JPH10110831A - Sealing device for refregerating compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air from entering a system when a vacuum is drawn in the system when filling the system with refrigerant, in a refrigerating compressor sealing device provided with a labyrinth which has a labyrinth inside, in which a hole for supplying gas leaks purging gas is opened in the center in the axial direction of the labyrinth, at the end part on atmospheric side. SOLUTION: A rotating body-sleeve 6 having a flange part at the inside end, is provided on the rotary shaft 58 of a compressor, and a labyrinth member is made up of an outer peripheral fixing member 8 which is provided with a ring-like projected part 8a inside, and a labyrinth piston 1 which is provided with collars 2a, 2b habing the labyrinth inside and abutting on the inside end face of the ring-like projected part 8a to limit its movement to the inside end, provided with the collars 2a, 2b forming a closed chamber 5 between the outside end face of the ring-like projected part 8a and themselves, at the outside ende, and held slidably in the direction of the rotary shaft inside the outer peripheral fixing member 8. A compression spring 4 is provided in the closed chamber 5 in the direction of the rotary shaft. Further, a connecting hole for connecting the suction part of the compressor to the closed chamber 5 is provided in the outer peripheral fixing member 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shaft sealing device for a refrigerating compressor.

[0002]

2. Description of the Related Art FIG. 3 is a system diagram of a closed refrigeration cycle equipped with a conventional refrigeration compressor. In the figure, 51 is an evaporator, 52 is a refrigerating compressor, 53 is a condenser, 54 is an expansion valve,
55 is a refrigerant, 56 is brine, and 57 is a heat exchanger in a product manufacturing process.

In this system, the vapor of the refrigerant 55 generated from the evaporator 51 is compressed by the refrigerating compressor 52 to become high-pressure superheated vapor, and the liquid is deprived of heat by the cooling water in the condenser 53. When the high-pressure liquid is decompressed by the expansion valve 54, the temperature drops due to the throttle effect. This low-pressure and low-temperature refrigerant is supplied to the evaporator 5
When evaporating in step 1, the heat of evaporation is removed from the surroundings, and the vapor is returned to the compressor 52 as low-pressure steam. In some cases, the evaporator 51 directly cools the material, but in the illustrated system, the brine 56 having a low freezing point is used.
Is cooled and the brine is transferred to the heat exchanger 57 in the product manufacturing process.
The product is sent to the cooling process. In order to fill the refrigerant 55 in such a closed refrigeration cycle system, the interior of the system must be evacuated by a vacuum pump or the like to evacuate the system before the refrigerant enters the system. Impair.

FIG. 4 is a longitudinal sectional view of the refrigerating compressor 52. In the figure, 58 is a rotating shaft, 59 is a casing, 60
Is a shaft sealing device provided between the rotating shaft 58 and the casing 59. The refrigeration compressor is provided with symmetrical shaft sealing devices 60 at both ends of the rotating shaft. Refrigerant gas 55
Enters along a white arrow and is discharged along a black coloring arrow.

FIG. 5 is a longitudinal sectional view of the shaft sealing device 60 and shows a system of a sealing gas used for a seal during operation. FIG. 6 is an enlarged vertical sectional view of the shaft sealing device 60 on the right side of FIG. In the figure, 58 is a rotating shaft, 55 is a refrigerant gas for sealing, 21 is a filter connected to the refrigerant gas introduction pipe, 22 is a seal control valve provided on the refrigerant gas introduction pipe, and 23 is the refrigerant gas injected. Inside seal room, 2
Reference numeral 4 denotes an inboard space, 25 denotes a labyrinth member provided on the innermost side of the shaft sealing device, 31 denotes a labyrinth member located on the outermost side of the shaft sealing device, 26 denotes a dry seal, 27 denotes an outer seal chamber, and 28 denotes An orifice provided in a pipe connected to the outer seal chamber, 61 is a combustion field connected to the outer seal chamber 27, 62 is a nitrogen gas for purging leaked gas ejected to the center of the labyrinth 30, and 29 is connected to the gas source. A leak gas purge line 63 is a discharge gas line connected to the outside space 30.

The dry seal 26 is performed during operation by using the same gas as the gas in the machine. The inside space 24 inside the shaft seals on both sides (suction side, discharge side) of the compressor is balanced by the same pressure. The refrigerant gas 55 supplied to the primary seal is sent to the inside seal chamber 23 through the filter 21 and the seal control valve 22. Inside seal room 23
Is regulated by the seal control valve 22 at a pressure slightly higher than the inside of the machine 24. A part of the refrigerant gas entering the seal chamber 23 enters the inside of the machine from the labyrinth 25, and a part of the refrigerant gas exits to the outside seal chamber 27 through the shaft seal 26. During this process, the contact seal portion (64 in FIG. 6)
Is reduced when passing through, the refrigerant gas discharged to the outside seal chamber 27 is depressurized by the orifice 28 and sent to the combustion field 61 for combustion. Reference numeral 29 denotes a leakage gas purge line for a secondary seal, and an inert gas such as a nitrogen gas 62 is pressurized and supplied to prevent the refrigerant gas leaking to the outside seal chamber 27 from leaking outside the machine. And the released gas line 6 from the outside space 30 together with the leaked slight refrigerant gas.
It is released into the atmosphere via 3. Note that the leakage of the refrigerant gas to the outside space 30 is a slight amount because the pressure is reduced by the contact seal portion 65 on the way.

[0007]

In order to charge the refrigerant system to the refrigerant system before starting the refrigeration compressor, it is necessary to evacuate the entire refrigerant system including the refrigeration compressor using a vacuum pump or the like. However, when a refrigerating compressor equipped with a dry gas seal is employed, the inside of the refrigerant system cannot be filled with 100% refrigerant due to leakage of external air during evacuation.

The present invention is provided to solve this problem, and when charging the refrigerant to the refrigeration compressor to evacuate the inside of the refrigeration compressor, external air is sealed in the shaft sealing device. To prevent the air from entering the inside of the cooling medium, thereby preventing air from being mixed into the refrigerant to be charged.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and relates to a shaft sealing device for a refrigerating compressor having the following features.

(1) A labyrinth member having a dry seal inside, a labyrinth on an inner surface at an outer (atmospheric side) end thereof, and a supply hole for leakage gas purging gas opened at an axial center of the labyrinth. In the shaft sealing device for a refrigerating compressor, a rotating body sleeve having a flange portion at an inner end is provided on a rotating shaft of the compressor, and the labyrinth member is provided with an outer peripheral fixing member provided with an annular protrusion inside. A flange having an inner surface with a labyrinth and having an inner end with a flange abutting against the inner end surface of the annular protrusion to restrict movement, and a flange forming an airtight chamber between the outer end and the outer end surface of the annular protrusion. A labyrinth piston which is slidably held in the direction of the rotation axis inside the outer peripheral fixing member, and a compression spring in the direction of the rotation axis is provided in the closed chamber,
When the outer peripheral fixing member is provided with a communication hole communicating from the suction portion of the compressor to the closed chamber, when the inside of the compressor has a negative pressure,
The space between the flange of the rotating body sleeve and the flange at the inner end of the labyrinth piston is closed.

(2) In the shaft sealing device for a refrigerating compressor described in the above item (1), a non-contact type probe for detecting the position of the labyrinth piston is provided outside the labyrinth piston, and the signal is transmitted to the start interlock. Incorporation prevents the compressor from starting when the labyrinth piston is in the closed position.

The operation of the present invention is as follows. In a refrigerant system having a refrigerating compressor equipped with the shaft sealing device of the present invention,
When the system is evacuated to fill the refrigerant, the closed chamber becomes negative pressure, the volume of the closed chamber is minimized, the labyrinth piston moves inward of the compressor, and a flange at the inner end thereof is provided on the same flange. The air passage is closed by contacting the flange of the rotating body sleeve via an O-ring or the like. Therefore, since air does not enter from the labyrinth portion, sufficient evacuation can be performed, and entry of air into the refrigerant is prevented.

When the pressure of the compressor suction section becomes higher than the atmospheric pressure after the filling of the refrigerant, the labyrinth piston moves to the atmosphere side with the help of the compression spring, and opens the air passage between the rotating body sleeve and the shaft seal. Put the device in an operable state.

In the case where a non-contact type probe is provided, the probe confirms the position of the labyrinth piston,
Release the start interlock and complete the preparation for starting the compressor. This prevents the compressor from starting when the labyrinth piston is in the closed position.

[0015]

FIG. 1 is a partial longitudinal sectional view of a shaft sealing device for a refrigerating compressor according to an embodiment of the present invention. This shows the outermost part of the shaft sealing device, that is, a part on the atmosphere side. In the figure, 58 is a rotation axis, 30 is a space outside the machine,
29 is a leak gas purge line, 62 is a purge nitrogen gas, and 63 is a release gas line. The components described above have the same functions as those described in the section of the prior art. Reference numeral 6 denotes a rotating body sleeve mounted around the rotating shaft 58, 8 denotes an outer peripheral fixing member provided on the outer peripheral portion, 8a denotes an annular projecting portion inside the same member, and 1 denotes an inner peripheral fixing member 8 mounted. Is a labyrinth piston, which has been. 1a is a labyrinth fin provided on the inner circumference of the labyrinth piston, 2
a is a collar formed at the inner end of the labyrinth piston,
2b is a flange attached to the outer end of the labyrinth piston. The labyrinth piston 1 uses the end face of the annular protruding portion 8a as a stopper and the flanges 2a and 2b as its locking portions, in the axial direction of the rotation shaft 58 within a limited range inside the outer peripheral fixing member 8 (white in the figure). (In the direction of the pullout arrow). Reference numeral 3a denotes an O-ring provided on one end of the labyrinth piston 1 facing the flange portion of the rotating body sleeve 6, and 3b denotes an O-ring provided on the outer periphery of the flange 2b facing the inner surface of the outer peripheral fixing member 8. Reference numeral 5 denotes a closed chamber formed by being surrounded by the outer peripheral fixing member 8, the labyrinth piston 1 and the flange 2b, and 4 denotes a plurality of axially provided plural members provided between the end surface of the annular projection 8a and the end surface of the flange 2b. Compression spring, 9
Is a pipe communicating with the suction part of the compressor, and is connected to the closed chamber 5. Reference numeral 29a denotes a purging nitrogen gas injection hole connected to the leak gas purge line 29 and opened at the center of the labyrinth fin 1a via the outer peripheral fixing member 8 and the labyrinth piston 1. Reference numeral 7 denotes a non-contact type probe, the function of which will be described later.

In this apparatus, the labyrinth member 31 at the outermost end of the shaft sealing portion in the prior art (FIGS.
Into a movable labyrinth piston 1 and reconfigured,
A closed chamber 5 formed between the two parts is connected to a pipe 9 through a compressor suction part.
Are communicated with each other. The purging nitrogen gas injection hole provided through the member 31 in the prior art is provided through the members 8 and 1 in this apparatus (reference numeral 29a).

FIG. 2 is a diagram for explaining the operation of the shaft sealing device.
(A) shows the state before charging the refrigerant, and (b) shows the state before starting and operating the compressor. When the refrigerant system is evacuated when the labyrinth piston 1 is in an open state in order to fill the system having the refrigerating compressor equipped with the shaft sealing device of the present embodiment with the refrigerant, the compressor suction part pressure becomes lower than the atmospheric pressure. Since it is low and becomes about -700 mmAg, the shaft sealing device is in the state shown in FIG. 7A, the volume of the closed chamber 5 is reduced, the labyrinth piston 1 is moved, and the flange 2b is formed by the annular projection 8a of the outer peripheral fixing member. When approaching the end face, the other flange 2a comes into contact with the flange 6a of the rotating body sleeve 6 via the O-ring 3a, and the gas passage in this portion is closed. Therefore, even if the inside of the compressor becomes a negative pressure, air is not sucked from the shaft sealing portion, so that a necessary vacuum can be maintained in the system. When the refrigerant is injected into the vacuum state, the refrigerant can be filled with 100% refrigerant without air.

After the refrigerant injection is completed and before the compressor is started, the compressor suction pressure is about 12.5 ata, and during the operation, the compressor suction pressure is about 5 ata. Therefore, the shaft sealing device is in the state shown in FIG.
That is, the volume of the closed chamber 5 is increased, the labyrinth piston 1 moves, the flange 2a is separated from the flange portion 6a of the rotating body sleeve 6, the gas passage in this portion is opened, and operation becomes possible.

The probe 7 shown in FIG. 1 detects the open / closed state of the labyrinth piston 1 and incorporates this signal into a start interlock to prevent the start of the compressor in the closed state of the shaft seal device. When the start interlock is started in a state where the labyrinth piston 1 and the flange portion 6a of the rotating body sleeve are in contact (closed state), seizure occurs here. Therefore, a safety circuit that prevents the start switch from being turned on unless the open state is established. It is. Non-contact probe 7
However, when the movement of the labyrinth piston 1 to the gas passage open state is detected, the start interlock is released, and the start preparation is completed.

According to the shaft sealing device for a refrigerating compressor of the present invention, the refrigerating machine can be made to have a high vacuum, so that an efficient refrigerant system can be established. In addition, the refrigerant gas can be charged while maintaining a vacuum without leaking the expensive refrigerant gas.

[0021]

The shaft sealing device for a refrigerating compressor according to the present invention is provided with a labyrinth piston for opening and closing the air passage by an internal / external pressure difference. It is possible to prevent intrusion and prevent air from being mixed into the refrigerant. In the case where the non-contact type probe is provided, since the probe checks the position of the labyrinth piston, the start of the compressor when the labyrinth piston is at the closed position is prevented.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a shaft sealing device for a refrigerating compressor according to one embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the shaft sealing device.

FIG. 3 is a system diagram of a closed refrigeration cycle including a conventional refrigeration compressor.

FIG. 4 is a longitudinal sectional view of the refrigeration compressor.

FIG. 5 is a longitudinal sectional view of a shaft sealing device of the refrigerating compressor.

FIG. 6 is an enlarged vertical sectional view of the shaft sealing device of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Labyrinth piston 1a Labyrinth fin 2a, 2b Flange 3a, 3b O-ring 4 Compression spring 5 Sealed chamber 6 Rotating body sleeve 7 Probe 8 Outer peripheral fixing member 8a Annular protrusion of outer peripheral fixing member 9 Piping communicating with compressor suction part 21 Filter Reference Signs List 22 seal control valve 23 machine inner seal chamber 24 machine inner space 25 labyrinth member 26 dry seal 27 machine outer seal chamber 28 orifice 29 leak gas purge line 29a nitrogen gas supply hole for leak gas purge 30 machine outer space 31 labyrinth member 51 evaporator 52 refrigeration Compressor 53 Condenser 54 Expansion valve 55 Refrigerant 56 Brine 57 Heat exchanger 58 Rotating shaft 59 Casing 60 Shaft sealing device 61 Combustion field 62 Nitrogen gas 63 Release gas line (to atmosphere) 64 Contact seal 65 Contact seal

Claims (2)

[Claims] 1. A labyrinth member having a dry seal inside, a labyrinth on an inner surface at an outer (atmospheric side) end thereof, and a supply hole for leak gas purging gas opened at an axial center of the labyrinth. In the shaft sealing device for a refrigeration compressor, the rotating shaft of the compressor is provided with a rotating body sleeve having a flange portion at an inner end, and the labyrinth member is provided with an outer peripheral fixing member having an annular protrusion inside. ,
It has a labyrinth on the inner surface, a flange at the inner end that abuts against the inner end surface of the annular protrusion to limit the movement, and a flange at the outer end that forms a sealed chamber with the outer end surface of the annular protrusion. A labyrinth piston which is slidably held in the direction of the rotation axis inside the outer peripheral fixing member, and a compression spring in the direction of the rotational axis is provided in the closed chamber; A communication hole communicating from the suction portion to the closed chamber is provided so that when a negative pressure is generated in the compressor, the gap between the flange portion of the rotating body sleeve and the flange at the inner end of the labyrinth piston is closed. A shaft seal device for a refrigerating compressor. 2. The shaft sealing device for a refrigeration compressor according to claim 1, further comprising a non-contact type probe for detecting a position of the labyrinth piston outside the labyrinth piston, and incorporating a signal of the non-contact type probe into a start interlock, thereby providing a labyrinth. A shaft sealing device for a refrigerating compressor, wherein starting of a compressor when a piston is in a closed position is prevented.