JPS626151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control valve provided for controlling the flow rate of fuel gas.

Conventionally, as disclosed in Japanese Utility Model Publication No. 55-16172, there is an actuator that supplies pressurized fluid to a pressure chamber using an electromagnetic pressure feeding device and controls the return flow rate to adjust the pressure within the pressure chamber.

However, when the above actuator is applied to a control valve that controls the flow rate of fuel gas supplied to various types of gas combustors, if the flow rate falls below the minimum value determined by the characteristics of the burner, the turn
It is necessary to solve problems such as the occurrence of phenomena such as down and the inability to maintain normal combustion conditions, resulting in dangerous conditions such as the release of unburned gas.

The present invention has been made to solve the above-mentioned problems, and is provided with an actuator that controls a valve body by the pressure of fluid pumped by an electromagnetic pumping device. It is an object of the present invention to provide a control valve that controls the supply flow rate so that it does not fall below a predetermined minimum value.

In order to achieve the above object, the present invention provides an actuator that includes an electromagnetic force-feeding device for force-feeding fluid to a pressure chamber, a responsive body that senses the pressure in the pressure chamber and displaces the pressure, and a gap between an inlet passage and an outlet passage. a valve body for changing the opening area of the port according to the displacement of the responsive body, a pressure sensor for detecting the pressure in the outlet passage, and a set value given from the outside and an output signal of the pressure sensor. and a drive circuit that generates an output signal to drive the actuator, and the drive circuit includes an arithmetic control circuit that generates an output signal corresponding to the difference between the set value and the output signal of the pressure sensor. , and a minimum setting pressure limiting circuit that generates a predetermined constant minimum output signal when the output signal of the pressure sensor is below a predetermined value.

The actuator drive circuit in the present invention generates an output signal corresponding to the difference between a set value given from the outside and an output signal of a pressure sensor that detects the pressure in the outlet passage, and the output signal of the pressure sensor is set to a predetermined value. In the following cases, by generating a predetermined minimum output signal from the minimum set pressure limiting circuit to drive and control the actuator, the flow rate of fuel gas supplied from the outlet passage to the burner is kept below a predetermined minimum value. This prevents this from occurring and safely maintains normal combustion conditions.

Next, an embodiment of the present invention will be described with reference to the drawings. The valve body designated by reference numeral 1 in FIG. ,
The pressure of the fuel gas in the outlet passage 4 is controlled. In order to detect this pressure, a pressure sensor 6 is provided which generates an output signal corresponding to the pressure within the output passage 4.

The actuator 2 is an electromagnetic pump 2 housed in a casing 21, as shown in detail in FIG.
It has 2. This electromagnetic pump 22 receives a drive signal supplied to a coil 23 from a drive circuit 8 to be described later, and operates a first chamber 2 formed in a casing 21.
The liquid (e.g. oil) contained in the second
The pressure in the second chamber 25 causes the pressure in the second chamber 25 to displace a responsive body 27 connected to the valve body 1 via a rod 26. Further, a communication passage 28 is provided for returning the fluid in the second chamber 25 to the first chamber 24, and a predetermined resistance is applied to the fluid flowing through the communication passage 28 by an orifice 29. .

Therefore, when a drive signal is supplied from the drive circuit 8, the electromagnetic pump 22 pumps the liquid in the first chamber 24 to the second chamber 25 to increase the internal pressure.
Sensing this increase in pressure, the responsive body 27 moves downward in the figure. This movement of the responsive body 27 causes the valve body 1 to descend against the spring 7, thereby increasing the opening area of the port 5. Further, when the pressure in the second chamber 25 decreases, the valve body 1 rises together with the responsive body 27 due to the action of the spring 7, thereby reducing the opening area of the port 5. This movement of the valve body 1 controls the gas pressure within the outlet passage 4, and this gas pressure is detected by the pressure sensor 6. Under normal conditions, gas pressure is proportional to the gas supply flow rate.

FIG. 3 shows another form of actuator 2 applicable to the present invention. In this example, an electromagnetic compressor 32 for pumping air into a pressure chamber 31 corresponding to the second chamber 25 is used instead of the electromagnetic pump 22 shown in FIG. This electromagnetic compressor 32 has a coil 33 to which a drive signal is supplied, and a cylindrical body 35 that supports a plunger 34 that reciprocates at the center of the coil 33. A piston 36 movable within a cylinder 35 is connected to the plunger 34.
By the reciprocating motion of 6, the inside of the cylinder chamber 37 formed in the cylinder 35 is alternately pressurized and depressurized. This cylinder chamber 37 has a check valve 38 and a check valve 38, respectively.
The suction chamber 40 communicates with a suction chamber 40 and a discharge chamber 41 containing a
Further, the discharge chamber 41 is connected to the pressure chamber 31 through the communication hole 43.
are connected to each other. The discharge chamber 41 also includes a passage 44 having a flow rate restricting means such as an orifice.
It also communicates with the outside via. Further, the check valve 38 is pressed by a spring 45 in the direction of closing the suction hole 42, and the check valve 39 is pressed by the spring 46 in the direction of closing the passage between the cylinder chamber 37 and the discharge chamber 41. There is.

A plunger 34 and a piston 36 connected thereto are driven by a drive signal supplied to the coil 33.
When the pressure chamber 31 reciprocates, air sucked through the suction hole 42 is forced into the pressure chamber 31, and the pressure inside the chamber 31 increases. That is, when the piston 36 moves upward in FIG. Air is inhaled. Also piston 36
In the process of descending, the air in the cylinder chamber 37 and the suction chamber 40 is compressed, so the check valve 38 is held in the position where the suction hole 42 is closed.
The check valve 39 moves against the spring 46 and opens a passage between the cylinder chamber 37 and the discharge chamber 41. As a result, the air in the cylinder chamber 37 is
Pressure chamber 31 through exhaust chamber 41 and communication hole 43
A portion of the fluid flows into the interior and a portion is discharged to the exterior through the passage 44. When the pressure inside the pressure chamber 31 increases due to this operation, the responsive body 27 is pushed down, and the valve body 1 connected to the responsive body 27 via the rod 26 moves in the opening direction, as in the case of FIG. .

A drive circuit 8 for supplying a drive signal to the actuator 2 includes an arithmetic control circuit 9, a minimum set pressure limiting circuit 10, and a maximum set pressure limiting circuit 11.
The arithmetic control circuit 9 accepts set values given from the outside.
Based on the output of a comparator 12 that compares SP with the output signal of the pressure sensor 6, an output signal corresponding to this output is generated, and this output signal is supplied to the actuator 2 as a drive signal.

The output signal of the pressure sensor 6 is also simultaneously supplied to the minimum set pressure control circuit 10 and the maximum set pressure control circuit 11. The minimum set pressure control circuit 10 reduces the pressure to the minimum value when the pressure in the outlet passage 4 becomes lower than a predetermined minimum value due to the set value SP being set to a significantly low value. A drive signal necessary for maintenance is supplied to the actuator 2.
This minimum value is preset to a value that does not cause the burner to turn down, depending on the characteristics of the burner supplied with fuel gas through the outlet passage 4. However, when the source pressure decreases and the minimum pressure cannot be achieved even if the valve body 1 is opened, the valve body 1
becomes inactive. On the other hand, the maximum set pressure control circuit 11
is a drive that limits the pressure in the outlet passage 4 to a predetermined value when the pressure in the outlet passage 4 becomes higher than a predetermined maximum value due to the set value SP being set to a significantly high value. The signal is supplied to the actuator 2 with priority over the output of the arithmetic control circuit 9. This prevents the danger of supplying too much fuel gas to the burner, but in cases where the maximum pressure is limited, for example by a regulator.
The maximum set pressure limiting circuit 11 can be omitted.

As described above, according to the present invention, no matter how the set value is changed, the flow rate of the fuel gas supplied to the burner from the outlet passage 4 will never fall below a predetermined minimum value, and for example, the It is also safe to control combustion manually using, for example,

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view including a block diagram showing the configuration of a control valve according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of an actuator used in the control valve of FIG. 1, and FIG. FIG. 3 is a longitudinal sectional view of the actuator of FIG. 1... Valve body, 2... Actuator, 3... Inlet passage,
4... Outlet passage, 5... Port, 6... Pressure sensor, 8
...Drive circuit, 9...Arithmetic control circuit, 10...Minimum setting pressure limiting circuit, 11...Maximum setting pressure limiting circuit, 12...
Comparator, 22... Electromagnetic pump, 23... Coil, 24
...1st room, 25...2nd room, 26... Rod, 27...
Response body, 31...pressure chamber, 32...electromagnetic compressor, 33...coil, 36...piston.

Claims (1)

[Claims] 1. An electromagnetic pressure-feeding device for force-feeding fluid to a pressure chamber, an actuator equipped with a responsive body that senses the pressure in the pressure chamber and displaces it, and an opening area of a port between an inlet passage and an outlet passage. a valve body for changing the pressure in accordance with the displacement of the responsive body; a pressure sensor for detecting the pressure in the outlet passage; a drive circuit that generates an output signal for driving the pressure sensor; A control valve comprising a minimum set pressure limiting circuit that generates a predetermined minimum output signal when the output signal is below a predetermined value. 2. The drive circuit further comprises a maximum setting pressure limiting circuit that generates a predetermined maximum signal when the output signal of the pressure sensor becomes larger than a predetermined value. The control valve according to item 1.