JPH0121191Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The invention is designed to stop the compressor when the amount of refrigerant circulating in the refrigeration cycle due to the drive of the compressor decreases to a predetermined value or less. According to
This invention relates to a compressor protection device that solves problems in refrigeration cycles.

(Prior Art) For example, a refrigeration cycle is constructed by sequentially connecting a compressor 1, a condenser 2, and an evaporator 3 through a conduit 4, as shown in FIG. A liquid tank 5 and an expansion valve 6 are arranged.

The high-temperature, high-pressure refrigerant gas discharged from the compressor 1 is sent to the condenser 2, where it is cooled and liquefied to become a high-temperature, high-pressure refrigerant liquid. The high-temperature, high-pressure refrigerant liquid passes through the condenser 2 and is adjusted in the liquid tank 5, and then undergoes a rapid throttling action at the expansion valve 6 to undergo adiabatic expansion and becomes a low-temperature, low-pressure atomized refrigerant. The refrigerant liquid, which has been turned into a spray at low temperature and low pressure by the expansion valve 6, is sent to the evaporator 3, where it is absorbed by heat from the passing air and vaporized, becoming a low-pressure refrigerant gas at room temperature, and returned to the compressor 1.

On the other hand, in the above-mentioned refrigeration cycle, a temperature switch for detecting a rise in refrigerant temperature is installed on the discharge side of the compressor, and a pressure switch for detecting a drop in refrigerant pressure is installed in the liquid tank. When a drop is detected, a signal is sent to the control device to stop the compressor from operating and protect the compressor.

(Problem that the invention attempts to solve) However, with the above type of compressor protection device,
It requires two switches, a temperature switch and a pressure switch, and has the disadvantage that not only does it require a large space to install these switches, but also a lot of time is required for installation, wiring, etc., resulting in poor workability.

The present invention was devised in view of the above points, and the actuating piece provided inside the main body of the device is brought into contact with and separated from the terminal by a diaphragm and bimetal, thereby simplifying workability and reducing costs. The purpose of the present invention is to provide a compressor protection device that provides improved protection.

[Structure of the idea]

(Means for Solving the Problems) The present invention to achieve the above object is to attach a diaphragm to a device body provided with a fixed contact and an actuating piece having a movable contact that contacts the fixed contact. A lid body is attached, and a refrigerant chamber is formed between the lid body and the diaphragm into which the refrigerant in the refrigeration cycle flows through a hole bored in the lid body, and a refrigerant chamber is formed between the diaphragm and the device main body. a spring member forming a spring chamber therebetween, applying elastic force to the actuating piece so that the movable contact moves away from the fixed contact, and applying elastic force to the diaphragm toward the refrigerant chamber; Attached to the main body of the device, it applies elastic force to the diaphragm toward the spring chamber against the elastic force of the spring member, and releases the elastic force to the diaphragm depending on the temperature in the refrigerant chamber. This compressor protection device is characterized in that a bimetal that deforms in the direction of refrigerant is installed in the refrigerant chamber, and the compressor is stopped by detecting an increase in the temperature of the refrigerant or a decrease in the pressure of the refrigerant.

(Function) When the temperature of the refrigerant in the refrigerant chamber becomes higher than a predetermined value, the bimetal releases the elastic force on the diaphragm, and the diaphragm deforms toward the refrigerant chamber. This causes the movable contact to separate from the fixed contact and the compressor to stop. Furthermore, when the pressure of the refrigerant in the refrigerant chamber drops to a predetermined value or more, the elastic force of the spring member overcomes the elastic force of the bimetal in the opposite direction and the pressure in the evaporation chamber, causing the diaphragm to deform toward the refrigerant chamber. do. This causes the movable contact to separate from the fixed contact and the compressor to stop. In cases other than the above, the movable contact and the fixed contact are in contact with each other, and the compressor is in a state where it can rotate.

(Example) An example of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing the position where the compressor protection device 10 of the present invention is installed.
is attached to the top plate portion 5a of the liquid tank 5 of the refrigeration cycle.

As shown in FIG. 3, this compressor protection device 10 includes a stepped cylindrical device main body 11, and a roughly stepped cylindrical lid that is attached to the device main body 11 and has a diaphragm 14 mounted between the device main body 11. It has a body 13. This diaphragm 14
The first clamping member 1 is two annular clamping members.
4a and the second holding member 14b, and placed on the stepped portion of the lid 13. Second holding member 14
Reference numeral b designates a clamping member mounted above, and since it also serves as a stopper for regulating the moving distance of the support body 20, which will be described later, it has an annular shape that is wider than the first clamping member 14a. This lid body 13 and the device body 1
1 and 2, a space 12 is formed inside these. This space 12 is divided into a refrigerant chamber 21 and a spring chamber 15, which will be described later, by a diaphragm 14 stretched between the device main body 11 and the lid 13. That is, a refrigerant chamber 21 is formed between the diaphragm 14 and the lid 13 into which the refrigerant in the refrigeration cycle flows through the hole 23 formed in the lid 13. A spring chamber 15 is formed between the diaphragm 14 and the coil spring 19 to which the diaphragm 14 applies elastic force.

As shown in the figure, an actuation piece 16 is rotatably mounted inside the device main body 11, a terminal 17a of a lead wire is connected to this actuation piece 16, and a movable contact is provided at the tip of the actuation piece 16. 16a is provided. This movable contact 16a can freely come into contact with and separate from a fixed contact 17 built into the device main body 11, and this fixed contact 17 is connected to a terminal 17b of a lead wire. Therefore, these contacts 16
When a and 17 are in contact, the compressor is activated by a circuit (not shown), and when they are separated, the compressor is stopped.

An adjustment screw 24 is screwed into a recess 18 formed in the device main body 11, and a col spring 19 as a spring member is provided between the adjustment screw 24 and the receiver 25. Between the receiver 25 and the diaphragm 14 is a mounting bracket 26 that is assembled to the actuating piece 16 and has a dish-shaped disk fixed to its lower end;
The support body 20 is located in contact with the mounting bracket 26, and the coil spring 19 applies an elastic force to the actuating piece 16 in the direction in which the movable contact 16a moves away from the fixed contact 17. Mounting bracket 2
An elastic force is applied to the diaphragm 14 in a direction in which the diaphragm 14 moves toward the refrigerant chamber 21 via the refrigerant chamber 6 and the support body 20 . The set value of this resilient force can be adjusted by rotating the adjustment screw 24.

A known bimetal 22 is installed inside the refrigerant chamber 21 . This bimetal 22 has a curved rectangular shape as shown in FIG. The diaphragm 14 is bent through a spacer 27 that is curved convexly toward
and become one. This spacer 27 has elasticity that can follow the deformation of the bimetal. In the state shown in FIG. 3, the force applied to the diaphragm 14 by the elastic force of the bimetal 22 and the pressure of the refrigerant in the refrigerant chamber 21 is applied from the coil spring 19 to the receiver 25, the mounting bracket 16, and the support. The force applied to the diaphragm 14 via the body 20 is balanced, and the diaphragm 14 is in a neutral state as shown in FIG. ing.

Next, the operating state of the illustrated compressor protection device will be explained.

In the normal state, that is, when the pressure of the refrigerant in the refrigeration cycle is above a predetermined value and the temperature of the refrigerant is below the predetermined temperature, the coil spring 19 springs as shown in FIG. Since the pressure of the refrigerant in the refrigerant chamber 21 and the elastic force of the bimetal 22 are applied to the diaphragm 14 against the force, the diaphragm 14 is in a neutral position as shown in the figure.
The movable contact 16a is in contact with the fixed contact 17, and both terminals 17a and 17b of the lead wire are in a connected state. Thereby, the compressor 1 is maintained in an operable state.

Next, if the temperature of the refrigerant abnormally rises due to a decrease in the amount of refrigerant, that is, if it rises to a temperature higher than the set temperature, as shown in FIG. Depending on the temperature of the refrigerant, the bimetal 22 is thermally deformed so that its both ends 22a are on the diaphragm 14 side and the center is on the lid body 13 side, as shown in the figure. As a result, this bimetal 22 causes the diaphragm 14 to
Since the elastic force applied to the refrigerant chamber 2 is released, the refrigerant chamber 2
The force of pressing the diaphragm 14 toward the refrigerant chamber 21 by the coil spring 19 is relatively larger than that of pressing the diaphragm 14 toward the spring chamber 15 by the pressure of the refrigerant in the coil spring 19.
As a result, the support body 20 moves the diaphragm 14 toward the refrigerant chamber 21 side, and the actuating piece 16 moves so that the movable contact 16a separates from the fixed contact 17. As a result, both terminals 17a and 17b of the lead wire are separated from each other, and the compressor is stopped. Note that the maximum moving distance of the support body 20 toward the refrigerant chamber 21 is as follows:
The outer peripheral part 20a of the support body 20 is connected to the second holding member 1.
It is regulated by coming into contact with 4b.

Furthermore, when the amount of refrigerant decreases, the pressure of the refrigerant also decreases, and if the refrigerant pressure decreases abnormally, that is, if the refrigerant pressure decreases below a predetermined value, as shown in FIG. Since the pressure of the refrigerant in the refrigerant chamber 21 becomes low, this pressure drop causes the total pressure of the bimetal 22 that presses the diaphragm 14 upwards and the refrigerant pressure to become the pressure that presses the diaphragm downwards due to the coil spring 19. The temperature decreases further, and the diaphragm 14 deforms toward the refrigerant chamber 21 side. As a result, both terminals 17 of the lead wire
a and 17b are separated and the compressor stops. Note that the spring chamber 15 is connected to both terminals 17a of the lead wire.
The diaphragm 14 is in communication with the outside through the parts to which the diaphragm 14 and 17b are attached, and the diaphragm 14 can be easily deformed, that is, can move.

By the way, when the amount of refrigerant in the refrigeration cycle decreases below a predetermined value, a phenomenon generally occurs in which the temperature of the refrigerant increases and the pressure of the refrigerant decreases. If the refrigeration cycle is started with the amount of refrigerant below a predetermined value, there may be a time difference between when the refrigerant pressure drops below the predetermined value and when the temperature rises above the predetermined value in the cycle, or Depending on the amount of refrigerant, it may be difficult for one of the predetermined values of temperature and pressure to appear.

With this invention, if either the temperature or pressure is detected as an abnormal value, the operation of the refrigeration cycle can be stopped, so even if the amount of refrigerant decreases, the temperature in the refrigeration cycle will remain at the predetermined value. Even if there is a difference between the time it takes for the pressure to reach the above level and the time it takes for the pressure to drop to the predetermined value or less, or even if one of them is not noticeable, the compressor can be reliably stopped. Further, even if one of the temperature sensing portion and the pressure sensing portion fails, the compressor protection device of the present invention will operate reliably and the safety of the compressor can be more reliably achieved.

[Effect of idea]

As described above, according to the present invention, when the refrigerant in the refrigeration cycle decreases to a predetermined value or less,
By detecting the abnormal refrigerant temperature rise and refrigerant pressure drop in the refrigeration cycle that occur due to this, the compressor that circulates the refrigerant in the refrigeration cycle is stopped, thereby preventing a decrease in refrigerant. If there is a difference between the time it takes for the pressure to drop below a predetermined value and the time it takes for the temperature to rise above a predetermined value due to the The detection parts complement each other, making it possible to reliably stop the compressor. Additionally, even if one of the pressure sensing part and temperature sensing part fails, they complement each other as described above, so if the amount of refrigerant decreases, the compressor can be stopped reliably. can. Furthermore, whereas in the past, a temperature switch and a pressure switch were separately provided in the refrigeration cycle to detect abnormal temperature rises and pressure drops, the device of the present invention has a simple configuration. , a similar effect can be achieved with one device. This makes it possible to protect the compressor more completely with good workability and at low cost.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a refrigeration cycle, Fig. 2 is a perspective view showing a state in which the compressor protection device according to the present invention is assembled into a liquid tank, and Figs. 3 to 5 are sectional views of the compressor protection device according to the present invention. be. 1... Compressor, 5... Liquid tank,
10... Compressor protection device, 11... Device main body, 13... Lid body, 14... Diaphragm, 15
... Spring chamber, 16 ... Actuation piece, 16a ... Movable contact, 17 ... Fixed contact, 17a, 17b ... Terminal, 19 ... Coil spring (spring member), 21 ...
Refrigerant chamber, 22...bimetal, 23...hole.

Claims (1)

[Scope of utility model registration request] A lid body 13 to which a diaphragm 14 is attached is attached to a device main body 11 provided with a fixed contact 17 and an actuating piece 16 having a movable contact 16a that contacts the fixed contact 17, and the lid body 13 and the diaphragm 14 are connected to each other. A hole 2 bored in the lid 13 between
The diaphragm 14 forms a refrigerant chamber 21 into which the refrigerant in the refrigeration cycle flows through the diaphragm 14.
A spring chamber 15 is formed between the spring chamber 15 and the device main body 11, and a spring chamber 15 is applied to the actuating piece 16 so that the movable contact 16a is separated from the fixed contact 17. A spring member 19 that provides a resilient force toward the diaphragm 14 is attached to the device main body 11.
An elastic force directed toward the spring chamber 15 is applied against the elastic force of the spring member 19, and the temperature inside the refrigerant chamber 21 causes the diaphragm 1 to
A bimetal 22 that deforms in a direction to release the elastic force on the refrigerant 4 is installed in the refrigerant chamber 21, and the compressor 1 is stopped by detecting an increase in the temperature of the refrigerant or a decrease in the pressure of the refrigerant. Compressor protection device.