JPS6225909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate control device that automatically controls the flow rate of various fluids according to the amount of demand.

Generally, in flow control devices, such as water heaters,
The flow rate of fuel supplied to the burner needs to be controlled depending on the magnitude of the heat demand. In other words, a conventional general flow control device includes an electromagnetic pump that pumps pressure fluid in an actuator from a first pressure chamber to a second pressure chamber, and a response device that senses pressure fluctuations in the second pressure chamber and displaces the fluid. and a valve body that is connected to the response body via a rod and that changes the size of the opening of a port formed between the inlet passage and the outlet passage of the fluid to be controlled. The flow rate is controlled by comparing the temperature of the water with the desired hot water setting value using a comparator, and adjusting the opening degree of the valve body according to the difference between the two. be.

However, in such conventional flow control devices, even if the opening degree of the valve body remains the same, if the pressure on the secondary side of the valve body fluctuates for some reason, the flow rate will change accordingly, so it is not practical. There was a problem in that the flow rate of fuel supplied to the engine did not correspond to the magnitude of the heat demand.

This invention was made to solve the above problems, and has a function that automatically adjusts the opening degree of the valve body when the pressure on the secondary side of the valve body fluctuates to compensate for this fluctuation. An object of the present invention is to provide a flow control device having the following features.

In order to achieve the above object, the present invention provides an electromagnetic pressure-feeding device for force-feeding fluid in an actuator from a first pressure chamber to a second pressure chamber, and detects pressure fluctuations in the second pressure chamber. A valve body that controls the flow rate of the controlled fluid flowing from the inlet passage to the outlet passage is connected to the displacing response body, and the output signal of the pressure sensor that detects the pressure in the outlet passage and the heat that indicates the magnitude of the heat request are connected to the displacing response body. Provide a comparator to compare with the request signal,
A pilot valve that adjusts the resistance given to the fluid returning from the second pressure chamber to the first pressure chamber via the communication path according to the deviation from the comparator, and adjusts the pressure in the second pressure chamber. is interposed in the communication path.

Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a valve body designated by reference numeral 1 changes the size of the opening of a port 5 formed between an inlet passage 3 and an outlet passage 4 according to the position regulated by an actuator 2. The pressure of the fuel gas in the outlet passage 4 is thereby controlled. In order to detect this pressure, a pressure sensor 6 is provided which generates an output signal corresponding to the pressure within the outlet passage 4.

Actuator 2 has an electromagnetic pump 22 housed within a casing 21 . This electromagnetic pump 22 receives a drive signal supplied to a coil 23 from a drive circuit (not shown), and pumps a liquid (for example, oil) contained in a first pressure chamber 24 formed in the casing 21 into a second pressure chamber 24. The pressure inside the second pressure chamber 25 causes the response body 27 connected to the valve body 1 via the rod 26 to be displaced. Further, a communication passage 28 for returning the fluid in the second pressure chamber 25 to the first pressure chamber 24 is provided, and this communication passage 2
A pilot valve 20, which will be described later, is connected to the fluid flowing through the
A predetermined resistance is provided by .

Therefore, when a drive signal is supplied from the drive circuit, the electromagnetic pump 22 pumps the liquid in the first pressure chamber 24 to the second pressure chamber 25 to increase the internal pressure, and this increase in pressure Detecting the response body 27
moves down the diagram. 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, if the pressure inside the second pressure chamber 25 decreases, the valve body 1 moves to the response body 2.
7 and rises 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 amount of gas supplied.

The gas flowing from the inlet passage 3 through the port 5 into the outlet passage 4 is supplied to the burner 8 through normal piping and is used as fuel for heating the heat exchanger 9. Further, a temperature sensor 10 is provided to detect the temperature of water in the heat exchanger 9.

The comparator 11 detects the difference between a set value SP indicating the desired hot water temperature to be obtained and a detected value indicating the actual temperature of the water in the heat exchanger 9 detected by the temperature sensor 10, that is, the heat An output signal corresponding to the magnitude of the request is generated, and this heat request signal is sent to the signal conversion circuit 1.
After undergoing predetermined signal processing at step 2, the signal is sent to the second comparator 13. This comparator 13 has a function of comparing the output of the signal conversion circuit 12 and the output signal of the pressure sensor 6, and sending an output corresponding to the difference to the control circuit 14. That is, the output of the second comparator circuit 13 corresponds to the difference between the magnitude of the heat demand and the gas pressure in the outlet passage 4, that is, the flow rate of the fuel gas supplied to the burner 8, and the control circuit 14 A control signal corresponding to the control signal is supplied to the pilot valve 20.

The pilot valve 20 has a coil 15 to which a DC control signal from the control circuit 14 is supplied, and a plunger 16 that is movable in the axial direction at the center of the coil 15. One end of this plunger 16 is
A valve body 18 is supported via the diaphragm 17, and the opening area of a passage 19 communicating with the second pressure chamber 25 of the actuator 2 via a communication passage 28 is adjusted depending on the position of the valve body 18. That is, the pilot valve 20 adjusts the amount of resistance given to the fluid returning from the second pressure chamber 25 to the first pressure chamber 24 through the communication path 28 in accordance with the control signal supplied from the control circuit 14. As a result, the pressure within the second pressure chamber 25 is adjusted, thereby controlling the opening degree of the valve body 1.

FIG. 2 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 pressure chamber 25 is used instead of the electromagnetic pump 22 shown in FIG. This electromagnetic compressor 32 includes 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.
It has The plunger 34 has a cylindrical body 35
A movable piston 36 is connected therein, and the reciprocating motion of the piston 36 alternately pressurizes and depressurizes the inside of a cylinder chamber 37 formed within the cylinder body 35. This cylinder chamber 37 communicates with a suction chamber 40 and a discharge chamber 41, each of which has a built-in check valve 38, 39. Each of them communicates with the pressure chamber 31. Also, the discharge chamber 4
1 also communicates with the outside via a passage 44 having a flow restriction means such as an orifice. 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 discharge 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 is moved in the opening direction, as in the case of FIG. .

As described above, according to the present invention, the position of the valve body 1 is automatically controlled so that the pressure in the outlet passage 4 is always at a desired constant value, and this value is determined based on the set temperature and the load temperature. determined by the heat demand signal, which is the difference between Therefore, gas is supplied to the burner 8 at a flow rate commensurate with the actual heat demand.
The load temperature is accurately maintained at the set temperature. Further, the opening degree of the valve body 1 is controlled by a pilot valve 8 that operates based on a heat request signal.
This is done by adjusting the amount of resistance given to the fluid flowing out from 5, so the opening degree of the valve body can be automatically adjusted to compensate for pressure fluctuations on the secondary side of the valve body, thus improving responsiveness. This has the effect of greatly improving control accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a flow control device according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing another actuator used in the flow control device of the present invention. DESCRIPTION OF SYMBOLS 1... Valve body, 2... Actuator, 3... Inlet passage, 4... Outlet passage, 6... Pressure sensor, 8
... Burner, 9 ... Heat exchanger, 10 ... Temperature sensor, 11 ... Comparator, 12 ... Signal conversion circuit, 1
3... Comparator, 14... Control circuit, 15... Coil, 16... Plunger, 17... Diaphragm, 18... Valve body, 19... Passage, 20... Pilot valve, 22... Electromagnetic pump, 23... Coil, 24... First chamber, 25... Second chamber, 27...
Response body, 28... Communication path, 31... Pressure chamber, 32
...Electromagnetic pump, 33...coil, 36...piston.

Claims (1)

[Claims] 1. An electromagnetic pressure-feeding device that force-feeds fluid in the actuator from a first pressure chamber to a second pressure chamber, a responsive body that senses pressure fluctuations in the second pressure chamber and displaces, and a Accordingly, the valve body changes the size of the opening of the port formed between the inlet passage and the outlet passage, and controls the flow rate of the controlled fluid flowing from the inlet passage to the outlet passage, and the pressure in the outlet passage is controlled. The pressure sensor to be detected compares the output signal of this pressure sensor with a heat request signal indicating the magnitude of the heat request, and depending on the deviation, the pressure is transferred from the second pressure chamber to the first pressure chamber via the communication path. and a pilot valve that adjusts the resistance given to the fluid to be returned to the flow rate and the pressure inside the second pressure chamber.