JPH0240154B2 - ATSURYOKUHIREISEIGYOBEN - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is used in gas combustion appliances, etc., and continuously controls the outlet side gas pressure (flow rate) according to the combustion load signal, that is, the hot water temperature, room temperature, etc. , relates to a pressure proportional control valve for obtaining a desired temperature.

BACKGROUND OF THE INVENTION Since the supply pressure of fuel gas fluctuates, a gas governor is required to absorb this fluctuation. For this reason, some gas governors have a proportional control function and a governor function by varying the set force of the gas governor using electromagnetic force. (For example, Japanese Utility Model Publication No. 55-126072, Japanese Utility Model Publication No. 59-134175) Conventional pressure proportional control of this type is shown in FIGS. 4 and 5. In FIG. 4, reference numeral 1 denotes a governor section including a valve body 2, a valve seat 3, a diaphragm 4 provided on the valve body 2, and a spring 5 provided to cancel the self-weight of the valve body 2, 6 a permanent magnet 7, a center It is a drive unit having a coil bobbin 11 on which a pole 8, a yoke 9, and a coil 10 are wound, and which is provided on the center pole 8 so as to be able to move up and down.By energizing the coil 10, the coil bobbin 11 is moved according to Fleming's left hand rule. An electromagnetic force is generated that displaces the governor downward, and the governor setting force is varied. This drive unit 6 is characterized in that an electromagnetic force proportional to the amount of energization can be obtained, and that the electromagnetic force does not change even if the coil bobbin 11 is displaced when the amount of energization is constant.

FIG. 5 shows another conventional example, in which a valve body 13 equipped with a permanent magnet 12 as a magnetic body, and a valve body 13 equipped with a permanent magnet 12 as a magnetic body.
It has a fixed iron core 14 disposed close to the permanent magnet 12, a coil 15 that generates a magnetic force in a direction repelling the permanent magnet 12, and a coil 15 that biases the valve body 13 to close in response to pressure from the fluid inlet 16. A diaphragm 17 is provided, and by controlling the current applied to the coil 15, the electromagnetic repulsion force is controlled and the governor setting force is varied. Reference numeral 18 denotes a coiled spring that biases the valve body 13 to close.

In this drive unit 6', when the valve body 13, that is, the permanent magnet 12, is displaced while the amount of current flowing through the coil 15 is constant, the electromagnetic force changes in proportion to the square of the air gap between the permanent magnet 12 and the fixed iron core 14. .

These conventional examples have a problem in that the influence of the diaphragms 4, 17, spring 5, and coil spring 18 appears on the governor characteristic, which is one of the basic performances of the pressure proportional control valve. This point will be explained with reference to FIGS. 6 to 8.

Figure 6 shows the amount of displacement of the valve bodies 2 and 13 when a predetermined amount of current is applied to the coils 10 and 15.
FIG. 12 is a characteristic diagram showing the relationship between X _V and the suspension valve opening under electromagnetic force _n , and the relationship between the valve body displacement amount X _V and the total deflection force F _k of the diaphragms 4 and 17, the spring 5, and the coil spring 18. As mentioned above, in the conventional example in FIG. 4, the electromagnetic force F _n does not change and remains constant even if the valve body 2 is displaced, as shown in the characteristic A, and in the conventional example in FIG. 5, as shown in B, When the valve body 13 displaces, the air gap between the permanent magnet 12 and the fixed iron core 14 increases, so as the valve body 13 displaces, the electromagnetic force increases.
F _n decreases.

Figure 7 shows the amount of displacement of the valve body X _v and the governor setting force F _g ,
That is, it is a characteristic diagram showing the relationship between the forces that substantially act on the valve bodies 2 and 13, and here shows the difference between the electromagnetic force F _n and the deflection force F _k . As can be seen from Fig. 7, in the conventional example in Fig. 4, the deflection force F _k of the diaphragm 4 and spring 5 directly influences the change in the governor setting force F _g , as shown at A', and in the conventional example in Fig. 5, B' Both the deflection force F _k and the change in electromagnetic force F _n affect the governor setting force F _g as shown in FIG.

FIG. 8 shows governor characteristics showing the relationship between the primary pressure P ₁ on the fluid inlet side and the secondary pressure P ₂ on the fluid outlet side. The valve opening degree is automatically adjusted as the primary pressure P ₁ changes, but when the primary pressure P ₁ increases, the secondary pressure P ₂ increases, displacing the valve bodies 2 and 13 upward. As the valve body displacement amount Xv decreases, the governor setting force Fg increases, and conversely, when the primary pressure _P1 decreases, the valve body displacement amount Xv increases and the governor setting force Fg decreases. Therefore, as shown in A'' and B'', the characteristic increases with respect to the ideal characteristic C. This tendency has a particularly large effect when used as a low calorific value gas fuel that requires a large valve opening.

Fig. 4 In order to improve the governor characteristics in the conventional example, the spring constants of the diaphragm 4 and the spring 5 can be made as small as possible, but there is a limit to practical use, and the valve closing force of the spring 5 must be made large. In this case, a large setting force can be obtained with a small spring constant, which leads to an increase in the size of the spring 5.

In addition, in the conventional example shown in FIG. 5, the air gap between the permanent magnet 12 and the fixed iron core 14 is increased, and the electromagnetic force F _n
Although this can be improved by reducing the change in , the magnetic flux density between the air gaps decreases, leading to an increase in the size of the coil 15.

Problems to be Solved by the Invention As described above, the conventional example has a problem in that the diaphragm, spring, and coil spring adversely affect the governor characteristics of the pressure proportional control valve.

Means for Solving the Problems The present invention has been made in view of the above-mentioned conventional problems, and aims to perform proportional control, obtain good governor characteristics, and downsize the drive section. do.

The pressure proportional control valve according to the present invention for achieving this purpose operates in response to a valve seat provided between a fluid inlet and a fluid outlet, a valve body, and a fluid pressure provided integrally with the valve body. A governor portion comprising a diaphragm, a biasing element that biases the valve body to close, a coil, a fixed magnetic body, and a plunger that operates the valve body by an electromagnetic force generated by energizing the coil. a plunger-type drive unit consisting of: a rate of change of electromagnetic force k _fn with respect to the displacement of the plunger; and a rate of change of the deflection force of the diaphragm and biasing element with respect to the displacement of the valve body.
The configuration is such that kε is approximately matched so that the governor setting force is constant.

Effect With this configuration, when the primary pressure (fluid supply pressure) changes and the relative position of the plunger with the coil and the fixed magnetic body changes and the electromagnetic force changes, the rate of change of the electromagnetic force at that time k _fn and the diaphragm Since the rate of change kε of the deflection force of the biasing element relative to the displacement of the valve body (plunger) is approximately equal, changes in electromagnetic force are absorbed and the governor setting force can be kept constant.
Furthermore, since changes in electromagnetic force do not affect the governor characteristics, the magnetic efficiency of the drive section is increased and control can be performed with a small magnetomotive force. Therefore, the drive unit can be made smaller.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross-sectional structural diagram of a pressure proportional control valve according to the present invention. 19 is a governor section and fluid inlet 2
A valve body 23 with a valve seat 22 provided between the valve seat 22 and the fluid outlet 21, and a membrane plate 25 with a diaphragm 24 provided above and below that operates in response to pressure on the fluid inlet 20 side.
a and 25b, a valve body 28 fixedly attached by a pin 26 and a push nut 27, and a seal made of an elastic material that is fitted into the valve body 28 and held by a ring holder 29 and contacts the valve seat 22 to open the valve. It has a biasing element 31 and a base cap 32 that bias the ring 30 and the valve body 28 in the valve closing direction.

33 is a drive unit, which includes a coil 34 and a coil 34
The yoke 35 and the yoke plate 3 are provided to surround the
6, and a plunger 39 that is movable up and down in a sliding pipe 38 that penetrates through the center of the coil 34.
When energized, an electromagnetic force is generated, and the plunger 39 is displaced downward to displace the valve body 28 and control the pressure (flow rate) of the fluid outlet 21.

In the above configuration, when the current is not energized, the biasing element 31
As a result, the valve body 28 receives a valve closing force, and the seal ring 30 is pressed against the valve seat 22 to cut off fluid flow. Next, when the coil 34 is energized, electromagnetic force acts on the plunger 39 to displace the valve body 28 downward, and the fluid outlet 21
side pressure is controlled and also has a well-known governor function. In other words, it is a multifunctional pressure control valve that has the three functions necessary for this type of pressure control valve: proportional control, fluid cutoff, and governor.

Figure 2 shows the amount of displacement X _v of the valve body 28 and the coil 34.
Relationship between electromagnetic force F _n when a predetermined amount of current is applied to diaphragm 24 and valve body 28 of biasing element 31
This figure shows the relationship between the total deflection force F _k and the displacement X _v of . Here, in this type of plunger type drive unit 33, the resultant force of the solenoid suction force that pulls in the plunger 39 by the coil 34 and the suction force that acts between the upper surface 39a of the plunger 39 and the yoke upper surface 35b, and between the lower surface 39b of the plunger 39 and the yoke plate 36. acts as an electromagnetic force F _n that displaces the plunger 39 downward. The solenoid suction force is greatest when the center of the plunger 39 is located at the center in the height direction of the coil 34, and the latter suction force increases as the air gap becomes smaller in proportion to the square of the air gap. As a result, when the plunger 39 is displaced while the magnetomotive force, that is, the amount of current applied to the coil 34 is kept constant, the electromagnetic force F _n has an upward-sloping characteristic as shown in FIG. In this embodiment, the valve body 28 is fully opened from the closing point.
The ratio of the amount of change △F _{n in} electromagnetic force F _n to _the amount _of displacement
The ratio kε=ΔF _k /X of the amount of change ΔF _k is set approximately equal. Therefore, as shown in Fig. 3, the governor setting force Fg for keeping the pressure on the fluid outlet 21 side constant, that is, the difference between the electromagnetic force Fm and the deflection force Fk, remains approximately the same even if the valve body displacement _Xv changes. It can be made constant. As a result, ideal governor characteristics without fluctuations in the secondary pressure _P2 can be obtained, as shown in the characteristics of FIG. 8C.

As described above, according to this embodiment, the valve body displacement X _v
The rate of change of the electromagnetic force F _n with respect to the displacement k _fn and the deflection force
Good governor characteristics can be obtained by simply making the rate of change k of _Fk approximately the same (specifically, adjusting the spring constant of the biasing element 31). In general, in this type of plunger type electromagnetic drive unit, the higher the magnetic efficiency in the magnetic circuit, the more the plunger 39
Although the change in the electromagnetic force Fm with respect to the displacement becomes large, in this embodiment, the change in the electromagnetic force _Fn is canceled by using the spring constant of the biasing element 31, so that the drive section 33 having a large change in electromagnetic force can be used. This means that the upper surface 39a of the plunger 39 and the yoke 35
Between the upper surfaces 35a and the lower surface 39 of the plunger 39
The air gap between the yoke 35 and the yoke plate 36 can be reduced, and the magnetic resistance of the magnetic circuit formed by the yoke 35, the yoke plate 36, and the plunger 39 can be reduced. Therefore, the drive unit 33 can be made smaller and lower in cost. Further, since a seal ring 30 made of an elastic body is provided between the valve seat 22 and the valve body 28 for closing, it is possible to provide a multifunctional pressure proportional control valve having proportional control, fluid cutoff, and governor functions. In particular, when adding a fluid cutoff function, it is necessary to increase the setting force of the biasing element 31. However, according to this embodiment, even when this type of fluid cutoff function is provided, the spring constant of the biasing element 31 can be increased. As a result, good governor characteristics can be obtained, and the biasing element 3
1 can be made compact.

When controlling fuel gas, the calorific value differs depending on the gas type, and the control secondary pressure P ₂ and valve opening X _v
Since the values are different, the control current to the coil 34 and the rate of change k _fn of F _n will inevitably be different, but the spring constant of the biasing element 31 may be changed depending on each gas type. In addition, if a slight range of change in governor characteristics is allowed, the rate of change k _fn and deflection when controlling a gas type where the control secondary pressure P ₂ is an intermediate value, for example, a natural gas group such as 13A, If the rate of change of force k〓 is approximately the same, fuel gas can be used in common.

Effects of the Invention As detailed above, according to the present invention, the following effects can be obtained.

(1) Using a plunger type drive unit and the rate of change of electromagnetic force k _fn with respect to the amount of displacement of the valve body X _v
The governor characteristics can be improved by simply making the rate of change k of the deflection force of the diaphragm and the biasing element approximately equal (specifically, adjusting the spring constant of the biasing element). This is particularly suitable when performing highly accurate flow rate control such as air-fuel ratio control.

(2) Since changes in electromagnetic force F _n are absorbed by the biasing element, a drive unit with large changes in electromagnetic force can be used. Therefore, the magnetic efficiency of the electromagnetic drive section can be increased, and the drive section can be made smaller and lower in cost.

(3) Even when the valve closing force is increased, such as when a closing function is added, the governor characteristics are not deteriorated.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a pressure proportional control valve showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing changes in the valve body displacement amount and electromagnetic force, and Fig. 3 is a characteristic diagram showing the valve body displacement amount and governor. A characteristic diagram showing the relationship between setting forces. Fig. 4 is a cross-sectional view of a pressure proportional control valve showing a conventional example. Fig. 5 is a cross-sectional view of a pressure proportional control valve showing another conventional example. Fig. 6 is a cross-sectional view of a pressure proportional control valve showing another conventional example. FIG. 7 is a diagram showing the relationship between the displacement amount of the valve body and the electromagnetic force, FIG. 7 is a diagram showing the relationship between the displacement amount of the valve body and the governor setting force, and FIG. 8 is a diagram showing the governor characteristics. 19...Governor part, 20...Fluid inlet, 21...
...fluid outlet, 22 ... valve seat, 24 ... diaphragm, 28 ... valve body, 31 ... biasing element, 33 ...
Drive unit, 34... Coil, 37... Fixed magnetic body,
39... Plungiya.

Claims (1)

[Claims] 1. A valve seat provided between a fluid inlet and a fluid outlet, a valve body provided opposite to the valve seat, and a diaphragm that is integrally provided with the valve body and operates in response to fluid pressure.
a governor section including a biasing element that biases the valve body in a valve closing direction; a coil; and a fixed magnetic body;
and a plunger that operates the valve body by the electromagnetic force generated by energizing the coil, and the valve body has a change rate k _fn of the electromagnetic force with respect to the displacement of the plunger, the diaphragm, and the valve biasing element. A pressure proportional control valve that approximately matches the rate of change k of deflection force with respect to body displacement so that the governor setting force remains constant.