JPS5819829A - pressure switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure switch that detects pressure and turns on or cuts off current, which turns on electricity between two different set pressures and cuts off current at other pressures. Regarding.

Conventional pressure switches either have the characteristic (2) in Figure 1, which cuts off the current when the pressure is higher than the set pressure and conducts the current when the pressure is lower than the set pressure, or have the opposite characteristic (g) in Figure 1. Common.

Therefore, as shown in the characteristic of Q in Figure 1, if there are two different set pressures P* - Pt (However, if the current is passed between PI - < PI > and the current is cut off between 21 and above and below P1,
It was necessary to use both pressure switches with the characteristics shown in Figure 1 and (2) in series. For this reason, the number of parts increases, and it is necessary to connect two pressure switches, which is troublesome.

Therefore, an object of the present invention is to provide a pressure switch that has the function of passing current between two different set pressures and cutting off current at other pressures.

In order to achieve such an object, the present invention operates two movable contacts set by respective springs via a pressure-sensing diaphragm in accordance with the detected pressure, and operates in combination with a fixed contact. By stopping, making contact or non-contact between the contacts, the current is passed between two set pressures, and the current is cut off at other pressures.

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

The characteristics of the pressure switch of the present invention are as shown in FIG. 1. Current is cut off at a lower set pressure P or lower and at a higher set pressure 22 or higher, and current is passed between P and -yp.

A cross-sectional view of the principle structure showing one embodiment of the present invention is shown in FIG.
Cross-sectional views of specific examples are shown in FIGS. 3 to 6.

The pressure switch main body consists of a cap-shaped case 1 and a funnel-shaped lid 2 attached to the opening side of the case 1, and a diaphragm 3 is fixed between the lid 2 and the case 1. This pressure switch body is connected to a joint 4 of a container or the like containing a pressure-sensing object via a sealing object such as an O-ring 5, and the pressure-sensing object enters an internal chamber 6 from the tip of the lid body 2. It sinks into contact with the outer surface of the diaphragm 3 which acts elastically.

A retainer 7 is disposed on the inner surface of the diaphragm 3 and contacts the movable portion of the diaphragm 3. Inside the retainer 7, a disk-shaped first movable contact 8, a guide 9, and a spring 1 are arranged in order.
0 is placed. As a result, the first movable contact 8 is pressed against the diaphragm 3 via the retainer 7 by the restoring force of the spring 10 via the guide 9.

On the other hand, a second movable contact 1 surrounding the guide 9 in a non-contact manner
1 is provided. The second movable contact 11 has a split structure in which it is divided into left and right halves at the center, as shown in an example in FIG. This second movable contact 11 is pressed toward the diaphragm 3 by a spring A-g 13 via a guide 12. In addition, a pair of fixed contacts 1 are arranged opposite to the inner wall of the case 1.
4 are arranged. The outer end 15 of the fixed contact 14 protrudes from the case 1 to constitute a terminal electrode, and the inner end is bent toward the center to constitute a contact terminal 16. Therefore, the second movable contact 11 reciprocates in the axial direction of the cap-shaped case 1, contacts the first movable contact 8 at the inner edge, and contacts the fixed contact 1 at the outer edge.
4.

The movable contacts 8 and 11 and the fixed contact 14 are made of conductive material, and the second movable contact 11 has a gap between the fixed contacts 14 in the reciprocating range, as shown in FIG. There is no electrical continuity in the middle. On the other hand, case 1, guide 9. i2, the retainer 7 is made of an insulating material. In addition, in FIG. 6, the two rotating contacts 8.degree. 11 and the fixed contact 14 are illustrated with hatching for easier understanding.

Next, the operation of the pressure switch according to this embodiment will be explained.

First, when the pressure in the chamber 6 is lower than P, the force of the spring 10 is greater than the force exerted on the diaphragm 3 by the pressure in the chamber 6, and as shown in FIG. A gap is created between the movable contacts 11, and the left and right fixed contacts 14 are electrically opened. In this case, the second movable contact 11 contacts and is fixed to the fixed contact 14 by the action of the spring 13.

If the pressure in the chamber 6 drops too much, the guide 9 will come into contact with the guide 12 or the second movable contact 11, the stroke will be restricted, and the excessive force of the spring 10 will no longer act on the diaphragm 3.

When the pressure in chamber 6 is between P and P, as shown in FIG.
Due to the pressure in the chamber 6, the force applied to the diaphragm 3 becomes greater than the force of the spring 10, and the first movable contact 8 and the second movable contact 11 come into contact. Since the force of the spring 13 applied to the second movable contact 11 is greater than the force from the first movable contact 8, the second movable contact 11 remains in contact with the fixed contact 14.

As a result, the second movable contact 11 is connected between the left and right solid bag contacts 14.
, are electrically connected via the first movable contact 8.

When the pressure in the chamber 6 is higher than P, as shown in FIG.
The second movable contact 11 is pushed up while in contact with the second movable contact 11, and the second
A gap is created between the movable contact 11 and the fixed contact 14, and the left and right fixed contacts 14 are electrically opened. Note that if the pressure in the chamber 6 rises too much, the retainer 7 will come into contact with the fixed contact 14, and the stroke will be restricted.

As a result of the above, according to one embodiment of the present invention, it is possible to obtain the characteristic of energizing operation in a desired pressure range with one switch, as shown in FIG. 10.

As an example of the effective use of the switch of the present invention, a case of a refrigeration cycle shown in FIG. 7 will be described below.

In a general refrigeration cycle, refrigerant compressed by a compressor 17 is condensed in a condenser 18, passes through a liquid receiver 19, and then passes through an expansion valve 2.
The air is expanded at zero, cooled by the heat of evaporation in the evaporator 21, and returned to the compressor 17.

Generally, for safety reasons, there is a safety valve 22 on the high-pressure refrigerant side of the expansion valve 20 from the condenser 18 that releases the refrigerant into the atmosphere when the pressure exceeds a certain level, or a fusible plug that releases the refrigerant into the atmosphere when the temperature exceeds a certain level. Alternatively, a high-pressure cut switch (not shown) is installed that turns off the drive power to the compressor when the pressure exceeds a certain level.

On the other hand, recently, many cycles are also equipped with a low-pressure cut switch 23 that senses a drop in pressure when the amount of refrigerant decreases due to a leak or the like and turns off the drive power to the compressor.

By installing the switch of the present invention from the condenser 18 to the high-pressure refrigerant side of the expansion valve 20, the above two functions can be performed, and the number of parts and installation work can be reduced. Note that the present invention is not limited to the above embodiments. That is,
The current is cut off between pressure P and P2, and PI
Electricity may be applied in a lower pressure range or a pressure range higher than P2.

Furthermore, the number of movable contacts may be further increased to provide a large number of set pressures, and switching between energization and disconnection may be performed under each set pressure.

As described in detail above, according to the present invention, it is possible to conduct current between two different set pressures with one switch, and to cut off current at other pressures.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the pressure switch mode, Fig. 2 is a sectional view showing the principle and construction of the pressure switch of the present invention, and Figs.
FIG. 5 is a sectional view showing various operating states in one embodiment, FIG. 6 is a plan view, and FIG. 7 is a schematic diagram showing an example of application. 1... Case, 3... Diaphragm, 6... Chamber,
7... Retainer, 8... First movable contact, 9.12.
...Guide, 10.13...Spring, 11...
2nd movable contact, 1st Z Saiji, intellectual pressure J$q Figure 5 Figure 6 Mouth A-I'/

Claims (1)

[Claims] 1. In a pressure switch that operates a movable contact that is elastically sensitive to pressure and makes contact or non-contact with a fixed contact at a set pressure to turn on or cut off current, 1. A pressure switch characterized in that a plurality of movable contacts with different values are provided, and energization or interruption is performed at different set pressures. 2. Has two movable contacts with different set pressures, and has two different
2. The pressure switch according to claim 1, wherein current is supplied between two set pressures, and the current is cut off when the pressure is higher than the higher set pressure or lower than the lower set pressure.