In this embodiment, the state in which the bypass valve element 62 is away from the tip edge of the bypass valve port 49 is the open state.

Here, as mentioned above, the bypass valve element 62 has a conical shape, with its side surfaces formed as slopes. Therefore, depending on the inclination of the slope of the bypass valve element 62, the opening of the bypass valve port 49 gradually increases as the bypass valve element 62 retracts in the direction of arrow 99. Conversely, when the bypass valve stem 61 is rotated in the tightening direction from the open state, the opening of the bypass valve port 49 gradually decreases depending on the inclination of the slope of the bypass valve element 62.

In other words, as the operator rotates the bypass valve stem 61 in the loosening or tightening direction, the opening of the bypass valve 4 changes, allowing the flow rate of drain water diverted and discharged through the bypass pipes 73 and 74 to be freely adjusted.

However, with the steam locking phenomenon, it is not always clear how much steam is present in which part of the piping system. For this reason, it is difficult to determine the timing for closing bypass valve 4. Furthermore, if bypass valve 4 is suddenly opened fully, it may take time for bypass valve 4 to be fully closed after the steam locking phenomenon is resolved, which could result in useful steam leaking from bypass pipes 73 and 74, even though it should be transported through the piping system.

In this regard, in this embodiment, the operator can adjust the flow rate of the bypass pipes 73 and 74 while rotating the bypass valve stem 61 to discharge the drain, allowing the bypass valve 4 to be gradually opened slightly to resolve the steam locking phenomenon. Therefore, once the steam locking phenomenon is resolved, the bypass valve 4 can be immediately closed (Figure 5).

In other words, condensate can be appropriately discharged through bypass pipes 73 and 74 depending on the condensate accumulation status, and bypass valve 4 can be closed immediately after the steam locking phenomenon is resolved, thereby reliably preventing steam leakage when the steam locking phenomenon is resolved.

As mentioned above, the protruding length 81 of the bypass valve body 62 is formed to be sufficiently longer than the thickness 82 of the bypass valve port 49 (see Figure 4), so the bypass valve port 49 can be reliably opened even when the pressure in the piping system is low.

That is, particularly under low pressure, a liquid film is generated by the surface tension of the drain, and this liquid film can block the bypass valve orifice 49. Furthermore, if the thickness of the bypass valve orifice 49 is longer than the protruding length of the bypass valve disc 62, even if the bypass valve disc 62 enters the bypass valve orifice 49, the liquid film may remain blocking the bypass valve orifice 49, preventing the valve from opening.

In this regard, in this embodiment, the protrusion length 81 of the bypass valve element 62 is sufficiently longer than the thickness 82 of the bypass valve port 49, and when the bypass valve element 62 is inserted into the bypass valve port 49, the tip of the bypass valve element 62 can be positioned protruding toward the rear end of the bypass valve port 49. As a result, the tip of the bypass valve element 62 breaks through the liquid film, allowing the condensate to flow along the slope of the bypass valve element 62 and ensuring the valve opening. Therefore, the effects of the surface tension of the condensate can be avoided even under low pressure, and the condensate can be reliably discharged from the bypass pipes 73 and 74.

[Second embodiment]
Next, a second embodiment of a valve system with an anti-locking function according to the present invention will be described with reference to Figures 6 to 8. Components with the same configurations and operations as those of the first embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted. This embodiment is substantially different from the first embodiment in that a temperature sensor 201 is provided in the steam trap 200 (see Figure 6), and an actuator 205 is provided in the bypass valve 220 (see Figure 7).

As shown in Figure 6, a temperature sensor 201 is attached to the casing 7 of the steam trap 200. In Figure 6, the temperature sensor 201 is shown in a side view. The temperature sensor 201 has a detection head 202, which is provided upstream of the valve port 28. In this embodiment, the detection head 202 is disposed to the side of the valve chest 16, and by detecting the temperature of the casing 7, the detection head 202 detects the temperature of the condensate remaining in the valve chest 16. The temperature sensor 201 has communication capabilities, and can transmit the temperature of the condensate in the valve chest 16 detected by the detection head 202 as a temperature signal.

The temperature signal emitted by the temperature sensor 201 is supplied to the bypass valve 220. As shown in Figure 7, the bypass valve 220 in this embodiment is equipped with an actuator 205. In Figure 7, the actuator 205 is shown as a block diagram. The actuator 205 has a drive unit 209 mainly composed of a motor, and this drive unit 209 is connected to the rear end of the bypass valve stem 61. The actuator 205 further has a receiver 206, a control unit 207, and a memory 208.

The temperature signal emitted by the temperature sensor 201 (Figure 6) is received by the receiver 206 directly or indirectly (for example, via a server), and this temperature signal is input from the receiver 206 to the controller 207. The controller 207 then issues a command to the driver 209 in accordance with data (described below) stored in the memory 208, causing the bypass valve stem 61 to rotate and move back and forth along the axis L1 in the directions of arrows 98 and 99.

Figure 8 is a graph showing the relationship between the change in the detected temperature detected by the temperature sensor 201 and the valve opening. The change in the detected temperature is shown as curve x. Data showing the relationship between the detected temperature and the valve opening is stored in advance in memory 208.

Under normal circumstances, condensate generated in the piping system flows from the inlet pipe 71 into the valve chest 16 of the steam trap 200, and as the float 10 floats, the valve port 28 opens appropriately, allowing the condensate to be discharged into the outlet pipe 72. In other words, under normal circumstances when steam locking is not occurring, high-temperature condensate continuously flows into the valve chest 16 of the steam trap 200, and the temperature detected by the temperature sensor 201 remains at a nearly constant high temperature. The reference temperature a20 shown in Figure 8 is a threshold value for determining this constant high temperature under normal circumstances, and is stored in advance in the memory 208.

If steam locking occurs, where steam is trapped in part of the drain in the piping system, the flow of drain into the valve chamber 16 is obstructed, preventing the float from rising and preventing the drain trapped in the valve chamber 16 from being discharged. As a result, the drain in the valve chamber 16 loses heat over time, gradually decreasing in temperature, and the detected temperature falls below the reference temperature a20.

When the temperature drops below the reference temperature a20, the control unit 207 determines that steam locking has occurred and issues a command to the drive unit 209 to rotate the bypass valve stem 61 in a direction to loosen it. This causes the bypass valve stem 61 to move in the direction of arrow 99 along the axis L1, and the bypass valve element 62 retracts from the bypass valve port 49 (see Figure 7).

As explained in the first embodiment, the opening degree of the bypass valve port 49 changes depending on the slope of the bypass valve body 62, so the control unit 207 can adjust the opening degree of the bypass valve port 49 by controlling the rotation of the bypass valve stem 61.

As shown in Figure 8, the control unit 207 adjusts the flow rate of condensate by controlling the opening of the bypass valve 220 in response to the detected temperature. The state in which the bypass valve element 62 completely closes the bypass valve port 49 (Figure 5) is defined as the valve opening degree of "0%," and the state in which the bypass valve element 62 is completely retracted from the bypass valve port 49 and no longer interferes with the outflow of condensate is defined as the valve opening degree of "100%."

For example, at time "P21," the detected temperature is "a21," which is lower than the reference temperature "a20," and the corresponding valve opening is "75%." Therefore, the control unit 207 issues a command to the drive unit 209 to rotate the bypass valve stem 61 so that the bypass valve port 49 is opened to 75%.

In this way, the condensate is discharged bypassing the bypass pipes 73 and 74 while being controlled by flow rate adjustment, and the steam locking phenomenon is resolved. As a result, high-temperature condensate begins to flow into the steam trap 200, and the temperature detected by the temperature sensor 201 gradually increases, eventually reaching the reference temperature a20 at time point "P22".

In this embodiment, the opening degree of the bypass valve 220 is adjusted in response to the detected temperature, so just before point P22, when the steam locking phenomenon is resolved and the reference temperature a20 is reached, the opening degree of the bypass valve 220 is close to 0%. Therefore, immediately after the steam locking phenomenon is resolved, the bypass valve 220 is closed.

In other words, condensate can be appropriately discharged through bypass pipes 73 and 74 depending on the condensate accumulation status, and bypass valve 220 can be closed immediately when the steam locking phenomenon is resolved, thereby reliably preventing steam leakage when the steam locking phenomenon is resolved.

In addition, in this embodiment, if the steam locking phenomenon occurs, the drain can be automatically and appropriately discharged through the bypass valve 220 depending on the drain accumulation status, thereby more efficiently resolving the steam locking phenomenon.

[Third embodiment]
Next, a third embodiment of a valve system having a locking release function according to the present invention will be described with reference to Figures 9 and 10. The valve system according to this embodiment has a configuration similar to that of the valve system according to the second embodiment. The substantial difference from the second embodiment is the content of the rotation control program for the bypass valve stem 61 executed by the control unit 207 of the actuator 205.

The graph in Figure 9 shows the change in the detected temperature of the drain in the valve chamber 16 as curve x, but in this embodiment, the degree of change in the detected temperature is understood as the slope of the change in curve x, and the opening of the bypass valve port 49 is adjusted according to this slope angle. Figure 10 shows the relationship between the slope angle and the valve opening, and in this embodiment, the slope angle and the valve opening are set to be proportional. The data in Figure 10 showing the relationship between the slope angle and the valve opening is stored in advance in memory 208 of the actuator 205.

As shown in Figure 10, in this embodiment, when the change in curve x is gradual and the slope angle is small, the valve opening is set to a small value, and when the change in curve x is rapid and the slope angle is large, the valve opening is set to a large value.

Specifically, the control unit 207 calculates the center line of the curve x for a predetermined calculation time i3, determines the inclination angle of the center line, and issues a command to the drive unit 209 to rotate the bypass valve stem 61 so that the valve opening corresponds to the inclination angle. Note that during normal operation when steam locking is not occurring, the temperature detected by the temperature sensor 201 indicates a nearly constant high temperature, and the inclination angle of the curve x is "0 degrees," so the opening of the bypass valve 220 is "0%" and the valve remains closed.

When steam locking occurs, the detected temperature drops, and the control unit 207 rotates the bypass valve stem 61 accordingly. For example, for time point "P32" in Figure 9, the curve x of the detected temperature from time point "P32" to time point "P31", calculated time "i3" back, is extracted, and the inclination angle of the center line k1 of curve x during this period relative to the x-axis is calculated.

If the tilt angle is 35 degrees, the corresponding valve opening is 38.9%, as shown in Figure 10. Therefore, the control unit 207 issues a command to the drive unit 209 to rotate the bypass valve stem 61 so that the bypass valve port 49 is opened to 38.9%.

In addition, in this embodiment, the numerical value of the inclination angle of the center line relative to the x-axis is recognized as an absolute value, so the inclination direction of the center line does not affect the recognized inclination angle. For example, for time point "P34," the curve x of the detected temperature from time point "P34" to time point "P33," which is calculated time "i3" back, is extracted, and the inclination angle of the center line k2 of curve x during this period relative to the x-axis is calculated; in this case, the inclination angle is recognized as "30 degrees."

In this way, the condensate is discharged bypassing the bypass pipes 73 and 74 while being controlled by flow rate adjustment, and the steam locking phenomenon is resolved. As a result, high-temperature condensate begins to flow into the steam trap 200, and the temperature detected by the temperature sensor 201 gradually increases, eventually stabilizing at a constant high temperature at time "P35."

In this embodiment, the opening degree of the bypass valve 220 is adjusted in accordance with the inclination angle of the center line of curve x relative to the x-axis, i.e., the degree of change in the detected temperature. Therefore, just before the point "P35" when the steam locking phenomenon is resolved, the inclination angle approaches "0 degrees," and the opening degree of the bypass valve 220 also approaches "0%." Therefore, after the steam locking phenomenon is resolved, the bypass valve 220 can be immediately closed.

In other words, condensate can be appropriately discharged through bypass pipes 73 and 74 depending on the condensate accumulation status, and bypass valve 220 can be closed immediately when the steam locking phenomenon is resolved, thereby reliably preventing steam leakage when the steam locking phenomenon is resolved.

In addition, in this embodiment, if the steam locking phenomenon occurs, the drain can be automatically and appropriately discharged through the bypass valve 220 depending on the drain accumulation status, thereby more efficiently resolving the steam locking phenomenon.

[Other embodiments]
In the above-described embodiment, the float-type steam traps 1, 200 are used as an example of the basic valve, but this is not limited to this. Valves with other configurations can be used as long as they are provided on the basic flow path (such as the inlet pipe 71 and the outlet pipe 72) and block the passage of a fluid (such as steam or drain) when closed and allow the passage of a fluid when opened.

In addition, while the above-described embodiment uses bypass valves 4 and 220 as examples of auxiliary valves, this is not limiting. Other valves may be used as long as they are located in the bypass flow path (bypass pipes 73 and 74, etc.), open in response to a locking phenomenon in which the basic valve (steam trap 1, 200, etc.) cannot open due to fluid (steam, condensate, etc.) stagnating in the basic flow path (inlet pipe 71 and outlet pipe 72, etc.), and allow fluid to pass through the bypass flow path. While the bypass valve 4 is assumed to be normally closed, it may also be slightly open under normal circumstances. By keeping it slightly open, the Venturi effect can be used to promote condensate discharge even when the upstream pressure is low.

In addition, in the above-described embodiment, a conical bypass valve body 62 was used as the valve body portion, and a bypass valve port 49 was used as the auxiliary valve port portion, but this is not limited to these, and other shapes and structures may be used. For example, the valve body portion may be configured in a truncated cone shape rather than a cone shape, and shapes other than a cone shape may also be used.

In addition, in the above-described embodiment, a temperature sensor 201 was used as an example of the detection means, and a temperature signal was used as an example of the detection signal, but this is not limited to this, and other configurations can be used as long as they detect a locking phenomenon (such as steam locking) and output a signal. For example, a vibration detection means could be used that detects drain discharge noise as vibration rather than temperature, and detects a locking phenomenon when the discharge noise is not generated.

1, 200: Steam trap 4, 220: Bypass valve 10: Float
49: Bypass valve port 62: Bypass valve body 71: Inlet pipe 72: Outlet pipe
73, 74: Bypass pipe L1: Axis 201: Temperature sensor

Claims (4)

A basic flow path through which a fluid passes from upstream to downstream.
a basic valve that is provided on the basic flow path and can be opened or closed, blocking the passage of the fluid when closed and allowing the passage of the fluid when opened;
an opening/closing means for closing or opening the basic valve;
a bypass flow path connecting the upstream basic flow path of the basic valve with the downstream basic flow path;
an auxiliary valve that is provided on the bypass flow path and can be opened or closed, and that opens when a locking phenomenon occurs in which the basic valve cannot be opened due to a stagnation state of the fluid in the basic flow path, and allows the fluid to pass through the bypass flow path;
It is equipped with
The auxiliary valve is capable of adjusting the flow rate of the fluid passing through the bypass flow path.
A valve system having a locking release function. 2. The valve system with a locking release function according to claim 1,
The auxiliary valve is
an auxiliary valve port portion through which the fluid passes, the auxiliary valve port portion having a center line disposed along the reference line;
a valve body portion that moves into or out of the auxiliary valve port portion along the reference line and adjusts the flow rate of the fluid passing through the auxiliary valve port portion;
It is equipped with
The length of the valve body portion in the reference line direction is longer than the length of the auxiliary valve port portion in the reference line direction.
A valve system having a locking release function. In the valve system with a locking release function according to claim 1 or 2,
a detection means for detecting the locking phenomenon and outputting a detection signal is provided in the basic flow path;
the auxiliary valve adjusts the flow rate of the fluid passing through the bypass flow path based on the detection signal.
A valve system having a locking release function. In the valve system with a locking release function according to claim 3,
the detecting means is a temperature detecting means for detecting the temperature of the fluid flowing through the basic flow path upstream of the basic valve or the temperature of the fluid flowing into the basic valve.
A valve system having a locking release function.