JPS62283276A - Flow amount adjusting method for valve - Google Patents

Abstract

PURPOSE:To enable a delivery flow amount to be remotely controlled, by controlling pressure force of a working medium, given to a valve unit, through the pressure force of fluid acting on the valve unit. CONSTITUTION:A diaphragm type valve 2 is developed for automatic irrigation, and the valve 2 provides its working medium derivation inlet to be not arranged directly to a pressure chamber 5 in the back part of a diaphragm 4 but formed in a cylinder chamber 13 behind a piston 15 longitudinally moving in a cylinder 16. The piston 15 and a spring 14 are provided to be arranged in the cylinder 16 generating force separating the piston 15 and the diaphragm 4 from a valve seat 3. Air is used as a pressure medium, and its pressure is regulated by a solenoid valve. If assumed Q for force by this pressure, P for force of fluid acting on a valve unit and R for force of spring tension, the force Q is controlled so that a relation, where Q=P+R, is obtained.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for adjusting the opening degree of a fluid discharge valve whose opening and closing are controlled by introducing and injecting a working medium. The present invention relates to a method for adjusting the flow rate 4i of a valve, which allows accurate remote control of the opening degree of the valve even when the pressure of the discharged fluid varies minutely.

[Prior Art] The present applicant has already filed applications such as U.S. Pat. No. 60-67496 and U.S. Pat.

FIG. 2 is an explanatory cross-sectional view showing a diaphragm valve 2 for supplying or stopping the supply of irrigation water flowing through the water pipe 1 to areas where irrigation is required (for example, between ridges). When the control working medium is pressurized in the direction of arrow A from the working medium inlet to fill the pressure chamber 5 with high pressure, the diaphragm 4 is pressed against the valve seat 3 side by the pressure (at the position indicated by the broken line in the drawing). ) The intake of irrigation water from the water intake is shut off at the valve seat 3. Conversely, when the working medium is released from the pressure chamber 5 and the diaphragm 4 is retreated from the valve seat 3 (solid line position in the drawing), irrigation water flows into the valve from the water intake along the arrow Wa and is further released. It is discharged to the outside from the exit along the arrow wb. In addition, adjustment screw 8
is to move the stopper 9 8 times to the left and right of the drawing,
The amount of irrigation water when the diaphragm 4 is fully opened is adjusted.

[Problems to be solved by the invention] The water pipe 1 shown in FIG. 2 is connected to a reservoir that is a water source,
Various efforts are made to ensure a constant flow rate at all times. However, the amount of water stored in the reservoir shown by the solid line is the input amount (
Precipitation) and output volume (irrigation supply volume, evaporation volume, etc.) fluctuate on a daily basis and are not constant, and when focusing on a particular diaphragm valve 2, the amount of irrigation water flowing out from the valve also varies. There is a risk that this may occur. Despite this danger, if valve 2 were to be controlled only in the two positions of fully open and fully open, the amount of water supplied would be different, which could deviate significantly from the designed amount, and in severe cases. may have a negative effect on crop growth. Therefore, in order to eliminate such variations in the amount of water supplied, a method has been adopted in which valves 2 installed in the field are capable of adjusting the opening, and the operator turns the valve by adjusting the opening each time. There is. However, workers are forced to walk around the vast fields, making them very inefficient.

The present inventors focused on this situation and developed a method that allows the amount of fluid discharged from a valve to be adjusted by remote control, and also allows the selection of an appropriate valve opening degree even when the pressure of the fluid being discharged fluctuates. As a result of various researches aimed at developing this method, we have completed the method of the present invention.

[Means for Solving the Problems] The method of the present invention, which has achieved the above object, reduces the force of the fluid acting in the direction of pushing the valve body away from the valve seat, P, and the force of the fluid acting in the direction of pushing the valve body toward the valve seat side. When the force of the working medium acting is Q,
A spring is connected to the valve body and acts in a direction to move the valve body away from the valve seat, and the force of the spring is R, and Q=P+R.
The gist of this method is that it is a method of adjusting the flow rate of fluid discharged from a valve seat by controlling Q so as to satisfy the following equation.

[Function] The valve applied to the method of the present invention has the following (1) to (5).
The conditions shown in section 1.

(1) Fluid is discharged through the opening of the valve seat, and the fluid discharge is stopped by bringing the valve body into contact with the valve seat, and conversely, the fluid is discharged by separating the valve body from the valve seat. be allowed.

(2) The discharge flow rate from the valve seat can be adjusted by adjusting the distance S between the valve seat and the valve body (see FIG. 1).

(3) The valve body must be pressed against the valve seat by the pressure Q of the working medium.

(4) The fluid discharged from the valve seat should exert a force P in the direction of moving the valve body away from the valve seat.

(5) A spring is connected to the valve body, and the force of the spring applies a force R to the end of the valve that causes the valve body to move away from the valve seat.

Using a valve that satisfies the above conditions, the distance S between the valve body and valve seat
It was found that the force P from the discharged fluid gradually decreased from fully closed to fully open, as shown by the curve P in FIG. 3 (the broken line Pa will be described later). That is, in the fully closed state, the maximum force P0 acts on the valve body, and as the distance S increases from fully closed to fully open, the amount of fluid released from around the valve body (that is, the amount of fluid that does not act on the valve body) increases. As a result, the force P that attempts to push the valve body away from the valve seat is gradually reduced.

Also, a spring (tension spring in Fig. 1) 14 connected to the valve body
As shown by the straight line R in FIG. 3, the force R exerted on the valve body decreases as the distance S increases. That is, the distance S and the force R
is inversely proportional.

For example, in the graph shown in FIG. 3, if the distance between the valve seat and the valve body is currently fixed at point S1, the force that tends to move the valve body away from the valve seat is the sum of R1 and Pl. On the other hand, the force Q of the working medium that acts to press the valve body against the valve seat is equal to the sum of R1 and Pl, and Q+
=P+ +R+1, and it can be seen that the discharge flow rate of the fluid in this state is determined by the relationship between the fluid pressure P and the spacing S. It is also understood that since the spring force R is determined by the state of extension of the spring and cannot be controlled from outside the system, it must be controlled by adjusting Q.

On the other hand, if the discharge fluid flow rate in the state of the interval S is insufficient and the required flow rate cannot be obtained unless the interval S is increased to S2, then the value of the sum of forces (P2 + R2) determined by R2 and P2 at S2 is determined by a graph or calculation, and the force Q of the working medium is changed to Q2 so that p2 +R2''Qz.

In other words, by manipulating the force Q of the working medium to balance the sum of the force R of the spring and the force P of the fluid, the distance S between the valve seat and the valve body can be set to a desired value, and the pressure of the discharged fluid and the distance S This means that the fluid flow rate determined by can be adjusted arbitrarily. At this time, it is theoretically possible to adjust the position of the valve body only by balancing the force P of the fluid and the force Q of the working medium without providing a spring, but as shown in Figure 3, the curve P is gentle. The pressure of the working medium required for this slope must be adjusted with precision. On the other hand, when a spring R is provided, the sum of P and R shows a steep curve Q, and it is understood that fluctuations in the interval S due to pressure adjustment errors of the working medium Q are reduced, improving control accuracy. be done.

In addition, when controlling the force Q of the working medium, it can be operated near the pressure source by using a regulator, etc., so even if the valve is located far away from the pressure source, it can be centrally controlled remotely. It becomes possible.

[Example] Figure 5s is a cross-sectional explanatory diagram showing an example of a diaphragm type valve 2 developed for automatic irrigation. The structural differences from the valve shown in FIG. 2 are as follows.

That is, the working medium outlet/inlet is not disposed directly in the pressure chamber 5 at the back of the diaphragm 4, but rather in the cylinder chamber 13 corresponding to the rear of the piston 15 moving back and forth within the cylinder 16.
The working medium is formed as a working medium derived population 12. cylinder 16
A piston 15 that is slidable along the inner wall is provided inside the piston 15, and a diaphragm 4 and a stopper 9 are fixedly attached to the tip of the piston 15. A tension spring 14 is disposed so as to extend roughly between the piston 15 and the rear wall of the cylinder 16, and generates a force in the direction of separating the piston 15 and the diaphragm 4 from the valve seat 3.

In this way, a force is applied to the diaphragm 4 by the force P of the discharged fluid and the force R of the tension spring 14 to move it to the right in the drawing, and on the other hand, by introducing the working medium from the direction of arrow A, the diaphragm 4 is moved 8 to the left in the drawing. Generates a force Q that forces you to do so.

Figure 4 shows the working medium (compressed air) used when a large number of diaphragm valves 2 shown in Figure 1 are installed in a field.
It is a schematic explanatory diagram showing an example of a supply source. In addition, solid lines in the figure indicate pipe lines, and broken lines indicate control system lines. Air, which is a working medium, is pressurized by a compressor 20, made constant by a regulator 21, and supplied to solenoid valves 25a, 25b and a distributor 26 for closing the diaphragm valve 2 in the field. Compressed air is distributed and supplied by selecting only two groups of diaphragm valves that are bent to the block for supplying compressed air for closing tilt. In addition, a part of the compressed air is supplied to the electro-pneumatic regulator 22 to adjust the pressure, and then supplied to the electro-6u valves 25a and 25b, and a part of the compressed air is sent to one of the blocks in the field via the distributor 26. It is fed to valve 2.

The switching of the Z&H valves 25 a and 25 b to open and close the valve 2 and the setting of the compressed air pressure in the electropneumatic regulator 22 are controlled by the controller 23.
The water head value in the reservoir 27 is input to the controller 23 .

To explain the operation of the T and magnetic valves 25a and 25b shown in FIG. valves to completely close the valves. On the other hand, compressed air whose pressure has been regulated by the electropneumatic regulator 22 is passed through the 'rL magnetic valve 25b, and the distributor 2
Two groups of valves belonging to any one of the blocks communicated through the valve 6 are set to an appropriate opening degree and opened. For example, if the inner diameter of the valve seat 3 of the valve 2 shown in Fig. 1 is 46a1m,
The relationship between the water head of the irrigation water supplied to the valve 2 and the amount of water discharged from the valve seat 3 is calculated as shown in FIG. 5 (graph) in consideration of the relationship with the interval S. That is, in a block where the water head of the reservoir 27 is 1.0 m and supplies irrigation water, approximately 60 Jl/+ is generated from one valve 2.
If you want to supply water at a rate of 9.9mm, it is sufficient to set the above-mentioned interval S between 2 and 4mm, and as a result of more detailed calculations, it was found that S should be set at 2.4mm. .

Figure 6 shows the force Q balanced at the distance S when the spring tension constant is 4.6 kg/cm and the water head changes.
(Including the air pressure per unit area, however, the inner diameter of the cylinder 16 is 28 mm).The diagonal line starting from the number written on the vertical axis on the right side of the graph is the force Q of compressed air. corresponds to That is, in the previous example, when setting the interval S to 2.4 mm, obtain the intersection point B with the graph of R + 1 m, read the air force from the value on the left side of the graph, and obtain the air pressure of approximately 1.1 Kg/cm. In the diagram shown in FIG. 4, if the set value of the electropneumatic regulator 22 is set to 1.1 Kg/cm2, under the condition of a water head of 1 m, a flow rate of 601/ff1 inch is obtained from valve 2 in the block communicating with the 7f111 valve 25b. Irrigation water can now be discharged.

Furthermore, 60 fl/min and 1501/min shown in Figure 6
The min curve shows the approximate lower and upper limits of use for the diaphragm valve 2, and the range surrounded by this graph can be said to be the applicable range of flow rate adjustment of the valve 2.

FIG. 7 is a flowchart showing what operations are performed to keep the amount of water discharged from the valve 2 constant when the water head of the reservoir rises or falls. That is, when the water head of the reservoir rises, the diaphragm 4 of the diaphragm valve 2 shown in FIG. Put it away. In order to suppress this increase, it is necessary to increase the air pressure of the compressed air and move the diaphragm 4 toward the valve seat 3 by an appropriate amount, thereby making it possible to obtain a water pressure equivalent to the flow rate before the water head rises. In other words, from the increased water head value and the desired water volume, calculate the appropriate spacing S between the valve seat 3 and the diaphragm 4 based on the graph in FIG. The controller 23 shown in FIG. 4 controls the voltage regulator 22 to increase the compressed air pressure to a predetermined value.

In this way, the interval S is set to an appropriate value to maintain the same flow rate as before the water head rose. On the other hand, even when the water pressure decreases, similar control is performed to automatically control the valve 2 so that a constant flow rate is always ensured.

Furthermore, in a vast field, it is conceivable that the flow rate from the valve 2 becomes uneven due to differences in the head loss of irrigation water between the field blocks near the reservoir and the field blocks far away. Therefore, in order to solve this problem, the water pressure force P value is corrected in advance as shown by the broken line Pa in Figure 3, and the Q value is changed so as not to cause a difference in flow rate, or the value is provided in valve 2. By using means such as changing the spring constant of the tension spring 14, water is uniformly supplied to the entire field.

The flow rate adjustment method of the present invention is not only applicable to the automatic irrigation valve shown in the above example, but can also be similarly applied to valves used in other fields that utilize fluids.

[Effects of the Invention] By using the method of the present invention, it becomes possible to adjust the discharge flow rate from the valve by remote control, and even if the pressure of the discharge fluid changes, the fluid flow rate can be accurately controlled in response to this. Now I can do it. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram showing an example of a valve used in the method of the present invention, FIG. 2 is a cross-sectional explanatory diagram showing an example of a diaphragm type valve, and FIG. Graph, FIG. 4 is a schematic explanatory diagram showing an embodiment of the working medium supply source used in the method of the present invention, FIG. 5 is a graph showing the relationship between fluid water pressure and flow rate at interval S, and FIG. FIG. 7 is a graph showing the relationship between and working medium pressure (air pressure), and FIG. 7 is a flowchart showing the operation for keeping the valve discharge amount constant. 1... Water pipe 2... Diaphragm type valve 3... Valve seat 4... Diaphragm 5...
...Pressure chamber 6...Packing 8...Threaded part 9...Stopper 10...Discharge port
11... Handle 12... Working fluid inlet/outlet pipe 13... Cylinder chamber 14... Retraction spring 15.
... Piston 16 ... Cylinder 20 ... Compression @ 21 ... Regulator 22 ... Electropneumatic regulator

Claims (1)

[Claims] In a method of adjusting the flow rate of fluid discharged from the valve seat by changing the gap between the valve seat and the valve body, P is the force of the fluid that acts in the direction of pushing the valve body away from the valve seat, and P is the force of the fluid that acts in the direction of pushing the valve body away from the valve seat, and When the force of the working medium acting in the pressing direction is Q, a spring connected to the valve body and acting in a direction to move the valve body away from the valve seat is provided, and the force of the spring is R, and Q=P.
A method for adjusting the flow rate of a valve, characterized in that the flow rate of fluid discharged from the valve seat is adjusted by controlling Q so as to satisfy the formula +R.