JPH10220884A - Screw refrigerator unit - Google Patents

Abstract

(57) [Problem] To provide an energy-saving refrigerator unit in which a maximum current value at the time of starting a succeeding machine is kept small in a multi-type refrigerator unit in which a plurality of screw compressors having different capacities are mounted. A starting order of a large-capacity compressor 1 and a small-capacity compressor 2 is set as a large-capacity compressor as a first starter and a small-capacity compressor 2 as a subsequent starter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor, an oil separator, and two or more screw compressors having different capacities.
The present invention relates to a multi-type screw refrigerator unit including an oil tank, an oil cooler, and the like.

[0002]

2. Description of the Related Art Japanese Patent Application No. 3-283061, "Multi-Type Refrigerator", does not disclose the starting order of a plurality of mounted compressors.

[0003] Japanese Utility Model Laid-Open No. 51-79065, "Parallel compression refrigeration system" does not describe the different capacities and the starting order of a plurality of mounted compressors.

Japanese Unexamined Patent Publication No. 62-87770 "Refrigeration apparatus" describes a method of equalizing an oil amount and extending an interval of oil leveling operation for a plurality of compressors. There is no mention of the boot order.

Japanese Patent Application Laid-Open No. 5-332645 discloses a co-generation type refrigerating apparatus in which a plurality of refrigerating machines are provided with a commercial power source and a generator. No mention is made of the different capacity of the compressor and the starting sequence.

In Japanese Unexamined Patent Publication No. 4-80555 "Refrigeration apparatus",
This document describes that a plurality of compressors are equipped with oil equalizing pipes to hold oil balance plugs between the compressors, but does not describe the different capacities of the compressors and the order of startup.

[0007]

SUMMARY OF THE INVENTION In a multi-type screw refrigerator unit equipped with one large-capacity compressor and two small-capacity compressors and two different-capacity screw compressors, the compressor started at the head (No. 1) It is an object of the present invention to reduce the maximum current value when the subsequent compressor (No. 2) is started after the rated operation, save power consumption, and save energy.

The same applies to a multi-type screw refrigerator unit equipped with three or more screw compressors of different capacities.

[0009]

The above object can be achieved by the following technical means. (1). In a multi-type screw refrigerator unit equipped with two large-capacity compressors and one small-capacity compressor and two different-capacity screw compressors, a large-capacity compressor (No. 1 ) Is the top-starting compressor, and the small-capacity compressor (Unit 2) with a small starting current value is arranged in the subsequent-compressing compressor. , The maximum current value at the time of startup of the small capacity compressor (No. 2) can be suppressed to be small, power consumption can be saved, and energy can be saved.

(2) The same applies to a multi-type screw refrigerator equipped with three or more screw compressors of different capacities.
Same as (1).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2 and 3 are cycle system diagrams of a multi-type screw refrigerator equipped with two or three screw compressors having different capacities according to an embodiment of the present invention. FIG. 4 is a block diagram showing the startup sequence of a multi-type screw refrigerator unit equipped with one large capacity compressor and two small capacity compressors and two different capacity compressors.

This multi-type screw refrigerator has two or three screw compressors of different capacities, and includes a condenser,
The system includes an oil separator, an oil tank, and an oil cooler.

The cycle system diagram of FIG. 1 will be described.
A multi-type screw refrigerating machine equipped with two different capacity compressors, a large capacity compressor 1 and a small capacity compressor 2. The starting order of the compressors is as follows. 2 is set as the succeeding machine.

Next, the configuration and operation of the refrigeration cycle will be described.

[0015] The refrigerant gas sucked into the large capacity compressor 1 and the small capacity compressor 2 through the suction strainers 3 and 4 is:
It is compressed and enters the oil separator 7 from the discharge pipes 5 and 6, passes through the oil separator 8, and flows into the coagulator 10 via the discharge pipe 9.

On the other hand, the oil 11 contained in the refrigerant gas is separated when passing through the oil separating device 8 and accumulates in the oil tank 13 via the oil outlet pipe 12. The oil 11 in the oil tank 13 is the oil pipe 1
4 and flows into an oil cooler 15 where it is cooled and supplied to an oil supply pipe 16.
As a result, the oil passes through the oil strainer 17, passes through the oil supply control solenoid valve 18, and is supplied from the oil supply ports 19 and 20 to the large capacity compressor 1 and the small capacity compressor 2.

The cycle system diagram of FIG. 2 will be described.
Large capacity compressor 1, Medium capacity compressor 21 and Small capacity compressor 2
In this multi-type screw refrigerator equipped with three different capacity compressors, the starting order of the compressors is as follows: the large capacity compressor 1 is the first starter, and the succeeding machines are the medium capacity compressor 21 and the small capacity compressor 2. They are set in order.

FIG. 1 is an illustration of the structure and operation of the refrigeration cycle.
Is the same as

The cycle system diagram of FIG. 3 will be described.
Two large capacity compressors 1, two medium capacity compressors 21, one same capacity compressor, one different capacity compressor and one different capacity compressor 3.
In the multi-type screw refrigerating machine equipped with a stand, the starting order of the compressors is set such that the large-capacity compressor 1 is the first starting compressor, and the large-capacity compressor 1 and the medium-capacity compressor 21 are set as the succeeding compressors.

FIG. 1 is an illustration of the structure and operation of the refrigeration cycle.
Is the same as

The starting sequence will be described with reference to the block diagram of FIG.

This refrigerator unit is a multi-type screw refrigerator unit equipped with one large capacity compressor and one small capacity compressor and two different capacity compressors as shown in the cycle diagram of FIG.

Here, the large-capacity compressor is referred to as Unit 1 and the small-capacity compressor is referred to as Unit 2.

When the start pushbutton switch is pressed, the time relay for the first unit is energized, and the first unit is started as the first unit by the operation command by the operation of the temperature controller for the first unit, and the rated operation is continued.

The time-limit relay for Unit 2 is energized at the same time as the start-up of Unit 1, and when the set time elapses, for example, the set time of the time-limit relay for Unit 1 is set to 5 minutes, and the set time of the time-limit relay for Unit 2 is set to If you set 7 minutes, the start of Unit 2 will be 1
Two minutes after the start of the unit, the subsequent start is performed by the operation command by the operation of the temperature controller for the second unit, and the compressors of the first and second units both continue the rated operation at full load.

When the internal temperature falls below a predetermined temperature,
The subsequently started temperature controller for Unit 2 operates, and the operation of Unit 2 is stopped. When the temperature in the refrigerator further decreases, the temperature controller for the first unit operates to stop the operation of the first unit. Here, the set temperature of the first-unit temperature controller is set to a lower value than that of the second-unit temperature controller. For this reason, the order of the stop is the second unit first.

In the case of restart, the time limit relay of the first unit is 5
Minutes, the first unit starts up 5 minutes after the stoppage, and the second unit starts 2 minutes after the first unit starts up.
Starts after a minute.

Accordingly, the start order is always the first start-up and the second start-up following the setting of the time relay.

As described above, in a multi-type screw refrigerating machine equipped with a plurality of compressors of different capacities, a large-capacity compressor is provided for the first starter and a small-capacity compressor is provided for the subsequent starter. The maximum current value at the time of startup of the small capacity compressor of the compressor can be reduced, and an energy-saving multi-type screw refrigerator unit with reduced power consumption can be provided.

[0030]

The effects of the present invention in a multi-type screw refrigerator unit equipped with a plurality of compressors of different capacities are described below.

(1) In a multi-type screw refrigerator unit equipped with one large-capacity compressor and two small-capacity compressors and two different-capacity compressors, the starting order of the compressors is changed to the large capacity as the first starting machine. By setting the small-capacity compressor as the compressor and the subsequent starter, it becomes possible to suppress the maximum current value of the small-capacity compressor of the subsequent starter at the time of starting, thereby saving power consumption.

(2) By arranging a large-capacity compressor at the head starter, the capacity becomes 60 to 70% of the total load capacity, and the frequency of operation and stop at low load is reduced. Economical driving can be obtained.

[Brief description of the drawings]

FIG. 1 is a cycle system diagram of a multi-type screw refrigerator unit equipped with one large capacity compressor and two small capacity compressors and two different capacity compressors.

FIG. 2 is a cycle system diagram of a multi-type screw refrigerator unit equipped with three different capacity compressors each having one large capacity, medium capacity, and small capacity.

FIG. 3 is a cycle system diagram of a multi-type screw refrigerator unit equipped with two large capacity compressors and one medium capacity compressor and three different capacity compressors.

FIG. 4 is a block diagram showing a startup sequence of a multi-type screw refrigerator unit equipped with one large capacity compressor and one small capacity compressor and two different capacity compressors.

[Explanation of symbols]

1 large-capacity compressor, 2 small-capacity compressor, 7 oil separator,
10: condenser, 13: oil tank, 15: oil cooler, 21
… Medium capacity compressor.

Claims (6)

[Claims] A compression element composed of a pair of male and female low-stage screw rotors and a pair of male and female high-stage screw rotors that rotate while meshing with the motor elements of the stator and the rotor, and disassembled. A two-stage screw compressor built in a possible closed casing, a large capacity compressor 1
In a multi-type screw refrigerator equipped with two units and one small capacity compressor and two different capacity compressors, the startup sequence is that the large capacity compressor is used as the first starter and the small capacity compressor is used as the subsequent starter. And a screw refrigerator unit. 2. A multi-type screw refrigerator according to claim 1, wherein three large capacity, medium capacity, and small capacity compressors each having three different capacity are mounted. Multi-type screw chiller unit with medium capacity compressor and small capacity compressor in the order of subsequent starter. 3. A single-stage screw compressor incorporating a pair of male and female screw rotors, one large capacity compressor and one small capacity compressor and two different capacity compressors according to claim 1. Multi-type screw refrigerator unit. 4. A multi-type screw refrigerator unit according to claim 2, wherein three single-stage screw compressors of different capacity are mounted. 5. A large-capacity two-unit according to claim 2, wherein
In a multi-type screw refrigerator equipped with three small-capacity screw compressors, the start-up sequence is as follows: large-capacity compressor for the first boot, large-capacity compressor for the second boot, and medium-capacity compressor. A multi-type screw refrigerator unit characterized by the following. 6. A multi-type screw refrigerator unit according to claim 2, 4 or 5, wherein four or more screw compressors are mounted.