JPH05228400A - Cooling controller of centrifugal machine - Google Patents

Abstract

PURPOSE:To inexpensively obtain temp. control with high accuracy by enabling the intermittent operations a refrigerator at short time intervals in the construction and control of the refrigerator of a centrifugal separator. CONSTITUTION:A bypass piping 9 via a switch 8 for connecting a high-pressure side piping with a low-pressure side piping is provided in the refrigerator constituted of a compressor 1, a condenser 1, an evaporator 3 and a throttle mechanism 7. The pressure difference between the high-pressure side piping A and the low-pressure side piping B as the factor to prohibit the start of the compressor 1 is rapidly removed by operating the switch 8. The intermittent operations at the short time intervals of the refrigerator are thus enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system and control for equipment such as a cooling centrifuge, which requires frequent intermittent operation of the cooling machine for temperature control.

[0002]

2. Description of the Related Art In a conventional refrigerator of a centrifugal separator, a temperature is controlled mainly by intermittently driving the refrigerator by using a reciprocating compressor.

[0003]

In the case of a refrigerating centrifuge, a refrigerator requires a low temperature and a large cooling capacity, and a hermetic compressor is usually used. The low temperature refrigerant R502 which has been used conventionally due to the recent Freon gas regulations is the year 2000
There is a problem of being abolished in a year. There is a relatively easy-to-obtain refrigerant R22 that is not subject to the CFC regulations and is a small, fully enclosed type and that can obtain a large cooling capacity at low temperature. However, a refrigerator for a refrigerant that meets the above conditions is a rotary compressor (rotary compressor). ) Had to choose from among them.

When controlling the temperature of the object to be cooled by using a refrigerator, there are methods such as intermittent operation control, hot gas bypass control, rotation speed control of the compressor by an inverter, and evaporation temperature control by an evaporation pressure adjusting valve. The intermittent operation method is the cheapest, and the other methods increase the cost due to complicated piping and the need for expensive control elements or control valves.

In the case of the rotary compressor, once it is stopped, it cannot be restarted unless there is a pressure difference between the high pressure side and the low pressure side of the cooling system. It takes about 3 minutes from the stop to the restart of the refrigerator. Fine temperature control by intermittent operation control was impossible. An object of the present invention is to control the temperature at low cost using a rotary compressor.

[0006]

The restart of the rotary compressor is hindered because it takes time for the high pressure side and the low pressure side of the cooling system piping to become uniform. Therefore, in order to obtain the intermittent operation similar to the conventional one, it is achieved by eliminating the pressure difference between the low pressure side and the high pressure side in a short time after stopping the rotary compressor.

[0007]

[Operation] Generally, a refrigerator using the Carnot cycle
It is a closed circulation system that causes a pressure difference due to the compressor and the throttle mechanism. A bypass pipe having a switch here is bypassed around the throttling mechanism and connected to the high-pressure side pipe and the low-pressure side pipe. As an operation, the switch is closed during the operation of the compressor, and when the refrigerator stops, the switch opens to eliminate the pressure difference in the bypass pipe in a short time and restart the compressor.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.
The sample 5 is housed in the rotating body 4 and rotationally driven by the drive unit 6. The heat generated by the rotational driving of the rotating body 4 is absorbed by the evaporator 3 arranged outside the rotating body 4, and is exhausted by the condenser 2 via the compressor 1. There is a temperature sensor 11 inside the evaporator 3, and the controller 10 measures the temperature inside the evaporator 3 and the controller 10 uses the data of the temperature sensor 11 so that the temperature of the sample 5 becomes the temperature specified by the user. The operation of the compressor 1 is controlled based on the relationship between the internal temperature and the temperature of the sample 5. The bypass pipe 9 having the switch 8 is provided in a shape bypassing the throttle mechanism 7, and connects the high-pressure side pipe and the low-pressure side pipe. FIG. 2 shows an operation diagram of the compressor 1 and the switch 8 and a pressure difference between the high-pressure and low-pressure side pipes. During operation of the compressor 1, the switch 8 is closed and the temperature of the evaporator 3 is lowered to cool the material of the rotating body 4. When the temperature data of the temperature sensor 11 becomes lower than the predetermined temperature, the control unit 10 stops the refrigerator 1 and opens the switch 8 to eliminate the pressure difference between the high pressure side pipe and the low pressure side pipe in a short time, 1. Make the pressure condition necessary for restart. When the temperature data of the temperature sensor 11 becomes higher than a predetermined temperature, the control unit 10 closes the switch 8 and the compressor 1
To operate. However, even if the temperature of the temperature sensor 11 becomes higher than a predetermined value, if there is a pressure difference between the high-pressure side pipe and the low-pressure side pipe, the compressor 1 causes a start-up failure, so the pressure difference between the high-pressure side pipe and the low-pressure side pipe is eliminated. The control unit 10 inhibits the operation of the compressor 1 for the time required for the time period a shown in FIG.

[0009]

According to the present invention, since the pressure difference between the high-pressure side pipe and the low-pressure side pipe of the refrigerator is eliminated in a short time, intermittent operation of the refrigerator can be performed at short intervals, and highly accurate temperature control is possible. Becomes

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a cooling system of a centrifugal separator according to the present invention.

FIG. 2 is an operation diagram showing an operation diagram of a compressor and a switch and a pressure difference between high and low pressure pipes.

[Explanation of symbols]

1 is a compressor, 2 is a condenser, 3 is an evaporator, 4 is a rotating body, 5
Is a sample, 6 is a driving unit, 7 is a diaphragm mechanism, 8 is a switch, 9 is a bypass pipe, 10 is a control unit, and 11 is a temperature sensor.

Claims (1)

[Claims] 1. A rotating body that stores a sample, a drive unit that drives the rotating body, and a cooling that absorbs heat generated by the driving of the rotating body and cools the sample stored in the rotating body. In a centrifugal separator having a machine, a rotary compressor is used as a cooler, and a bypass pipe having an operable switch is provided between a high-pressure side pipe and a low-pressure side pipe of the cooler, and the switch is operated. A cooling control device for a centrifuge, wherein the rotary compressor can be operated intermittently at short intervals.