JPS6146482A - Protector for compressor - Google Patents

Abstract

PURPOSE:To prevent contamination of steam and damage of a compressor, by detecting temperature of compressed steam concentrically in a discharge chamber at high and low temperature regions, and stopping operation of the compressor at abnormal high and low temperatures. CONSTITUTION:A temperature sensor 7 is constituted of a high temperature sensor and a low temperature sensor which are arranged adjacent to each other. Coefficient of thermal expansion of a metal piece A (bimetal) of the high temperature sensor is larger than that of B. Accordingly, when temperature increases, a rod 3 comes into contact with an upper switch spring. Coefficient of thermal expansion of a metal piece C of the low temperature sensor is smaller than that of D. Accordingly, when temperature decreases, a rod 4 comes into contact with a lower switch spring 2. Both the sensors are connected to each other to form a circuit leading from an electrode 8 to an electrode 9. There is defined an operational gap in the circuit near high and low set temperatures, and the gap is opened and closed according to temperature of compressed steam in a discharge chamber 15 to engage and disengage a clutch (not shown), thus controlling operation of a compressor. At abnormal high and low temperatures, the operation of the compressor is stopped to prevent contamination of the steam and damage of the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a compressor, particularly a compressor used in a vapor compression refrigeration cycle, in which the temperature of the compressor increases abnormally.
Or it relates to a protection device that prevents damage to a compressor due to abnormal descent.

BACKGROUND OF THE INVENTION Systems using vapor compression refrigeration cycles are typically controlled by cycling the compressor on and off.

In other words, a magnetic clutch is installed on the drive shaft of the compressor,
This club 1. For example, the temperature of the sky that is being frozen is turned on and off in response to the temperature of the sky. At this time, in order to prevent hunting caused by such closed circuit on/off control,
It is also well known to provide a dead zone (operating gap) of an appropriate size for the detected humidity. However, the above-mentioned structure is intended to provide excellent refrigeration, and is not intended to protect the compressor from damage.

If the compressor temperature becomes abnormally high, it will cause problems such as deterioration of the oil in the compressor and decomposition of the refrigerant, and if it becomes abnormally low, liquid refrigerant will be generated in the compressor, which may cause internal damage the next time it is started. There is a risk of it happening. In order to avoid operating the compressor at such abnormal temperatures, protection devices already exist, such as installing a temperature sensor on the inner surface of the compressor and turning off the clutch when the refrigerant temperature exceeds a set value.

Alternatively, there is already a protection device that installs a pressure detector in the high-pressure side piping downstream of pressure 1iit1 and turns off the clutch or prevents the clutch from turning on when the refrigerant vapor pressure is below a set value. There is.

Problems to be Solved by the Invention The above-mentioned protection device prevents the compressor from operating at abnormally high or low temperatures, and prevents steam contamination or damage to the compressor. It only works on either side of the Even if an attempt is made to operate at both high and low abnormal temperatures at the same time, simply assembling both would result in a complex and expensive device. The present invention aims to simultaneously prevent steam contamination, operation at abnormally high temperatures that may cause damage to the compressor, and operation at abnormally low temperatures, and to obtain a protective device that is simple in structure, reliable, and easy to manufacture. The purpose is

Means for Solving the Problem In order to achieve this object, in the present invention, a temperature sensor is attached to the compressor at a position where the temperature of the discharged steam of the compressor can be detected, and the detected temperature is higher than the set 111 high value. When the temperature rises or becomes lower than the set minimum value, a magnetic clutch provided on the compressor drive shaft is turned off to stop the compressor. In order to prevent hunting from occurring near the set value, an operating gap is provided between the set values.

Embodiment FIG. 3.4 shows an outline of a compressor to which the protection device of the present invention is applied.

The rotor 12 is made integrally with the shaft 10 and is rotatably supported via a bearing 13. The rotor 12 has vanes 3 attached thereto, and rotates within the cylinder 4 while bringing the vanes 3 into contact with the inner wall of the cylinder.

The rotor 12 is driven via a magnetic clutch and shaft 10 (not shown). Steam is drawn into the cylinder 4 through the inlet 21, and inside the cylinder 4,
It is compressed by rotation of a rotor 3 equipped with vanes 3.

The compressed steam passes through a discharge chamber 15, has oil separated therefrom by an oil separator 16, is discharged from a discharge port 22, and is guided to a condenser (not shown). Facing the discharge chamber 15, a temperature sensor 7 according to the invention is mounted.

FIG. 1 shows details of the temperature sensor 7. The detector 7 consists of a high temperature side detector and a low temperature side detector which are arranged adjacent to each other. The high temperature side detector is a double layer metal piece A
, B, an operating rod 3 fixed to the bimetal, and a two-position stable switch spring 1 operated by the rod 3.The thermal expansion coefficient of metal piece A is higher than that of B. As the temperature increases, the rod 3 moves upwards. Similarly, the low temperature side detector is composed of a bimetal having metal pieces C and D, an actuating rod 4, and a switch spring 2, and the expansion coefficient of metal piece C is D.
is smaller than that of , so that as the temperature drops the rod 4 moves downwards. By connecting both detectors in series, the circuit from electrode 8 to electrode 9 has a hysteresis region that operates near the high and low temperature set temperatures, as shown in Figure 2, and the circuit from the electrode 8 to the electrode 9 has a hysteresis region that operates in the vicinity of the high and low temperature set temperatures. It opens and closes depending on the compressed steam temperature. This circuit is inserted into the drive current circuit of the magnetic clutch described above, and controls the operation of the compressor by connecting and disconnecting the clutch.

Above, we have shown a temperature detector consisting of a pair of bimetals and a pair of two-position stable switches, but one thermistor is attached to the inner wall of the discharge chamber to detect the compressed steam temperature. It is also possible to set the temperature and open/close the circuit all electrically.

Effects of the Invention According to the present invention, the temperature of compressed steam is detected centrally in the discharge chamber, and is detected in both high and low temperature ranges, and the operation of the compressor is stopped when the temperature becomes abnormally high or abnormally low. Due to this, steam pollution and compressor loss10
can be prevented.

Furthermore, the device for this purpose is simple in structure and highly accurate.

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[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a first embodiment of the temperature sensor of the present invention, Fig. 2 is an explanatory diagram of the operation of the temperature sensor of Fig. 1, and Fig. 3 is a longitudinal cross-section of an example of a vapor compressor to which the present invention is applied. Figure 4 is a cross-sectional view taken along line IV-IV of Figure J53.

Claims (3)

[Claims] (1) As a protection device for a vapor compressor, the temperature of compressed steam is detected centrally near the discharge valve of the compressor cylinder, and the device is closed when the detected temperature is within a preset allowable temperature range for the compressor. A protection device that has a temperature sensor equipped with a circuit that becomes open when the temperature sensor enters the temperature range and leaves the range, and controls the operation of the compressor by opening and closing the circuit of the temperature sensor. (2) In the protection device according to claim 1,
A protection device characterized in that the circuit of the temperature detector opens and closes with an operating gap when the temperature rises and when the temperature falls, thereby preventing a hunting phenomenon of opening and closing. (3) In the protection device according to claim 1, the temperature sensor includes a high temperature side temperature sensor having a bimetallic temperature sensor and a two-position stable switch, and a bimetallic temperature sensor and a two-position stable switch. A protection device characterized in that it is configured by connecting in series a low-temperature side temperature sensor having a temperature sensor.