JPH02192544A - Freezer device - Google Patents

Abstract

PURPOSE:To cause a capability of a compressor to be continuously varied in stepless manner according to a freezing load by a method wherein a working chamber communicates with a suction side of a compressor through a bypassing pipe and a control valve of which degree of opening is controlled according to a pressure or a temperature of refrigerant at a suction side of the compressor is installed at this bypassing pipe. CONSTITUTION:A bypassing pipe 35 for connecting a compressor 30 with a suction pipe 34 is provided with a control valve 36. This control valve 36 is controlled for its degree of opening under an instruction from a controller 37. To this suction side pipe 34 is attached a sensor 38 for use in sensing either a pressure or a temperature of refrigerant flowing in the suction side pipe 34. A signal from this sensor 38 is inputted to a comparing means 39 of a controller 37, where it is compared with a set value set in a setting means 40 and then a difference between both values is calculated. This difference is inputted to means 41 for determining 42 and then a degree of opening corresponding to the difference is determined. The memory means 42 stores a predetermined degree of opening in correspondence with the difference in the table. This degree of opening is outputted to the control valve 36 through an outputting means 43 and the control valve 36 has this decided degree of opening.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to refrigeration equipment such as refrigerators, water coolers, air conditioners, and dehumidifiers equipped with reciprocating compressors.

(Prior Art) In this type of refrigeration system, during operation, refrigerant discharged from a compressor circulates through a condenser, a throttle device, and an evaporator in this order.

(Problems to be Solved by the Invention) In conventional refrigeration systems, the capacity of the compressor is usually larger than the refrigeration load (because it is selected to Not only does the operating efficiency deteriorate when the refrigeration load becomes too low, but when the refrigeration load fluctuates and falls below the operating range of the compressor, it is necessary to repeatedly start and stop the compressor.

To deal with this, it has been proposed to use an inverter to continuously control the compressor capacity by changing the frequency of the current supplied to the compressor;
When the capacity of one machine is large, there is a problem that the cost of the inverter becomes excessive. (Means for solving the problem) The present invention was invented in order to solve the above problem. The gist is that in a refrigeration system in which refrigerant discharged from a reciprocating compressor circulates through a condenser, a throttle device, and an evaporator in this order, the compressor is sealed and slidable in an unloader cylinder. an unloader piston fitted into the unloader piston, a chamber bounded on one side of the unloader piston communicates with the gas compression chamber of the compressor, and a working chamber bounded on the other side is connected to the suction side of the compressor. The refrigeration system is characterized in that the control valve communicates through a bypass pipe, and the bypass pipe is provided with a control valve whose opening degree is controlled depending on the pressure or temperature of the refrigerant on the suction side of the compressor.

(Function) Since the present invention has the above configuration, when the pressure or temperature of the refrigerant on the suction side of the compressor changes depending on the refrigeration load, the opening degree of the control valve automatically changes accordingly. The pressure inside the working chamber changes. As a result, the unloader piston moves within the unloader cylinder and the top clearance volume of the pressure wtm changes, so the capacity of the compressor changes steplessly and continuously in accordance with the refrigeration load.

(Example) One embodiment of the invention is shown in FIGS. 1 and 2.

FIG. 1 shows a system diagram of the refrigeration system.

The high-temperature, high-pressure refrigerant gas discharged from the compression compressor 30 enters the condenser 31 as shown by the arrow, where it is condensed and liquefied to become a high-pressure liquid refrigerant. This liquid refrigerant enters a throttling device 32 consisting of an expansion valve and the like, where it is throttled and adiabatically expanded to become a gas-liquid two-phase.

Next, this refrigerant enters the evaporator 33, where it is evaporated and turned into a low-temperature, low-pressure gas refrigerant that is circulated to the compressor 30.

A control valve 36 is interposed in a bypass pipe 35 that connects the compressor 30 and its suction side pipe 34, and the opening degree of this control valve 36 is controlled by a command from a controller 37. A sensor 38 is attached to the suction side pipe 34 to detect the pressure or temperature of the refrigerant flowing therein, and a signal from this sensor 38 is input to the comparison means 39 of the controller 37, where it is set in the setting means 40. It is compared with the set value and the deviation between the two is calculated. This deviation is input to the opening degree determination means 41, where it is compared with the table input from the storage means 42, and the opening degree corresponding to the deviation is determined. Note that the storage means 42 stores a table with predetermined opening degrees corresponding to the deviations. This opening degree is outputted to the control valve 36 via the output means 43, and the control valve 36 becomes the determined opening degree.

FIG. 2 shows a capacity control device for the reciprocating compressor 30.

In Fig. 2, ■ is the cylinder, 2 is the piston, 3 is the valve plate, 4 is the cylinder head, 5 is the suction cavity, 6 is the suction valve, 7 is the discharge valve, 8 is the discharge chamber, 9 is the unloader cylinder, 10 is the This is the unloader piston.

The lower end of the unloader cylinder 9 is fixed to the valve plate 3, and the upper end is covered by a cover 20.

An unloader piston 10 is placed inside this unloader cylinder 9.
By sealingly and slidably fitting the unloader piston 10, an operating chamber 16 is defined above the unloader piston 10, and a chamber 19 is defined below the unloader piston 10. And this chamber 19 has an opening 18
The working chamber 16 communicates with the gas compression chamber 12 through the gas compression chamber 12, and the working chamber 16 communicates with the discharge chamber 8 through a throttle hole 24 formed in the cover 20.
is connected to. Further, the working chamber 16 communicates with a bypass pipe 35 via a pressure guiding pipe 15 and a passage 21 bored in the valve plate 3 .

23 is a seal ring wound around the upper end of the unloader piston 10, 25 is a piston ring wound around the piston 2, and 26 is a washer fixed to the lower end of the unloader cylinder 9.

When the piston 2 moves back, the refrigerant gas passes through the suction passage 11 formed in the valve plate 3 from the suction cavity 5, pushes open the suction valve 6, and is sucked into the gas compression chamber 12.

When the piston 2 moves forward, the refrigerant gas in the gas compression chamber 12 is compressed, pushes the discharge valve 7 open, enters the discharge chamber 8 through the passage 13, and is discharged from there through a discharge pipe (not shown).

On the other hand, the average pressure in the gas compression chamber 12 acts on the chamber 19 through the opening 18, and discharge gas flows into the working chamber 16 from the discharge chamber 8 through the throttle hole 24, and the unloader cylinder 9 and unloader piston 10 High pressure gas flows in through the gap between the Then, the gas in the working chamber 16 flows out into the suction side pipe 34 through the pressure guiding pipe 15, the passage 21, the control valve 36, and the bypass pipe 35.

By controlling the flow rate of this gas using the control valve 36, the pressure within the working chamber 16 can be set to an arbitrary pressure.

Thus, the unloader piston 10 moves up and down depending on the difference between the pressure in the working chamber 16 and the average pressure in the gas compression chamber 12 acting on the chamber 19, and is configured by the chamber 19, the opening 18, and the gas compression chamber 12. The top clearance volume changes, and the capacity of the reciprocating compressor 30 changes accordingly.

(Effects of the Invention) In the present invention, the working chamber is connected to the suction side of the compressor via a bypass pipe, and the bypass pipe has a control valve whose opening degree is controlled depending on the pressure or temperature of the refrigerant on the suction side of the compressor. Because of this, when the pressure or temperature of the refrigerant on the suction side of the pressure m machine changes depending on the refrigeration load, the opening degree of the control valve automatically changes accordingly, and the pressure inside the working chamber changes. As a result, the unloader piston moves within the unloader cylinder and the top clearance volume of the compressor changes, so the compressor capacity changes steplessly and continuously according to the refrigeration load, thus increasing the refrigerant evaporation temperature. Since the frost can be retained, the operating efficiency of the refrigeration system can be improved, and since the amount of frost adhering to the evaporator is reduced, the number of defrosting operations can be reduced, contributing to energy saving.

Furthermore, since there is no need to frequently repeat the operation and stop of the compressor, the refrigeration system can be operated continuously.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a system diagram of a refrigeration system, and FIG. 2 is a partial vertical sectional view showing a capacity control device for a reciprocating compressor. Reciprocating pressure wJ machine - 30, condenser - 31, throttling device - 32, evaporator... 33, unloader cylinder...
-9, Unloader piston...10, Chamber...19, Gas compression chamber...12, Working chamber...16, Suction side piping...
34, Bypass pipe...-35, Control procedure correction 8 mark button 1. Display of the case 1999 patent application No. 009866 2, name of the invention Refrigeration device 3, person making the amendment Relationship to the case Patent applicant address 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Name (6
20) Mitsubishi Heavy Industries, Ltd. 4, Agent address: 18-15-6 Nishi-Shinbashi-chome, Minato-ku, Tokyo 0105
゜Heisei year, month, day correction is subject to calculation procedures (e.g., PID control, table comparison control,
fuzzy control, etc.) are stored. ” will be corrected.

Claims (1)

[Claims] In a refrigeration system in which refrigerant discharged from a reciprocating compressor circulates through a condenser, a throttle device, and an evaporator in this order, the compressor has an unloader cylinder and an unloader fitted into the unloader cylinder in a sealed and slidable manner. a piston, the unloader piston having a chamber bounded on one side communicating with the gas compression chamber of the compressor, and a working chamber bounded on the other side communicating with the suction side of the compressor via a bypass pipe; A refrigeration system characterized in that the bypass pipe is provided with a control valve whose opening degree is controlled depending on the pressure or temperature of the refrigerant on the suction side of the compressor.