JPS5828080A - Proportional control valve for gas - Google Patents

Abstract

PURPOSE:To reduce the magnetic hysteresis and stabilize the pressure characteristic of an electromagnetic valve by allowing the stroke of the plunger of the valve to correspond to the species of gas so that a necessary opening is maintained, and installing the valve body stopper which moves freely on the bottom cover of the valve thus restricting the max. transfer distance of the valve. CONSTITUTION:The pushing rod 17 at the lower edge of a plunger 12 faces the top edge of a valve body 5 through the sliding pin 9 supported onto a bearing 8. Under the valve body 5, a valve body stopper 24 is screwed with a bottom cover 26 with free advancing and retreating movement, so the stroke of the plunger 2 can be restricted, and a proper opening degree of the valve can be maintained according to the species of gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a gas control valve that proportionally controls the pressure of gas supplied to a burner of a gas combustion device using an electric signal.
This invention relates to an electric drive unit that has a magnetic material in its movable body.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas control valve having excellent gas pressure control characteristics by completely resolving the drawbacks in gas pressure control characteristics caused by magnetic hysteresis of the magnetic material of the electric drive unit.

A conventional example will be explained using FIG. The body 1 has a fluid population 2, an outlet 3. A valve seat 4 is fully formed, and a valve body 6 is fixed to a diaphragm 6 opposite to the valve seat 4, forming a gas governor section.The central upper part of the valve body 6 passes through the diaphragm 6 and is press-fitted into a damper plate 7. A damper chamber 10 is formed by contacting a sliding pin 9 supported by a bearing 8 .

11 is a damper JL, which communicates with the atmosphere.

Plunger 12, coil 13 and yoke 1 as movable bodies
4.15, configure the entire electromagnetic force generation section.

The plunger 12 is made of a magnetic material and is supported coaxially with the coil 13 by two leaf springs 16 at the upper and lower parts.
Moves up and down without sliding. Reference numeral 17 denotes a push rod made of a non-magnetic material, the lower end of which abuts against the upper center of the valve body 6. 18 and 19 are the upper and lower leaf spring mounting bases, respectively. 20 is a coil spring that cancels out the weight of the granger 12, the valve body 6, etc. 2
1 is a seal pipe passing through the center of the coil 13; 22
is the upper pig. 23 is the bottom pig.

- In the configuration described above, when a current is passed through the coil 13, an electromagnetic force is generated, which acts to push the plunger 12k downward. This electromagnetic force changes depending on the magnitude of the current. This electromagnetic force acts so that the push rod 17 pushes the valve body 5 through the sliding pin 9. According to the well-known governor principle, the pressure P2 of the fluid flowing out from the outlet 3 is determined by the force acting on the valve body 6.

That is, the value of the current flowing through the coil 13 and the pressure P2 can be arbitrarily changed within a certain range. Damper chamber 10
has a damper effect that completely suppresses the rapid movement of the valve, and is effective in preventing valve vibration. The magnitude of the damper action can be set depending on the magnitude of the damper J111. Therefore, it is designed to satisfy the effect of vibration prevention and to have virtually no problem in response of the outlet pressure to changes in the coil current.

The drawback of the conventional example in such a configuration is that the plunger 1
2. Due to the magnetic hysteresis caused by the magnetic monthly rate and the magnetic circuit, when the supply gas pressure P1 decreases or due to temporary fluctuations, the pressure decreases, even though the same current is being generated. The problem is that the outlet pressure P2 changes. This is electromagnetic! ! , IX The electromagnetic force of moving parts (the relationship between plunger displacement and electromagnetic force in This is because there is a so-called magnetic hysteresis phenomenon in which the forces are different.

Figure 4 shows how the electromagnetic force changes at different currents of 5, 9, and 3. coil? 1" The magnitude of the current is
(5) The larger the current, the larger the magnetic hysteresis. Therefore, in the case of LPG with the largest set gravity P2, a large coil current is naturally required, and the pressure at this time! The characteristics are as shown in FIG. 5 (a). The horizontal axis in FIG. 6 is the supply gas output P1, and the vertical axis is the outlet pressure P2. That is, when P2 is set at point A in FIG. 5, the supply gas pressure P1 is p2'J:! When ll becomes smaller and Pl returns to the re-string, the displacement of the plunger moves as shown in Figure 4 (A).This means that Pl is
When the outlet pressure becomes smaller than P2, the electromagnetic force and P2 increase by 4[
51. to the valve body 6. - Due to the imbalance of the acting forces and the displacement of the plunger up to its maximum travel distance LM.

As shown below, in conventional gas control valves.

The maximum travel distance LM of the plunger is selected to the value required for the gas type with the largest valve opening of the gas control valve, such as city gas, so a smaller valve opening may be required for other gas types, such as LPG. In this case, the magnetic hysteresis deteriorates when the supply force P1 decreases, so there is a drawback that the outlet pressure P2 is unstable.

The present invention eliminates all of the above-mentioned drawbacks of the prior art by providing means for adjusting the stroke of the plunger to the required valve opening degree in accordance with the type of gas.

An embodiment of the present invention is shown in FIG. 1 below. In FIG. 1, the same members as those in FIG. 6, which shows a conventional gas control valve, are designated by the same reference numerals, and their explanations will be omitted. 24 is the maximum movement path Ni1. of the plunger 12 interlocking with the valve body 5. L M'(i:
, is a regulating valve stop. The valve body stop 24 has a threaded portion 2.
5, and the maximum movement b"1 axis 1 [LM
can be set in multiple stages 91: sea urchin, bottom cover 26 also has threaded part 2
6 will be provided. 27 is an O-ring for sealing.

With the above configuration, the optimum maximum moving distance of the plunger can be set depending on the type of gas, so that even if the supply pressure P1 decreases, the displacement of the plunger 12 is kept to the minimum necessary level, so that the magnetic hysteresis is also reduced. Therefore, pressure characteristics as shown in FIG. 2 are obtained, and the outlet pressure P2 is stabilized.

As described below, according to the present invention, the instability of pressure characteristics caused by magnetic hysteresis can be eliminated by a simple configuration even in a gas control valve using electric drive that has good magnetic hysteresis, and a gas control valve with stable characteristics can be achieved. can be provided.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a gas control valve that is an embodiment of the present invention, and Fig. 2 is a pressure characteristic diagram of an embodiment of the present invention.
FIG. 3 is a front sectional view of a conventional gas control valve, FIG. 4 is a displacement-electromagnetic force characteristic diagram of the same gas control valve, and FIG. 6 is a pressure characteristic diagram of the same gas control valve. 4... Valve seat, 5... Valve body, 6...
・Diaphragm, 12... Plunger, 13.
River: Electromagnetic coil, 24: Valve body city. Name of agent: Patent attorney Toshio Nakao (1st person)
Ward Figure 2 β Figure 3 23 π Figure 4 Figure 5-〉Pl

Claims (2)

[Claims] (1) An electromagnetic drive unit having a valve body and a valve seat fully facing each other, a gas governor part having a diaphragm fixed to the valve body, an electromagnetic coil, and a movable body that proportionally controls the valve body by the energizing current of the electromagnetic coil. Thus, a gas proportional control valve is provided in which the maximum travel distance of the movable body interlocked with the valve body can be set arbitrarily. (2) The gas proportional control valve according to claim 1, further comprising a valve body stop having an entire threaded portion as a means for arbitrarily setting the maximum travel distance of the movable body.