CN-122014619-A - Saturated steam dry gas sealing device and system of screw machine

CN122014619ACN 122014619 ACN122014619 ACN 122014619ACN-122014619-A

Abstract

A saturated steam dry gas sealing device and a system of a screw machine comprise a front seal, a dry gas seal, an isolation seal and a heat insulation sleeve. The shell of the screw machine is provided with a balance port at a position corresponding to the front seal, a superheated steam inlet is arranged at a gap position between the front seal and the dry gas seal, an exhaust port is arranged at a position corresponding to the dry gas seal, a hot nitrogen inlet is arranged at a position corresponding to the isolation seal, and a vent port is arranged at a position corresponding to the heat insulation sleeve. The sealing body of the invention has safe and stable operation, good sealing effect and long service life.

Inventors

ZHU YISHI
TIAN CHENGCHENG
SUN YUAN
Li Shaoang
WANG JUNJIE
Xu zitong
WANG ZHIGAO

Assignees

华东理工大学
上海齐耀节能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (14)

1. The saturated steam dry gas sealing device of the screw machine comprises a front seal, a dry gas seal and an isolation seal, wherein the front seal, the dry gas seal and the isolation seal are respectively arranged in a cavity between a rotor shaft of the screw machine and a shell of the screw machine, the dry gas seal is arranged between the front seal and the isolation seal, and the front seal is close to a working cavity of the screw machine; the shell of the screw machine is provided with a balance port at a position corresponding to the front seal, a superheated steam inlet at a position corresponding to a gap between the front seal and the dry gas seal, an exhaust port at a position corresponding to the dry gas seal, a hot nitrogen inlet at a position corresponding to the isolation seal, and an air vent at a position corresponding to the heat insulation sleeve; The side wall of the front seal is provided with a balance gas outlet communicated with the balance port, the side wall of the dry gas seal is provided with a seal gas outlet communicated with the exhaust port, the side wall of the isolation seal is provided with an isolation seal gas inlet communicated with the hot nitrogen inlet, and the side wall of the heat insulation sleeve is provided with an exhaust outlet communicated with the exhaust port.
2. The saturated vapor dry gas sealing device of a screw machine according to claim 1, wherein the balance gas outlet comprises a first annular groove and a plurality of first through holes, the first annular groove is formed in the outer side face of the front seal and extends along the circumferential direction of the front seal, the plurality of first through holes are distributed at intervals along the circumferential direction of the front seal, one end of each first through hole is opened at the bottom face of the first annular groove, and the other end of each first through hole penetrates through the inner wall of the front seal.
3. The saturated vapor dry gas sealing device of the screw machine according to claim 1, wherein the sealing gas outlet comprises a second annular groove and a plurality of second through holes, the second annular groove is formed in the outer side face of the dry gas seal and extends along the circumferential direction of the dry gas seal, the plurality of second through holes are distributed at intervals along the circumferential direction of the dry gas seal, one end of each second through hole is opened at the bottom face of the second annular groove, and the other end of each second through hole is communicated with the inside of the dry gas seal.
4. The saturated vapor dry gas sealing device of the screw machine according to claim 1, wherein the isolation seal gas inlet comprises a third annular groove and a plurality of third through holes, the third annular groove is formed in the outer side face of the isolation seal and extends along the circumferential direction of the isolation seal, the plurality of third through holes are distributed at intervals along the circumferential direction of the isolation seal, one end of each third through hole is opened at the bottom face of the third annular groove, and the other end of each third through hole penetrates through the inner wall of the isolation seal.
5. The saturated vapor dry gas sealing device of a screw machine of claim 1, wherein the vent outlet comprises a fourth annular groove and a plurality of fourth through holes, the fourth annular groove is formed in the outer side surface of the heat insulation sleeve and extends along the circumferential direction of the heat insulation sleeve, the plurality of fourth through holes are distributed at intervals along the circumferential direction of the heat insulation sleeve, one end of each fourth through hole is opened at the bottom surface of the fourth annular groove, and the other end of each fourth through hole penetrates through the inner wall of the heat insulation sleeve.
6. The saturated vapor dry gas sealing device of any one of claims 1 to 5, wherein the rotor shaft comprises a rotor shaft body and a shaft sleeve, and the shaft sleeve is sleeved outside the rotor shaft body and is connected with the dry gas sealed movable ring.
7. The saturated vapor dry gas seal device of a screw machine of claim 6, wherein the sleeve is integral with the dry gas seal and the isolation seal.
8. The saturated vapor dry gas sealing device of the screw machine according to claim 6, wherein the saturated vapor dry gas sealing device comprises a gland assembly which is sleeved outside a rotor shaft of the screw machine and is connected with the shell; The gland assembly is respectively abutted against the heat insulation sleeve and the shaft sleeve so as to limit the shaft sleeve and the heat insulation sleeve to axially move in the direction of approaching to the bearing cavity of the screw machine.
9. The saturated vapor dry gas seal device of the screw machine of claim 1, wherein the seal structure between the heat insulating sleeve and the outer peripheral surface of the rotor shaft is a comb tooth seal structure or a carbon ring seal structure.
10. The saturated vapor dry gas sealing device of the screw machine according to claim 1, wherein the front sealing is comb tooth sealing or carbon ring sealing, and the isolation sealing is comb tooth sealing, carbon ring sealing or dry gas sealing.
11. The saturated vapor dry gas seal device of a screw machine of claim 1, wherein the screw machine is a screw compressor or a screw expander.
12. A saturated vapour dry gas sealing system of a screw machine, the screw machine comprising a plurality of rotors, wherein rotor shafts on both sides of each rotor are provided with a saturated vapour dry gas sealing device according to any one of claims 1 to 10; the saturated steam dry gas sealing system comprises a balance pipeline, a steam inlet pipeline, an exhaust pipeline, a nitrogen pipeline, an emptying pipeline, a first pressure taking pipeline, a second pressure taking pipeline and a differential pressure transmitter; the number of the balance pipelines is the same as that of the rotors, and two ends of each balance pipeline are respectively communicated with balance ports of the saturated steam dry gas sealing devices on two sides of the corresponding rotors; The inlet end of the steam inlet pipeline is communicated with a vent port on the high pressure side of the screw machine, the outlet end of the steam inlet pipeline is communicated with the superheated steam inlet of each saturated steam dry gas sealing device, and the steam inlet pipeline is provided with a steam heater, a differential pressure regulating valve, a steam temperature transmitter and a steam pressure transmitter; the exhaust pipeline is communicated with the exhaust ports of the saturated steam dry gas sealing devices; the outlet end of the nitrogen pipeline is communicated with the hot nitrogen inlet of each saturated steam dry gas sealing device, and a nitrogen heater, a nitrogen temperature transmitter and a nitrogen pressure transmitter are arranged on the nitrogen pipeline; the emptying pipeline is communicated with the emptying port of each saturated steam dry gas sealing device; The first end of the first pressure taking pipeline is communicated with a pipe section of the vapor inlet pipeline, which is positioned at the downstream of the pressure difference regulating valve, and the second end of the first pressure taking pipeline is communicated with the first end of the pressure difference transmitter; The controller is used for receiving temperature measurement results of the vapor temperature transmitter and the nitrogen temperature transmitter, pressure measurement results of the vapor pressure transmitter and the nitrogen pressure transmitter, pressure difference measurement results of the pressure difference transmitter and valve states fed back by the pressure difference regulating valve, controlling heating power of the vapor heater and the nitrogen heater to enable overheat vapor output by an outlet end of the vapor inlet pipeline to have superheat degree of more than 20 ℃, and enabling the temperature of nitrogen output by an outlet end of the nitrogen pipeline to be higher than the saturation temperature of the discharge vapor of the exhaust port at the discharge pressure by more than 20 ℃, and controlling the opening degree of the pressure difference regulating valve according to the pressure difference measurement results to enable the pressure difference between a first end and a second end of the pressure difference transmitter to be larger than 0.
13. The saturated vapor dry gas seal system of claim 12, wherein the controller is configured to control the opening of the differential pressure regulator based on the differential pressure measurement such that the differential pressure between the first end and the second end of the differential pressure transmitter is maintained at 0.2MPa.
14. The saturated vapor dry gas seal system of claim 12, wherein the screw machine is a twin screw compressor, the vent on the low pressure side of the screw machine is an air inlet of the twin screw compressor, and the vent on the high pressure side of the screw machine is an air outlet of the twin screw compressor.

Description

Saturated steam dry gas sealing device and system of screw machine Technical Field The invention relates to the technical field of process equipment sealing, in particular to a sealing technology of a screw machine. Background Under the dual-carbon background of '3060', industrial energy conservation becomes an important field of carbon reduction, wherein the recycling of low-grade waste heat is one of important measures of industrial energy conservation, and relates to recycling of low-grade steam waste heat and the like. Because the low-temperature waste heat is generally low in temperature and pressure and difficult to utilize, the compressor can be adopted for boosting and heating, so that the waste heat can be reused. The vapor compressor in the energy-saving technology is core equipment, and vapor compressors suitable for various working conditions are developed in recent years in China, wherein the shaft seal performance is a key for influencing the safe and stable operation of the equipment. Because the saturated steam has high heat exchange efficiency, most of the outlet gas of the compressor is in a saturated state (gas-liquid coexisting state), and the saturated outlet gas brings certain difficulty for sealing and selecting types. Common shaft seals for compressors include carbon ring seals (or labyrinth seals), mechanical seals, and dry gas seals. When the discharge gas of the screw compressor is saturated gas (e.g., saturated water vapor), mechanical sealing and dry gas sealing of inert gas are not satisfactory to prevent external impurities such as lubricating oil from entering the system. The combined mode of the carbon ring sealing matched extraction condensing system can avoid external impurities from entering the system, but has the problems of large saturated gas leakage amount, high extraction power consumption, high condensed water consumption and the like. And when the carbocycle runs for a long time, abrasion is aggravated, saturation gas is extremely easy to enter a lubricating oil system, and poor lubrication and medium leakage of the bearing are caused. Conventional dry gas seals are non-contact seals with good sealing effect and long service life, but saturated gas with lower temperature will cause severe abrasion of the sealing surface to fail when passing through the sealing surface, and no effective solution exists in the market at present. Disclosure of Invention The invention aims to solve the technical problem of providing a saturated steam dry gas sealing device and a system of a screw machine, wherein a sealing body of the saturated steam dry gas sealing device is safe and stable in operation, good in sealing effect and long in service life, and cannot pollute working media in a working cavity of the screw machine. According to the first aspect of the invention, a saturated steam dry gas sealing device of a screw machine is provided, and comprises a front seal, a dry gas seal and an isolation seal, wherein the front seal, the dry gas seal and the isolation seal are respectively arranged in a cavity between a rotor shaft of the screw machine and a shell of the screw machine, the dry gas seal is arranged between the front seal and the isolation seal, the front seal is close to a working cavity of the screw machine, the saturated steam dry gas sealing device is characterized by further comprising a heat insulation sleeve, the heat insulation sleeve is arranged in the cavity between the rotor shaft of the screw machine and the shell and is positioned between the isolation seal and a bearing cavity of the screw machine, the heat insulation sleeve is sleeved outside the rotor shaft, a sealing structure is arranged between the heat insulation sleeve and the outer peripheral surface of the rotor shaft, a balance port is arranged on the shell of the screw machine at a position corresponding to the front seal, an air outlet is arranged at a position corresponding to the gap between the front seal and the dry gas seal, a hot nitrogen inlet is arranged at a position corresponding to the isolation seal, an air outlet is arranged at a position corresponding to the isolation seal, a side wall of the front seal is provided with a balance air outlet which is communicated with the heat insulation seal, and a side wall of the heat insulation seal is communicated with the balance air outlet, and the heat insulation outlet is arranged at the balance air outlet and the balance air outlet is communicated with the heat outlet. According to a second aspect of the present invention, there is provided a saturated vapor dry gas sealing system of a screw machine, the screw machine comprising a plurality of rotors, rotor shafts on both sides of each rotor being provided with the saturated vapor dry gas sealing device, the saturated vapor dry gas sealing system comprising a balance pipe, a vapor intake pipe, an exhaust pipe, a nitrogen pipe, an air release pipe, a first pressure taking pipe, a second pr