Phase change sealing structure of negative pressure water vapor and negative pressure water vapor centrifugal compressor

Abstract

The utility model discloses a phase change sealing structure of negative pressure water vapor and a negative pressure water vapor centrifugal compressor, and solves the sealing problem of a negative pressure side and a normal pressure side in a water vapor host. And heat generated by the rotor cannot be discharged in time due to low density of negative pressure water vapor, and the bearing capacity of the air bearing to the rotor is insufficient. The utility model provides a phase change sealing structure of negative pressure steam. The phase change sealing structure comprises a water passing cover plate, a phase change labyrinth sealing piece and a heating plate. Small water through holes are formed in the water through cover plate in the radial direction, and liquid water flows in along the small water through holes and enters a gap between the water through cover plate and the main shaft through the one-way valve; a heating element in the heating plate emits heat and enables the temperature of the phase change labyrinth sealing piece to rise, the heating plate heats the temperature of the phase change labyrinth sealing piece to be higher than the saturation temperature of the negative pressure steam side, liquid water flowing through the labyrinth sealing area is rapidly evaporated, and the heating temperature of the heating plate on the phase change labyrinth sealing piece is adjustable. Therefore, the sealing effect is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of dynamic sealing device structures, and relates to a phase change sealing structure of negative pressure water vapor and a negative pressure water vapor centrifugal compressor. Background Art

[0002] With the rapid development of refrigeration, air conditioning and cryogenic industries in recent years, the annual demand for refrigerants in the world has reached millions of tons. Synthetic refrigerants such as chlorofluorocarbons will gradually withdraw from the stage of history because of their damage to the ozone layer and their promotion of the greenhouse effect. Therefore, finding new, efficient, green, environmentally friendly and easily available refrigerants has become a consensus in the entire refrigeration field. As one of the most easily available refrigerants in nature, water is green, environmentally friendly, cheap, stable, has no greenhouse effect, does not damage the ozone layer, and has a large latent heat of vaporization. It can be said to be the most ideal refrigerant. The most promising application of water and water vapor as refrigerants is the air conditioning system. Water refrigerants can use a compressed vapor refrigeration cycle in the air conditioning system to give full play to the advantage of its large latent heat of vaporization. Under typical summer household air conditioning conditions, the performance coefficient of water vapor refrigerants can reach more than 4, close to or even exceeding R22, R410A and other currently commonly used air conditioning refrigerants.

[0003] Under typical summer air conditioning conditions, the evaporation pressure of water vapor refrigerant is 1-2kPa, and the condensation pressure is 10-15kPa. Compared with other refrigerants used in air conditioning systems, the working pressure of water vapor is relatively small, and the entire working process is under a negative pressure state with a high vacuum degree. For negative pressure systems, since the absolute pressure and density of the working fluid in the system are both low, a small amount of external gas leaking into the system will cause a large increase in system pressure, so it is extremely important to do a good job of sealing the water vapor system.

[0004] Most existing negative pressure refrigeration systems, especially negative pressure water vapor refrigeration systems, adopt a complete closed cycle. The main engine, condenser, throttling device and evaporator are connected in sequence and use vacuum connectors that meet national standards. However, for negative pressure water vapor centrifugal compressors, it is necessary to solve the lubrication and support problems of the rotor system at high speeds. The air-floating bearings lubricated by working fluids have an extremely low density of water vapor refrigerant at its working pressure, and the air film provides insufficient bearing capacity; grease-lubricated bearings generate a lot of heat when running at high speeds, and it is difficult to discharge the heat in a low-density environment, and it is also difficult to use for a long time. Therefore, it is considered to place the contact surface between the rotor and the bearing in the atmosphere. The air-floating bearings in normal pressure air have an increased bearing capacity due to the increased air film density when the rotor is running. The ball bearings in normal pressure air also have a good heat dissipation environment when working. Therefore, the support and lubrication problems of the rotor system can be solved by properly sealing the atmosphere and the negative pressure system. Summary of the invention

[0005] In view of this, the utility model provides a phase change sealing structure for negative pressure water vapor, which is suitable for high-speed rotating machinery such as water vapor centrifugal compressors, and solves the sealing problems between the negative pressure side and the normal pressure side inside the water vapor main engine, as well as the problems of the heat generated by the rotor being unable to be discharged in time due to the low density of negative pressure water vapor and the insufficient bearing capacity of the air bearing on the rotor.

[0006] In order to solve the above problems, the embodiment of the utility model provides a negative pressure water vapor phase change sealing structure, which is special in that:

[0007] It includes a water-through cover plate, a phase-change labyrinth seal and a heating plate;

[0008] The water-through cover plate and the phase-change labyrinth seal are sequentially installed in the axial direction, the water-through cover plate is close to the normal-pressure air side, the phase-change labyrinth seal is close to the negative-pressure water vapor side, and the heating plate is arranged outside the phase-change labyrinth seal and in contact with the phase-change labyrinth seal;

[0009] The water-passing cover plate is provided with water-passing holes in the radial direction; the water-passing holes are opened from the radially outermost side to the radially innermost side of the water-passing cover plate, and when working, liquid water in the water vapor system is injected along the outer side of the water-passing holes, and the liquid water flows in along the water-passing holes, passes through the one-way valve, and enters the gap between the water-passing cover plate and the main shaft;

[0010] The heating plate has a heating element inside, and the heating element inside the heating plate generates heat and increases the temperature of the phase change labyrinth seal;

[0011] The heating plate heats the temperature of the phase change labyrinth seal to a temperature higher than the saturation temperature of the negative pressure water vapor side, so that the liquid water flowing through the labyrinth sealing area can be evaporated quickly, and the heating temperature of the phase change labyrinth seal by the heating plate is adjustable, thereby ensuring the sealing effect.

[0012] In some embodiments, the phase-change labyrinth seal has a labyrinth sealing structure disposed on its inner surface; the labyrinth sealing structure can be disposed on the phase-change labyrinth seal or on the main shaft.

[0013] In some embodiments, a water storage tank is provided on the uppermost side of the phase change labyrinth seal. Liquid water flowing into the water holes flows downward along the gap between the sealing structure and the main axis under the suction effect caused by the pressure difference between the normal pressure air side and the negative pressure water vapor side and the action of gravity. When the liquid water flows to the phase change labyrinth seal, the water storage tank provides water storage capacity, and works together with the backflowing water vapor to ensure that negative pressure air does not enter the labyrinth sealing area.

[0014] In some embodiments, an O-ring is provided on the contact surface between the phase change labyrinth seal and the water flow cover plate to prevent leakage from occurring on the contact surface between the phase change labyrinth seal and the water flow cover plate.

[0015] In some embodiments, a circle of pressure equalizing grooves is opened at the outlet of the water holes on the water-passing cover plate. When liquid water flows in along the water holes, the pressure equalizing grooves evenly distribute the liquid water in the gap between the water-passing cover plate and the main shaft, so that the liquid water fills the gap.

[0016] In addition, the present invention also proposes a negative pressure water vapor centrifugal compressor, which is special in that it includes the above-mentioned negative pressure water vapor phase change sealing structure.

[0017] Compared with the prior art, the phase change sealing structure of negative pressure water vapor of the utility model has at least the following beneficial effects:

[0018] 1. The phase change sealing structure of negative pressure water vapor provided by the utility model introduces liquid water in the water vapor system into the gap between the water-passing cover plate and the main shaft along the water-passing holes of the water-passing cover plate, and the gap between the water-passing cover plate and the main shaft is filled with liquid water, that is, the leakage surface between the negative pressure water vapor side and the normal pressure air side is filled with liquid water. Under the pressure difference between the normal pressure air side and the negative pressure water vapor side and the action of gravity, the liquid water flows downward along the gap into the water storage tank, and then enters the labyrinth sealing area in the gap between the phase change labyrinth seal and the main shaft. The heating components inside the heating plate generate heat and increase the temperature of the phase change labyrinth seal. The liquid water in the labyrinth sealing area evaporates rapidly and expands rapidly, resulting in a large amount of liquid in the labyrinth. A throttling effect and a stagnation effect are generated in the seal, and a very small amount of evaporated water vapor enters the negative pressure water vapor side. The liquid water flowing into the water-passing holes cannot further enter the labyrinth seal. The liquid water that has not yet flowed into the labyrinth seal area fills the gap between the water-passing cover plate and the main shaft. After the liquid water flowing into the water-passing holes fills the gap between the water-passing cover plate and the main shaft, it can flow out to the normal pressure air side without affecting the normal operation of the negative pressure water vapor side. The air on the normal pressure air side cannot enter the sealing side, forming a phase change sealing structure in which the evaporated water vapor seals the negative pressure water vapor side and the liquid water seals the normal pressure air side. Compared with the mechanical structure seal or the simple dry gas seal, the effect is better.

[0019] 2. The phase change sealing structure of negative pressure water vapor provided by the utility model, when liquid water passes into the gap between the water-passing cover plate and the main shaft, the liquid water will flow to the negative pressure water vapor side. Since the phase change labyrinth seal is heated by the heating plate and the saturation temperature of water vapor is low under negative pressure conditions, the liquid water will vaporize when flowing through the phase change labyrinth seal. The gap between the labyrinth seal structure and the main shaft is very small, and the volume of vaporized water vapor expands rapidly. In the process of flowing to the negative pressure water vapor side, it is affected by the throttling effect. The water vapor cannot flow to the negative pressure water vapor side through the gap of the labyrinth seal, thereby achieving a sealing effect between the negative pressure water vapor side and the normal pressure air side.

[0020] 3. The phase change sealing structure of negative pressure water vapor provided by the utility model can well seal the negative pressure water vapor and normal pressure air to prevent normal pressure air from entering the negative pressure system; when the negative pressure water vapor main unit is running, problems such as excessive heating of the motor and ball bearings and insufficient bearing capacity of the air bearings may occur due to the low density of the negative pressure water vapor. Therefore, it is necessary to place the bearings and the motor in a normal pressure air environment. The phase change sealing structure of negative pressure water vapor provided by the utility model proposes a method for solving such engineering problems.

[0021] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A cross-sectional schematic diagram of a phase change sealing structure of negative pressure water vapor provided by the utility model;

[0024] Figure 2 is an enlarged view of the sealing side structure;

[0025] Among them, 1. Sealing side, 2. Negative pressure water vapor side, 3. Normal pressure air side, 4. Water cover plate, 5. Phase change labyrinth seal, 6. Heating plate, 7. O-ring, 8. Water hole, 9. One-way valve, 10. Pressure equalizing tank, 11. Water storage tank, 12. Heating components. DETAILED DESCRIPTION

[0026] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0027] See also Figure 1-2 The utility model provides a phase change sealing structure of negative pressure water vapor, comprising a water-passing cover plate 4, a phase change labyrinth seal 5 and a heating plate 6.

[0028] Specifically, the water-passing cover plate 4 and the phase-change labyrinth seal 5 are installed in sequence in the axial direction, the water-passing cover plate 4 is close to the normal pressure air side 3, the phase-change labyrinth seal 5 is close to the negative pressure water vapor side 2, and the heating plate 6 is arranged outside the phase-change labyrinth seal 5 and contacts the phase-change labyrinth seal 5. The water-passing cover plate 4 is radially provided with water-passing holes 8; the water-passing holes 8 are opened from the radial outermost side to the radial innermost side of the water-passing cover plate 4, and during operation, liquid water in the water vapor system is injected along the outer side of the water-passing holes 8, and the liquid water flows in along the water-passing holes 8, passes through the one-way valve 9 and enters the gap between the water-passing cover plate 4 and the main shaft. The heating plate 6 has a heating element 12 inside, and the heating element 12 inside the heating plate 6 generates heat and increases the temperature of the phase-change labyrinth seal 5 to heat the heating element 12. The heating plate 6 heats the temperature of the phase change labyrinth seal 5 to a temperature higher than the saturation temperature of the negative pressure water vapor side, so that the liquid water flowing through the labyrinth sealing area can be evaporated quickly, and the heating temperature of the phase change labyrinth seal 5 by the heating plate 6 is adjustable, thereby ensuring the sealing effect.

[0029] Specifically, see Figure 2 The one-way valve 9 opens or closes the valve port by compressing and stretching the spring, allowing liquid water to flow into the water-passing hole 8 in one direction and preventing liquid water from flowing out of the water-passing hole 8 in the opposite direction. The amount of water inlet can be adjusted by adjusting the spring and the aperture.

[0030] As a preferred embodiment of the present utility model, the phase-change labyrinth seal 5 is provided with a labyrinth sealing structure on its inner surface; the labyrinth sealing structure can be provided on the phase-change labyrinth seal 5 or on the main shaft.

[0031] In some embodiments, a water storage tank 11 is provided at the top of the phase change labyrinth seal 5. Liquid water flowing into the water-passing hole 8 flows downward along the gap between the sealing structure and the main axis under the suction effect caused by the pressure difference between the normal pressure air side 3 and the negative pressure water vapor side 2 and the action of gravity. When the liquid water flows to the phase change labyrinth seal 5, the water storage tank 11 provides water storage capacity, and works together with the backflowing water vapor to ensure that the negative pressure air does not enter the labyrinth sealing area.

[0032] Liquid water flows into the gap between the water-passing cover plate 4 and the main shaft along the water-passing holes 8. Under the pressure difference between the normal-pressure air side and the negative-pressure water vapor side and the action of gravity, the liquid water flows downward along the gap into the water storage tank 11, and then enters the labyrinth sealing area in the gap between the phase-change labyrinth seal 5 and the main shaft. The heating components 12 inside the heating plate 6 generate heat and increase the temperature of the phase-change labyrinth seal 5. The liquid water in the labyrinth sealing area evaporates rapidly and expands rapidly, resulting in throttling effect and stagnation effect in the labyrinth seal. A very small amount of evaporated water vapor enters the negative-pressure water vapor side 2, and the rest of the water vapor flows back. The liquid water flows through the sealed labyrinth area and the water-passing holes 8 and is discharged. The liquid water flowing into the water-passing holes 8 cannot further enter the labyrinth seal. The liquid water that has not yet flowed into the labyrinth seal area fills the gap between the water-passing cover plate 4 and the main shaft. After the liquid water flowing into the water-passing holes 8 fills the gap between the water-passing cover plate 4 and the main shaft, it can flow out to the normal-pressure air side 3 without affecting the normal operation of the negative-pressure water vapor side 2. The air on the normal-pressure air side 3 cannot enter the sealing side 1, forming a phase change sealing structure in which the evaporated water vapor seals the negative-pressure water vapor side 2 and the liquid water seals the normal-pressure air side 3.

[0033] Furthermore, the heating plate 6 heats the temperature of the phase change labyrinth seal 5 to above the saturation temperature of water vapor under the pressure of the labyrinth seal, so that the liquid water flowing through the labyrinth seal area can be evaporated quickly, and the heating temperature of the phase change labyrinth seal 5 by the heating plate 6 is adjustable.

[0034] In some embodiments, an O-ring 7 is provided on the contact surface between the phase change labyrinth seal 5 and the water flow cover plate 4 to prevent leakage from occurring on the contact surface between the phase change labyrinth seal 5 and the water flow cover plate 4 .

[0035] In some embodiments, a circle of pressure equalizing grooves 10 are opened at the outlet of the water-passing holes 8 on the water-passing cover plate 4. When liquid water flows in along the water-passing holes 8, the pressure equalizing grooves 10 evenly distribute the liquid water in the gap between the water-passing cover plate 4 and the main shaft, so that the liquid water fills the gap.

[0036] In addition, the utility model also proposes a negative pressure water vapor centrifugal compressor, including the above-mentioned negative pressure water vapor phase change sealing structure. Because it includes the above-mentioned negative pressure water vapor phase change sealing structure, it also achieves the sealing effect of the above-mentioned negative pressure water vapor phase change sealing structure, which will not be repeated here.

[0037] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous technical features can be freely combined and superimposed.

[0038] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A negative pressure water vapor phase change sealing structure, characterized in that: It comprises a water-permeable cover plate (4), a phase-change labyrinth seal (5) and a heating plate (6); The water-passing cover plate (4) and the phase-change labyrinth seal (5) are sequentially installed in the axial direction, the water-passing cover plate (4) is close to the normal-pressure air side (3), the phase-change labyrinth seal (5) is close to the negative-pressure water vapor side (2), and the heating plate (6) is arranged outside the phase-change labyrinth seal (5) and in contact with the phase-change labyrinth seal (5); The water-passing cover plate (4) is provided with water-passing holes (8) in the radial direction; the water-passing holes (8) are opened from the radially outermost side to the radially innermost side of the water-passing cover plate (4); during operation, liquid water in the water vapor system is injected along the outer side of the water-passing holes (8), and the liquid water flows along the water-passing holes (8), passes through the one-way valve (9), and enters the gap between the water-passing cover plate (4) and the main shaft; The heating plate (6) has a heating element (12) inside, and the heating element (12) inside the heating plate (6) generates heat and increases the temperature of the phase change labyrinth seal (5). The heating plate (6) heats the temperature of the phase-change labyrinth seal (5) to a temperature higher than the saturation temperature of the negative pressure water vapor side, so that liquid water flowing through the labyrinth seal area can be rapidly evaporated, and the heating temperature of the phase-change labyrinth seal (5) by the heating plate (6) is adjustable, thereby ensuring the sealing effect.

2. The negative pressure water vapor phase change sealing structure according to claim 1, characterized in that: The phase-change labyrinth seal (5) has a labyrinth seal structure arranged on its inner surface; the labyrinth seal structure is arranged on the phase-change labyrinth seal (5) or on the main shaft.

3. The negative pressure water vapor phase change sealing structure according to claim 2, characterized in that: The phase-change labyrinth seal (5) is provided with a water storage tank (11) at the uppermost side. Liquid water flowing into the water-passing holes (8) flows downward along the gap between the sealing structure and the main shaft under the suction effect caused by the pressure difference between the normal-pressure air side (3) and the negative-pressure water vapor side (2) and the action of gravity. When the liquid water flows to the phase-change labyrinth seal (5), the water storage tank (11) provides water storage capacity and works together with the backflowing water vapor to ensure that the negative-pressure air does not enter the labyrinth sealing area.

4. The negative pressure water vapor phase change sealing structure according to claim 3, characterized in that: An O-ring (7) is provided on the contact surface between the phase-change labyrinth seal (5) and the water-passing cover plate (4) to prevent leakage from occurring on the contact surface between the phase-change labyrinth seal (5) and the water-passing cover plate (4).

5. A negative pressure water vapor phase change sealing structure according to any one of claims 1 to 4, characterized in that: A circle of equalizing grooves (10) is provided at the outlet of the water-passing small holes (8) on the water-passing cover plate (4). When liquid water flows in through the water-passing small holes (8), the equalizing grooves (10) evenly distribute the liquid water in the gap between the water-passing cover plate (4) and the main shaft, so that the liquid water fills the gap.

6. A negative pressure water vapor centrifugal compressor, characterized in that: A phase change sealing structure for negative pressure water vapor comprising any one of claims 1-5.

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