JPH0428961A - Freezer device - Google Patents

Abstract

PURPOSE:To enable a capacity of a compressor to be coincided with a load of an evaporator, i.e., a freezing load irrespective of a length of a refrigerant pipe to connect the evaporator with the compressor by a method wherein means for determing a degree of opening of a control valve in response to a load of the compressor is provided and a degree of opening of the control valve determined in response to a length of the refrigerant pipe to connect the evaporator with the compressor is corrected. CONSTITUTION:A length of a refrigerant pipe connecting an evaporator 33 with a compressor 30 is inputted from an input means 68 to a degree-ofopening correction means 66, where a degree of opening determined by a degree-of- opening determining means 64 is corrected in accordance with a control rule to be inputted from a memory means 67. The corrected degree of opening is outputted to the control valve 36 through an output means 45 and the control valve 36 has a corrected degree of opening. Accordingly, the compressor is operated at a load of the evaporator, i.e. a capacity corresponding to the freezing load irrespective of a length of the refrigerant pipe connecting the evaporator with the compressor.

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 and its L1! title) In this type of refrigeration system, refrigerant discharged from a compressor passes through a condenser, a throttling mechanism, and an evaporator in this order, and is circulated to the compressor.

In this refrigeration system, if the capacity of the compressor does not match the refrigeration load, frost may adhere to the evaporator or the evaporation pressure of the refrigerant may become too low, resulting in deterioration of the operating efficiency.

To deal with this, impark is used to continuously and steplessly control the rotation speed of the compressor, that is, the capacity of the compressor, by changing the frequency of the current supplied to the drive motor of the compressor. However, this had the problem that the price of the inverter would become excessive as the capacity of the compressor increased.

In addition, if the temperature or pressure of the refrigerant gas sucked into the compressor, that is, the load on the compressor, is detected and the capacity of the compressor is controlled accordingly, the refrigerant piping connecting the evaporator and compressor can be controlled. If the length is long, there is a problem in that the flow resistance when the refrigerant gas flows through the refrigerant pipe increases, making it impossible to adjust the capacity of the compressor to the refrigeration load.

(Means for Solving the Problems) The present invention was invented to solve the above problems, and its gist is that the refrigerant discharged from the compressor is A refrigeration system in which the compressor is circulated through the compressor in this order is provided with a capacity control mechanism that can continuously and steplessly change the capacity of the compressor by controlling the opening degree of a control valve, and means for determining the opening degree of the control valve according to the load of the machine;
The refrigeration system is characterized in that it includes a control device including means for correcting the determined opening degree of the control valve in accordance with the length of the refrigerant pipe connecting the evaporator and the compressor.

<Function> Since the present invention has the above configuration, the opening degree of the control valve determined according to the load of the compressor is corrected according to the length of the refrigerant pipe connecting the evaporator and the compressor. Therefore, regardless of the length of the refrigerant pipe connecting the evaporator and compressor, the compressor is operated at a capacity corresponding to the evaporator load, that is, the refrigeration load.

Embodiment One embodiment of the invention is shown in FIGS. 1-3.

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

The high-temperature, high-pressure refrigerant gas discharged from the 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 mechanism 32 consisting of a capillary tube, an expansion valve, etc., where it is throttled and adiabatically expanded to become a gas-liquid two-phase. Then,
This refrigerant enters the evaporator 33 where it is vaporized into a low temperature gaseous refrigerant and then circulated to the compressor 30.

A bypass pipe 35 that connects a working chamber of a variable capacity mechanism built into the compressor 30, which will be described later, and a suction pipe 34 of the compressor 30.
A control valve 36 is interposed therein.

A sensor 61 that detects the pressure or temperature of the refrigerant gas flowing inside the suction pipe 34 and a sensor 37 that detects the flow rate of this refrigerant are attached to the suction pipe 34.
The output is input to the controller 40.

Further, the length of the refrigerant pipe connecting the evaporator 33 and the compressor 30 is input to the controller 40 by the human power device 68 . The opening degree of the control valve 36 is controlled by a command from the controller 40, and the driving motor 39 of the compressor 30 is started or stopped.

A capacity control mechanism for compressor 30 is shown in FIG.

In Fig. 3, l is a cylinder, 2 is a piston, 3 is a valve plate, 4 is a cylinder head, 5 is a suction cavity, 6 is a suction valve, 7 is a discharge valve, 8 is a discharge chamber, 9 is an unloader cylinder, 10 is a An unloader piston, 23 is a seal ring, 25 is a piston link, and 26 is a washer.

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.
A working chamber 16 is defined above the unloader piston 10, and a chamber 19 is defined below the unloader piston 10 by fitting the unloader piston 10 in a sealed and slidable manner. This chamber 19 communicates with the gas compression chamber 12 through the opening 18, and the working chamber 16 is connected to the cover 20.
It communicates with the discharge chamber 8 through a throttle hole 24 bored in the discharge chamber 8 . Further, the working chamber 16 communicates with the bypass pipe 35 via the pressure guiding pipe I5 and a passage 821 bored in the valve plate 3.

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, pushing the discharge valve 7 and causing σr1 to flow through llPt13.
The liquid passes through the discharge chamber 8 and is discharged from there through a discharge pipe (not shown).

On the other hand, the gas in the gas compression chamber 12 flows into the chamber 19 through the opening 18, and the discharge gas in the discharge chamber 8 flows into the working chamber 16 through the throttle hole 24. Then, the gas in the working chamber 16 flows out into the suction pipe 34 of the compressor 30 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 by the control valve 36, the pressure within the working chamber 16 is set to an arbitrary pressure.

(Thus, the unloader piston 10 moves up and down according to the difference between the pressure in the working chamber 16 and the average cylinder pressure in the gas compression chamber 12 acting on the chamber 19. Then, the chamber 19 and the opening 18 The top clearance volume constituted by this changes, and the capacity of the compressor 30 changes continuously and steplessly accordingly.

A functional block diagram of controller 40 is shown in FIG.

The refrigerant gas temperature or pressure detected by the sensor 61 is input to the comparison means 62 of the controller 40, and is compared here with the set value set in the setting means 63 to calculate the deviation between the two. This deviation is input to the opening determining means 64, where the opening of the control valve 36 is determined according to the control rule input from the storage means 65. Note that t9 means 6
5 stores control rules (for example, PID control, table comparison control, fuzzy control, etc.) for determining the opening degree in accordance with the deviation and its rate of change. The determined opening degree is input to the opening degree correction means 66.

On the other hand, the length of the refrigerant pipe connecting the evaporator 33 and the compressor 830 is input from the input means 68 to the opening correction means 66, and the opening determined by the opening determining means 64 is recorded in the opening correction means 66.
It is corrected according to the control rule input from 7. Then, the corrected opening degree is outputted to the control valve 36 via the output means 45, and the control valve 36 has the corrected opening degree.

On the other hand, the flow velocity of the refrigerant gas detected by the sensor 37 is input to the comparison means 47 of the controller 40, where it is compared with the set value input from the setting means 48.

When the flow rate of the refrigerant falls below the set value due to a decrease in the load on the pressure 1Iiia 30, the refrigerant is transferred to the compressor 3 via the output means 49.
A stop command is output to the drive motor 39 of No. 0, and the compressor 30 is stopped. After the operation is stopped, when a certain period of time has elapsed or when the refrigerant pressure in the suction pipe 54 exceeds a predetermined value, the motor 39 is started by a command from the controller 40, and the operation of the compressor 30 is restarted.

In the embodiment described above, the flow rate of the refrigerant is detected by the sensor 37, but the rotation speed of the compressor 30, the electric power supplied to the motor 39, etc. may be detected instead.

(Effects of the Invention) In the present invention, in order to correct the opening degree of the control valve determined according to the load of the compressor according to the length of the refrigerant pipe connecting the evaporator and the compressor, It becomes possible to match the capacity of the compressor to the load of the evaporator, that is, the refrigeration load, regardless of the length of the refrigerant pipe connecting the compressor to the evaporator.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, FIG. 1 is a system diagram, and FIG. 2 is a system diagram.
The figure is a functional block diagram of the controller, and FIG. 3 is a vertical sectional view of the variable capacity mechanism of the compressor.

Claims (1)

[Claims] In a refrigeration system in which refrigerant discharged from a compressor passes through a condenser, a throttle mechanism, and an evaporator in this order and circulates to the compressor, the capacity of the compressor can be continuously adjusted by controlling the opening degree of a control valve. and a means for determining the opening degree of the control valve according to the load of the compressor, and a length of refrigerant piping connecting the evaporator and the compressor. A refrigeration system comprising a control device including means for correcting the opening degree of the control valve determined as described above.