JPS6254223B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure switch that detects the pressure of refrigerant in a refrigeration cycle and disconnects electrical circuits.
More particularly, it relates to a pressure switch that responds to three different pressure conditions.

The conventional pressure switch shown in Japanese Patent Publication No. 47-15666 cuts off the current when the pressure exceeds the set pressure.
It is common to have the characteristic A in FIG. 1, which allows the current to flow below the set pressure, or the characteristic shown in FIG. 1B, which is the opposite.

Therefore, as shown in the characteristic C in Figure 1, when the current is passed between two different set pressures P ₁ and P ₂ (however, P ₁ < P ₂ ), and the current is cut off at P ₂ or higher and P ₁ or lower. In this case, it was necessary to use both pressure switches having characteristics A and B in FIG. 1 in series. For this reason, the number of parts increases and the work of connecting two pressure switches is required, which is troublesome.

Therefore, an object of the present invention is to provide a pressure switch which 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 disconnects the movable contact from the fixed contact in response to the displacement of the diaphragm when the pressure acting on the diaphragm is lower than a first set pressure, and the pressure acting on the diaphragm is lower than or equal to a first set pressure. The movable contact is brought into contact with the fixed contact in accordance with the displacement of the diaphragm when the pressure is higher than the first set pressure and lower than the second set pressure higher than the first set pressure, and the pressure acting on the diaphragm is Means is provided for disconnecting the movable contact from the fixed contact in response to displacement of the diaphragm when the pressure exceeds a second set pressure.

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. 1C, and the current is cut off at a lower set pressure _P1 or less and at a higher set pressure _P2 or higher, and the current is passed between _P1 and _P2 .

A sectional view of the principle structure showing one embodiment of the present invention is shown in the second
In the figure, sectional views of one specific example are shown in FIGS. 3 to 6.

The pressure switch body consists of a cap-shaped case 1,
It consists of 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 through 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. , in 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 10 are arranged in this order. 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 11 is provided that surrounds the guide 9 in a non-contact manner. This 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 13 via a guide 12. Further, a pair of fixed contacts 14 are disposed on the inner wall of the case 1 in opposition to each other. 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 14 at the outer edge.

The movable contacts 8 and 11 and the fixed contact 14 are made of conductive material, and the second movable contact 11
As shown in Figure 6, in the reciprocating range, the fixed contact 1
There is a gap between the four parts, so that there is no electrical conduction during movement. On the other hand, the case 1, guides 9 and 12, and retainer 7 are made of insulating material. In addition, in FIG. 6, both movable contacts 8,
11 and fixed contact 14 are explained with hatching for easy 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 _P1 , 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 contacts 11, and the left and right fixed contacts 14 are electrically opened. In this case, the second movable contact 11 is the spring 13
It contacts and is fixed to the fixed contact 14 by the action of.
If the pressure in chamber 6 drops too much, guide 9 will switch to guide 1.
2 or the second movable contact 11, the stroke is restricted and the excessive spring 1 is applied to the diaphragm 3.
Zero force no longer acts.

When the pressure in the chamber 6 is between P ₁ and P ₂ , the force applied to the diaphragm 3 due to the pressure in the chamber 6 becomes greater than the force of the spring 10, as shown in FIG. The movable contact 11 makes 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, electrical continuity is established between the left and right fixed contacts 14 via the second movable contact 11 and the first movable contact 8.

When the pressure in the chamber 6 is higher than _P2 , as shown in FIG. The two movable contacts 11 are pushed up while in contact, and a gap is created between the second movable contacts 11 and the fixed contacts 14, causing the left and right fixed contacts 14 to
It is electrically opened in between. Note that if the pressure in the chamber 6 rises too much, the retainer 7 will come into contact with the fixed contact 14,
Stroke is regulated.

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. 1C.

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, the refrigerant compressed by the compressor 17 is condensed by the condenser 18, and the refrigerant is condensed by the liquid receiver 19.
The air is expanded by an expansion valve 20, cooled by the heat of evaporation in an evaporator 21, and returned to the compressor 17.

Generally, for safety reasons, the expansion valve 20 is removed from the condenser 18.
A safety valve 22 that releases the refrigerant to the atmosphere when the pressure exceeds a certain level, a fusible plug (not shown) that releases the refrigerant to the atmosphere when the temperature exceeds a certain temperature, or a compressor that releases the refrigerant to the atmosphere when the pressure exceeds a certain level. A high-voltage cutoff switch (not shown) is installed to cut off the driving power.

On the other hand, recently, many cycles are also equipped with a low-pressure cutoff 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.

The switch of the present invention is connected from the condenser 18 to the expansion valve 20.
By installing the refrigerant on the high-pressure refrigerant side, 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 may be cut off between pressures P ₁ and P ₂ and may be turned on in a pressure range lower than P ₁ or higher than P ₂ .

Further, the number of movable contacts may be further increased to provide a large number of set pressures, and energization and cutoff may be switched at each set pressure.

As described in detail above, according to the present invention, one switch can energize and switch between two different set pressures.
At other pressures, the effect is that the current can be interrupted.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the pressure switch mode, FIG. 2 is a sectional view showing the principle structure of the pressure switch of the present invention, FIGS. 3 to 5 are sectional views showing each operating state in one embodiment, and FIG. The figure is also a plan explanatory diagram,
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, 1
1... Second movable contact, 14... Fixed contact.

Claims (1)

[Claims] 1. A diaphragm, a fixed contact disposed on one side of the diaphragm, disposed between the fixed contact and the diaphragm, displaced together with the diaphragm, and brought into superimposed contact with the fixed contact due to this displacement. The first movable contact is located at a position where there is no contact, and the first movable contact is disposed on the opposite side of the first movable contact of the fixed contact and is displaced in the opposite direction to the displacement of the first movable contact. a second movable contact located at a position where the movable contacts overlap and contact each other; a first elastic member provided to separate the first movable contact from the fixed contact against the displacement; A pressure switch comprising: a second elastic member provided to bring the second movable contact into contact with the fixed contact.