JPH04287880A - Connected compression device - Google Patents

Abstract

PURPOSE:To keep the oil level of each compressor in operation appropriately with simple structure by providing plural low pressure side sub-compressors to a master compressor forced to be on the high pressure side, and forming such structure as to move oil to the sub-compressor in operation from the master compressor through an oil balancing pipe without nonreturn mechanism even in the case of either one of the sub-compressors being stopped to cause the highest internal pressure of a casing in this stopped compressor. CONSTITUTION:Inlet branch pipes 26, 36 connected to sub-compressors 2, 3 run into an inlet main pipe 16 connected to a master compressor 1. Oil return is concentrated on the master compressor 1 on the high pressure side and oil balancing pipes 6, 7 are individually connected between the master compressor 1 and the respective sub-compressors 2, 3 to secure an oil moving passage to the sub-compressor in operation regardless of the pressure of the sub-compressor at a stop.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connected type compressor equipped with three or more compressors and suitable for relatively large-scale refrigeration systems such as building air conditioning systems.

0002

2. Description of the Related Art Conventionally, as this type of compression device, one disclosed in Japanese Patent Publication No. 36433/1983 is known.

As shown in FIG. 4, this device is equipped with first to third compressors A, B, and C each having a compression element P housed in a casing D having an oil sump O, and a distribution section of a main suction pipe H. An oil separator S is installed at the bottom, and a first suction branch pipe X connected to the first compressor A is installed at the bottom, and a second and third compressor B is installed at the top.
, C are connected to the second and third suction branch pipes Y and Z respectively, and the first compressor A is supplied with suction gas and oil, and the second and third compressors B and C are supplied with only suction gas. I'm trying to give it back. Then, the pressure loss of the first suction branch pipe X is made smaller than that of the second and third suction branch pipes Y and Z, and the first compressor A is used as the high-pressure side parent compressor and the second and third compressor B, C are forcibly divided into child compressors on the low pressure side, and an oil equalizing main pipe T extending from the parent compressor A is connected to an oil equalizing branch pipe K extending to each child compressor B, C.
, L, and move the oil from the high-pressure side main compressor A, where the oil concentrates and returns, to the low-pressure side child compressors B and C, so that the oil level in each compressor can be maintained at an appropriate level. There is.

[0004] Furthermore, if there is an operation stopper, regardless of the forced differential pressure based on the difference in pressure loss applied to each of the suction branch pipes,
The internal pressure of the stop machine becomes the highest, but when one of the low-pressure subcompressors B and C (for example, B), which does not return oil from the suction path, is stopped, the internal pressure of the stop machine B becomes the highest. The high pressure propagates from the oil equalizing branch pipe K to the oil equalizing main pipe T side, and the movement of oil to other child compressors C during continued operation is also obstructed. , check valves V and W are interposed to allow flow only from the parent compressor A side.

[0005]

[Problem to be Solved by the Invention] However, in the above system, check valves V and W are installed in the oil equalizing branch pipes K and L in order to eliminate the adverse effects associated with the stoppage of operation of the slave compressors B and C. Therefore, there is a problem that the number of parts increases and the connection structure of the oil equalizing pipe becomes complicated.

[0006] An object of the present invention is to provide a connected compression device that can achieve good oil-equalizing coupling of three or more compressors with a simple structure without intervening a check mechanism in the oil-equalizing pipe. There is a particular thing.

[0007]

[Means for Solving the Problems] Therefore, in order to achieve the above object, the present invention provides a connected system comprising three or more compressors 1, 2, and 3 each having a compression element inside a casing having an oil reservoir. In a type compression device, the internal pressure of the casing of one compressor 1 is reduced almost equally with the internal pressure of the casing of the other compressors 2 and 3, and one compressor is used as the main compressor 1 on the high pressure side. forced differential pressure means 4 for dividing the other plurality of compressors into child compressors 2 and 3 on the low pressure side;
The parent compressor 1 is provided with an oil return means 5 that returns more oil than the child compressors 2 and 3, and the parent compressor 1 is provided with a plurality of oil equalizing pipe connection ports, so that the parent compressor 1 and each of the child compressors 2 and 3, oil equalizing pipes 6 and 7 were individually connected.

Furthermore, with the above configuration, a connecting seat 8 having a plurality of oil equalizing pipe connecting ports is formed, and this connecting seat 8 is connected to the main compressor 1.
It is preferable to attach it to the casing.

[0009]

[Operation] Either of the slave compressors 2 and 3 on the low pressure side with a small amount of oil returned is stopped, and the internal pressure of the casing in this stopped machine becomes the highest pressure regardless of the differential pressure setting by the forced differential pressure means 4. In addition, oil is transferred from the parent compressor 1 to the other child compressors that are still in operation via an oil equalizing pipe that is connected separately from the oil equalizing pipe that is connected to the stop machine. The oil level in the compressor can be maintained at an appropriate level.

By attaching the connection seat 8 having a plurality of oil equalizing pipe connection ports to the casing 11 of the main compressor 1, the connection structure in the main compressor 1 to which a plurality of oil equalizing pipes 6 and 7 are connected can be simplified. It can be done.

[0011]

[Example] The connected compressor shown in Fig. 1 is a triple type equipped with three compressors, first to third compressors 1, 2, and 3. , scroll-type compression elements 12, 22, 32, and drive each compression element in closed low-pressure dome-shaped casings 11, 21, 31 having oil reservoirs 10, 20, 30 at the bottom, respectively. Motors 14, 24, and 34 having drive shafts 13, 23, and 33 are installed inside.

Discharge chambers 15, 25, 35 are defined in the upper part of each casing 11, 21, 31 to release the high pressure fluid compressed by each compression element 12, 22, 32,
First to third discharge branch pipes 91, 92, and 93 integrated into the discharge pipe 9 are connected to each chamber.

With the above configuration, the main suction pipe 1 for guiding the suction fluid
6 is connected to the first compressor 1, and in the middle of the main suction pipe 16, it is connected to the first suction branch pipe 26 connected to the second compressor 2 and the third compressor 3, as shown clearly in FIG. The second suction branch pipe 36 is branched, and the branch starting ends 26a, 36a of these suction branch pipes 26, 36 are located inwardly from the inner wall of the main suction pipe 16, and each The pressure loss of the suction branch pipes 26, 36 is increased, and the internal pressure of the casings 21, 31 in the second and third compressors 2, 3 is reduced almost equally with respect to the internal pressure of the casing 11 in the first compressor 1. The first compressor 1 is the main compressor 1 on the high pressure side, and the second and third compressors 2 and 3 are the slave compressors 2 and 3 on the low pressure side.
A forced differential pressure means 4 is provided which is divided into three sections.

Furthermore, as described above, the suction branch pipes 26, 3
By locating the branch starting ends 26a and 36a of 6 on the inner side of the inner wall of the main suction pipe 16, the oil that returns mainly along the inner wall of the main suction pipe 16 due to the wettability of the oil is removed from each suction pipe. It is made difficult to flow to the branch pipes 26 and 36 side, and a larger amount of oil is returned to the first compressor 1, which is the parent compressor on the high pressure side, than to the second and third compressors 2 and 3, which are the slave compressors on the low pressure side. This constitutes an oil return means 5.

Two oil equalizing pipe connection ports 81 and 82 are provided in the casing 11 of the first compressor 1, which is the parent compressor, to connect the first compressor 1 to the second and second compressors, which are the child compressors. Between the three compressors 2 and 3, first and second oil equalizing pipes 6 each open downward relative to the specified oil level of each oil reservoir 10, 20, 30.
, 7 are connected individually.

With the above configuration, one side (for example, the second compressor 2) of the second and third compressors 2 and 3, which are low-pressure side child compressors, where oil is not returned from the suction path is stopped. ,
Even if the internal pressure of the casing 21 reaches the highest pressure regardless of the differential pressure setting by the forced differential pressure means 4, the third compressor 3, which is another child compressor that continues to operate, is connected to the stop machine 2. The oil moves from the first compressor 1 via the first oil equalizing pipe 6 that has been routed and the second oil equalizing pipe 7 that has been routed separately, and the oil is transferred to both the first compressor 1 and the third compressor 3 that are in continuous operation. This allows the oil level to be maintained at an appropriate level.

Furthermore, even if the first compressor 1, which is the parent compressor, is stopped, the oil supply source side through the oil equalizing pipe will only have the highest pressure, so the second and third compressors 2 on the low pressure side , 3 without any trouble, and during full operation, oil can be transferred from the parent compressor 1 to each child compressor 2, 3 according to the differential pressure setting by the forced differential pressure means 4, and When only one of the two compressors is in operation and the main compressor 1 is stopped, oil can be transferred from the stopped main compressor 1 to the operating child compressor, and in addition, only the main compressor 1 is operating independently. When this is done, the oil is concentratedly returned to the parent compressor 1 by the oil return means 5, so that the oil level in the parent compressor 1 can be secured.

Therefore, it is possible to cope with any change in the number of operating compressors 1, 2, and 3, and it is possible to maintain an appropriate oil level in the operating compressors in each operating mode, and to maintain lubrication. This makes it possible to ensure good refueling.

Incidentally, the oil equalizing pipe connection ports 81 and 82 provided in the first compressor 1 serving as the parent compressor may be opened directly into the wall surface of the casing 11, but as shown in FIG. It is preferable to form a separate connection seat 8 having oil pipe connection ports 81, 82, 83, 84, and to attach this connection seat 8 to the casing 11 of the first compressor 1 serving as the parent compressor. In this case, the connection structure in the first compressor 1 to which the plurality of oil equalizing pipes 6 and 7 are connected can be simplified. Note that the unused connection ports 83 and 84 are covered.

[0020] In the embodiment described above, a triple type was shown, but it goes without saying that the present invention can be similarly applied to a compressor with a total number of four or more and three or more slave compressors. do not have.

[0021]

[Effects of the Invention] As described above, according to the present invention, three or more compressors 1, 2, and 3 can be satisfactorily operated in full operation and individually in three or more compressors 1, 2, and 3 without intervening a check mechanism in the oil equalizing pipe. Of course, the secondary compressor 2 on the low pressure side with a small amount of oil returned
, 3 is stopped, the main compressor 1 is connected to the other child compressors that are still in operation via an oil equalizing pipe that is connected separately from the oil equalizing pipe connected to the stopped machine. Oil can be moved, and three or more compressors can be connected in an oil-equalized manner with a simple structure.

When attaching the connection seat 8 having a plurality of oil equalizing pipe connection ports to the casing of the main compressor 1, the connection structure in the main compressor 1 to which the plural oil equalizing pipes 6 and 7 are connected can be simplified. It can be done.

[Brief explanation of the drawing]

FIG. 1 is a piping diagram showing the overall structure of a connected compression device according to the present invention.

FIG. 2 is a sectional view of a main part showing the structure of the forced differential pressure means and oil return means.

FIG. 3 is a perspective view showing the structure of a homogeneous oil pipe connection seat.

FIG. 4 is a piping diagram showing a conventional connected compression device.

[Explanation of symbols]

1 First compressor (main compressor) 2 Second compressor (child compressor) 3 Third compressor (child compressor) 4 Forced differential pressure means 5 Oil return means 6 First oil equalization pipe 7 Second oil equalization pipe 8 Connection seat

Claims (2)

[Claims] Claim 1: In a connected compression device comprising three or more compressors 1, 2, and 3 each having a compression element built into a casing having an oil reservoir, the internal pressure of the casing of one compressor 1 is The internal pressures of the casings in the compressors 2 and 3 are reduced almost equally, and one compressor is used as the high-pressure side main compressor 1 and the other compressors are used as the low-pressure side slave compressors 2 and 3. A forced differential pressure means 4 is provided, and an oil return means 5 is provided to return more oil to the parent compressor 1 than the child compressors 2 and 3, and a plurality of oil equalizing pipes are connected to the parent compressor 1. The main compressor 1 and each of the child compressors 2 and 3 are provided with ports.
A connected compression device characterized in that oil equalizing pipes 6 and 7 are individually connected between the two. 2. The connected compression device according to claim 1, further comprising a connecting seat 8 having a plurality of oil equalizing pipe connecting ports, and the connecting seat 8 being attached to the casing of the main compressor 1.