JPH01273886A - Control unit of compressor - Google Patents

Abstract

PURPOSE:To average the use frequency and equalize the abrasion degree of each compressing air cylinder by switching so as to have the road priority of each compressing air cylinder circulated every set time of compressive motion. CONSTITUTION:A compressor 1 is provided with, for instance, four compressing air cylinders 2a-5a, and each of the compressing air cylinders 2a-5a is provided with unloaders 2-5. Electromagnetic valves 21-24 are further provided corresponding to the respective unloaders 2-5. Each of the electromagnetic valves 21-24 connects conduit lines 25-28 leading to the unloaders 2-5 to any one of a group of conduit lines 29-32 leading to an inlet 8 and a group of conduit lines 33-36 leading to an outlet 9. Each of the electromagnetic valves 21-24 are electrically controlled by a control unit 40. The control unit 40 has timers T1-T4, and the operation priority of the four electromagnetic valves 21-24 is to be circulated corresponding to each of the timers T1-T4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device applied to a compressor with variable compression capacity such as a compressor for a heat pump, and in particular to This invention relates to a control device for

(Prior art) Conventionally, air conditioners such as heat pumps and coolers, or compressors such as near compressors, are equipped with multiple compression cylinders (cylinder piston type or rotary type). Some compressor capacity can be varied by changing the number of loads on the compression cylinder.

For example, an example of a compressor for a heat pump is shown in FIG. This compressor 1 has four compressed air n2a.

3a, 4a, 5a (paths shown) are provided at the bottom of the unloader, and an unloader 2, 4.5 is attached to each of the three compression cylinders 2a, 4a, 5a among these compression cylinders. This unloader 2.4.5 functions to switch between loading and unloading of each compression cylinder, and is controlled by gas pressure. The control gas pressure supplied to these unloaders 2°4.5 is 2.
This is done by electrical control of two solenoid valves 6.7. One of the solenoid valves 6 is a conduit 11 leading to the unloader 2.4, a conduit 10 leading to the suction port 8, or a conduit 1 leading to the discharge port 9.
2. Further, the other solenoid valve 7 connects a pipe line 14 leading to the unloader 5 to a pipe line 1 leading to the suction port 8.
3 or the conduit 15 leading to the discharge port 9. The suction port 8 is on the low pressure side, and the discharge port 9 is on the high pressure side.

With this configuration, the two unloaders 2 and 4 are controlled by switching the Ti solenoid valve, and the unloader 5 is controlled by switching the solenoid valve 7, thereby increasing the number of loads of the compressor cylinders to be driven from 1 to 4. It can be set to any one of these, and the compression capacity can be adjusted accordingly.

(Problem to be Solved by the Invention) However, the conventional compressor 9 has a configuration in which the compression capacity is switched by loading a predetermined combination of compression cylinders, as in the compressor 1 illustrated above. Therefore, when the compression capacity is switched, the frequency of use of each compression cylinder differs, and the compression cylinder that is used more frequently will wear out faster.

For example, in the case of the illustrated compressor 1, the compression cylinder 3a, which is not provided with an unloader, is always driven, so this compression cylinder 3a is used most frequently and has the shortest lifespan. On the other hand, since the compression cylinder 5a provided with the unloader 5 is driven only when the cylinder is at maximum capacity, the side is also used less frequently and has the longest life.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a compressor capable of changing the compression capacity by switching the number of loads of a plurality of compression cylinders, In a compressor control device that controls the number of loads, each compression cylinder is provided with an unloader that independently loads and unloads each of the compression cylinders, and the unloader is controlled to control the number of times the compression operation is performed for a certain period of time. The present invention is characterized in that it includes a load order switching means for cyclically switching the load priority order of each compression cylinder.

(Operation) As described above, the present invention switches the compression capacity by controlling the unloader provided for each compression cylinder and switching the number of loads of the compression cylinders.

In addition, the present invention averages the frequency of use of each compression cylinder and equalizes the degree of wear of each compression cylinder by switching the load priority of each compression cylinder in a cyclic manner every fixed compression operation time. be able to.

<Embodiment> FIG. 1 is a schematic diagram of an embodiment of the present invention. This embodiment shows an example in which the present invention is applied to a compressor 1 for a heat pump similar to the conventional example shown in FIG. 4.

In this embodiment, there are four compression cylinders 2a, 3a, and 4a.

Unloaders 2 to 5 are provided on each of 5a (path shown),
Furthermore, the solenoid valves 21 to 21 correspond to each unloader 2 to 5.
24 is provided. And each solenoid valve 21-2
4 leads to the unloaders 2 to 5 (passage 5 shown in FIG.
pipes 29 to 32 communicating with the suction port 8 or pipes 33 communicating with the discharge port 9
~36. And each solenoid valve 21~
24 is electrically controlled by a control device 40.

The unloaders 2 to 5 are constructed as shown in FIGS. 2 and 3.

In the figure, the unloader 42 is attached above the compression cylinder 61. An intake port 5 is provided on the upper side of the compression cylinder 61.
2 is formed, and this intake port 52 is provided with a valve spring 46.
A suction valve 48 is provided which is urged upward by the suction port 52 and opens and closes the suction port 52. This suction valve 48 opens during suction to introduce refrigerant into the compression cylinder 61 . A through hole 60 is formed in the bottom plate 53, and a discharge port 4 is formed on the bottom plate 53.
9 and a discharge valve 47 that opens during discharge.

The unloader 42 has a passage 50 that communicates with one of the electromagnetic valves 21 to 24, an unloader piston 43 that is urged downward by an unloader spring 44, and is formed on the lower surface of the unloader piston 43 that communicates with the passage 50. and a lift bin 45 which is disposed so as to abut against the lower surface of the peripheral edge of the unloader piston 43 and is biased upward by a spring 54.

Then, when the pressure of the suction port 8 is applied to the passage 50,
Since the pressure in the cylinder chamber 51 decreases, the unloader piston 43 descends as shown in FIG. Therefore, the lift bin 45 is pushed down by the unloader piston 43, and its lower end presses the suction valve 48. Thereby, the suction valve 48 is fixed in a state in which the suction port 52 is opened.

That is, in this state, the compression cylinder 61 is in an unloaded state.

On the other hand, when the pressure of the discharge port 9 is applied to the passage 50, the pressure of the cylinder chamber 51 increases, so that the unloader piston 43 rises as shown in FIG. Therefore, the lift bin 45 is moved upward by the urging force of the spring 54.
The suction valve 48 is made freely movable. This allows the suction valve 48 to open and close. That is, in this state, the compression cylinder 61 is in a loaded state.

Next, the control device 40 performs on/off control of the electromagnetic valves 21 to 24 so that the usage time of each compression cylinder 2a to 5a is averaged. This will be explained in detail below.

The control device 40 has four timers T1. T2. T3, T4
It is equipped with These timers T1 to T4 are timers that measure a certain period of time T, and in the event of a power outage, they memorize the time measured at that point, and the next time the power is turned on, they continue the time measurement operation from the memorized time. (This is called a power failure memory type timer.) While the compressor 1 is operating, one of the timers is always operating.

That is, the timer T1 operates first and measures a certain time T, then the timer T2 operates, and when the timer T2 measures a partial time T, the timer T3 operates next.

Similarly, when the timer T3 measures a partial time T, the timer T4 then operates to measure a -fixed time T, and when this timing operation is completed, the timer T1 operates again. That is,
The timer, which operates in a circular manner, switches as follows: T1→T2→T3→T4→T1→...

The priority order for operating the electromagnetic valves 21 to 24 is determined in correspondence with each of the timers T1 to T4. That is, (1) The operation vJ@ of timer T1 includes: ■ Solenoid valve 21 ■ Solenoid valve 22 ■ Solenoid valve 23 ■ Solenoid valve 2
4 (2) When timer T2 is activated, ■Solenoid valve 22 ■Solenoid valve 23 ■Solenoid valve 24 ■Solenoid valve 2
1 (3) When timer T3 is activated, ■Solenoid valve 23 ■Solenoid valve 24 ■Solenoid valve 21 ■Solenoid valve 2
2 (4) When timer T4 is activated, ■Solenoid valve 24 ■Solenoid valve 21 ■Solenoid valve 22 ■Solenoid valve 2
Priorities are determined such that the four electromagnetic valves 21 to 24 are circulated as shown in FIG. Here, the priority is the order that determines which compression cylinder is to be operated with respect to the compression capacity that is switched in four stages.

For example, when the timer T1 is activated and the compression capacity is maximized, all four compression cylinders are activated, so all solenoid valves 21 to 24 are turned on (here, on means that the unloaders 2 to 5 are turned on). This refers to the state in which the solenoid valve is operated so that the discharge port 9 communicates with the pipes 25 to 28, and at this time the compression cylinder is in a loaded state.

In addition, in order to make the compression capacity 3/4 of the maximum, it is sufficient to operate three of the four compression cylinders, so the solenoid valves 21 to 23 of priority order ■ to ■ are turned on. Similarly, when the compression capacity is 1/2 of the maximum, the solenoid valves 21 and 22 with the priority order ■ and ■ are turned on, and when the compression capacity is 1/4 of the maximum, the solenoid valve 21 and 22 with the priority order Turn on only 21.

Therefore, for example, assuming that the timer time T is 1 hour,
When operating at 1/2 compression capacity, the solenoid valves that are turned on every hour are solenoid valves 21 and 22 → solenoid valves 22 and 23.
→ Solenoid valve 23.24 → Solenoid valve 24, 21 → Solenoid valve 21.
It is switched cyclically as 22→... As a result, the frequency of use of each compression cylinder is averaged, and there is no imbalance in the frequency of use unlike in the conventional system.

Further, during operation on day 1, the compression capacity often changes depending on the time, but due to the circulation of priorities as described above, the frequency of use of each compression cylinder is averaged over a long period of use.

The unloaders 2 to 5 are not limited to those operated by gas pressure, but may be operated by hydraulic pressure.

The present invention also applies to air conditioners such as heat pumps and coolers,
It is clear that the present invention can be widely applied to compressors such as near compressors and refrigerant pressure IB refrigerant compressors for refrigerators, in which the compression capacity can be varied by changing the number of loads in a plurality of compression cylinders.

(Effects of the Invention) As described above in detail, the present invention provides an unloader for each compression cylinder having a plurality of compression cylinders, and controls these unloaders to switch the number of loads of the compression cylinders. In addition to switching the compression capacity using The degree of wear can be made even.

Moreover, since the present invention can control each compression cylinder independently,
A higher level of control becomes possible. For example, the priority order of the compression cylinders can be cyclically controlled in conjunction with the control of the rotational speed of a power machine that rotates the compressor. In this way, the efficiency of the power machine can be improved and the life of both the power mode and the compression mode can be extended.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIGS. 2 and 3 are sectional views showing the configuration and operation of an unloader in the same embodiment, and FIG. 4 is a schematic configuration diagram of a conventional example. . 1... Compressors 2-5, 42... Unloaders 2a-5a, 61... Compression cylinders 21-24...
... Solenoid valve 40 ... Control equipment

Claims (1)

[Scope of Claims] A compressor control device that is installed in a compressor capable of changing compression capacity by switching the number of loads of a plurality of compression cylinders, and controls the number of loads of the compression cylinders, comprising: Each compression cylinder is provided with an unloader that loads and unloads each compression cylinder independently, and the unloader is controlled so that the load priority of each compression cylinder is cycled each time a compression operation is performed for a certain period of time. A compressor control device comprising load order switching means.