Non-contact shaft seal structure of dry vacuum pump

Abstract

The utility model relates to the field of sealing, in particular to a non-contact type shaft seal structure of a dry vacuum pump, a shaft seal located between a medium end and a motor end is arranged on a main shaft of the vacuum pump, an air seal ring is installed on the shaft seal, and a medium cavity of the medium end and a lubricating oil cavity of the motor end are separated through the air seal ring. The air source is communicated with the air sealing ring through the sealing channel; the pressure intensity in the air sealing ring is greater than the pressure intensity of the medium cavity of the medium end and the lubricating oil cavity of the motor end; the sealing structure in the vacuum pump is prevented from being abraded and losing efficacy, and the stability of the vacuum pump in the operation process is effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a sealed field, concretely is a kind of dry vacuum pump non-contact type shaft seal structure. BACKGROUND

[0002] Dry vacuum pump, namely oil-free dry mechanical vacuum pump, is simply called dry pump, and it is a kind of vacuum pump without using lubricating oil or sealing oil, which creates a low-pressure environment by mechanically removing air from the gas system. Dry vacuum pump is based on mechanical method to discharge gas. In the pump cavity, a series of mechanical structures (such as screw, scroll, piston or claw, etc.) are moved to suck gas from the air inlet, then compress and discharge to the air outlet. Since there is no lubricating oil in the pump cavity, the pollution of oil vapor to the vacuum environment can be avoided.

[0003] Since dry vacuum pump is often used in various clean and oil-free process, it requires no oil in the pump cavity during operation, and the shaft seal structure of the rotor needs to ensure that the lubricating oil in the motor end does not enter the pump cavity. To achieve the sealing of the motor end and the medium end, the conventional dry vacuum pump as described in the announcement number "CN217401152U" forms a mechanical seal by cooperating the dynamic ring and the static ring. This traditional mechanical seal form has direct contact and friction between the inside of the seal structure or the sealing ring and the shaft. After long-term work, the seal is easy to wear and fail. The temperature rise generated during the operation of the vacuum pump also easily causes the seal structure to wear and fail, so it needs to be solved urgently. CONTENT OF THE UTILITY MODEL

[0004] In order to avoid and overcome the technical problems existing in the prior art, the utility model provides a dry vacuum pump non-contact type shaft seal structure. The utility model avoids the wear and failure of the sealing structure in the vacuum pump, and effectively improves the stability of the vacuum pump during operation.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0006] A dry vacuum pump non-contact type shaft seal structure is provided, the main shaft of the vacuum pump is provided with a shaft seal between the medium end and the motor end, the shaft seal is installed with a gas seal ring, and the medium cavity of the medium end and the lubricating oil cavity of the motor end are separated by the gas seal ring. The gas source is communicated with the gas seal ring through the sealing channel, and the pressure in the gas seal ring is greater than the pressure in the medium cavity of the medium end and the lubricating oil cavity of the motor end.

[0007] As a further scheme of the utility model, a first three-way joint is installed on the pump body of the vacuum pump, the outlet of the first three-way joint is communicated with the sealing channel, and the two groups of inlets of the first three-way joint are opened alternatively, wherein the first inlet is communicated with the gas source, and the second inlet is communicated with the storage box. The storage box is configured to inject glue into the gas seal ring to block the communication between the medium cavity and the lubricating oil cavity when the vacuum pump leaks and stops.

[0008] As a further scheme of the utility model: the box cavity of the glue storage box is slidably provided with a thorn disc, the thorn disc divides the box cavity of the glue storage box into an air inlet cavity and a glue storage cavity, a glue storage bag is arranged in the glue storage cavity, and the thorn disc is driven to move towards the glue storage cavity after air injection in the air inlet cavity to exert a piercing action on the glue storage bag; the glue storage cavity is communicated with the second inlet of the first three-way joint through a glue injection pipe.

[0009] As a further scheme of the utility model: the air source is communicated with the inlet of the second three-way joint, and two groups of outlets of the second three-way joint are selectively opened; one group of outlets is communicated with the first inlet of the first three-way joint through an air inlet pipe, and the other group of outlets is communicated with the air inlet cavity through an emergency pipe.

[0010] As a further scheme of the utility model: the bag body of the glue storage bag stores cyanoacrylate quick-drying glue.

[0011] As a further scheme of the utility model: a pressure sensor is installed on the vacuum pump to monitor the pressure in the gas seal ring.

[0012] As a further scheme of the utility model: the medium end and the motor end are connected through a sealing seat, the shaft seal is arranged at the shaft center of the sealing seat, the sealing channel is arranged radially along the sealing seat, and a labyrinth seal is further installed between the shaft seal and the lubricating oil cavity of the motor end.

[0013] Compared with the prior art, the utility model has the advantages that:

[0014] 1. The shaft seal of the utility model does not directly contact the friction component, the positive pressure gas is introduced into the gas seal ring, the motor end and the medium end are prevented from being communicated under the action of the pressure difference, the pump cavity can be kept clean and oil-free during the operation of the vacuum pump, the problem of wear and failure of the traditional mechanical seal after long-term work is avoided, and the stability during the operation of the vacuum pump is effectively improved.

[0015] 2. The flow controller is installed on the air inlet pipe, the pressure sensor for monitoring the pressure in the gas seal ring is installed on the vacuum pump, the air inlet flow is adjusted in real time according to the pressure signal transmitted by the pressure sensor to keep the pressure in the gas seal ring constant.

[0016] 3. When the pressure of the vacuum pump is unbalanced and the air injection into the gas seal ring cannot achieve the sealing effect, the vacuum pump is stopped urgently, the air source stops injecting air into the sealing channel, and air is injected into the air inlet cavity of the glue storage box through the emergency pipe, the thorn disc is pushed to slide to one side of the glue storage cavity under the action of the pressure, the glue storage bag is pierced, the glue liquid in the glue storage bag enters the gas seal ring through the glue injection pipe and the sealing channel, the communication channel between the lubricating oil cavity and the medium cavity is completely blocked, the emergency sealing effect is achieved, the medium is prevented from entering the motor end to damage the motor, and the lubricating oil is prevented from entering the medium cavity to pollute the medium.

[0017] 4、 The utility model discloses simple and reliable, application cost is low, and does not depend on contact type seal, and basically has no abrasion failure possibility, long service life, and practicality is strong. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the structural schematic diagram of the utility model.

[0019] In the drawing:

[0020] 1, medium end; 2, motor end; 3, sealing seat; 4, main shaft;

[0021] 5, shaft seal; 51, sealing channel; 52, labyrinth seal;

[0022] 6, first tee joint; 61, air inlet pipe; 62, glue injection pipe;

[0023] 7, gas source; 71, second tee joint; 72, emergency pipe;

[0024] 8, glue storage box; 81, air inlet cavity; 82, glue storage cavity; 83, thorn disc; 84, glue storage capsule bag;

[0025] 9, pressure sensor. DETAILED DESCRIPTION

[0026] The technical scheme in the embodiments of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiments of the utility model, and obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the protection scope of the utility model.

[0027] Please refer to Figure 1 In the embodiments of the utility model, a dry vacuum pump non-contact type shaft seal structure, one end of the main shaft 4 of the vacuum pump is located in the motor end 2, the other end is located in the medium end 1, the motor end 2 and the medium end 1 of the vacuum pump are connected through the sealing seat 3, the shaft seal 5 is coaxially arranged in the sealing seat 3, the annular groove is coaxially set up on the shaft seal 5, the annular groove and the sealing seat 3 are enclosed to form the gas seal ring, the outer ring of the shaft seal 5 is also provided with the annular groove, and the ring cavity of the gas seal ring is communicated with the lubricating oil cavity in the motor end 2 and the medium cavity in the medium end 1 through the annular groove on the shaft seal 5. The labyrinth seal 52 is also installed between the shaft seal 5 and the lubricating oil cavity of the motor end 2.

[0028] A sealing channel 51 is provided radially on the sealing seat 3. The annular cavity of the air seal ring is connected to the outlet of the first three-way connector 6 through the sealing channel 51. The first three-way connector 6 has two inlets that can be opened selectively. The first inlet is connected to the air inlet pipe 61, and the second inlet is connected to the glue injection pipe 62. The glue injection pipe 62 and the air inlet pipe 61 are used to inject air or glue into the sealing channel 51, respectively.

[0029] The outlet of the gas source 7 is connected to the inlet of the second three-way connector 71. The second three-way connector 71 has two sets of outlets, one of which can be opened. The first outlet of the second three-way connector 71 is connected to the first three-way connector 6 through the air inlet pipe 61, and the second outlet of the second three-way connector 71 is connected to the glue storage box 8 through the emergency pipe 72.

[0030] A spiked disc 83 is slidably disposed inside the glue storage box 8, dividing the box cavity into an air inlet chamber 81 and a glue storage chamber 82. The air inlet chamber 81 is connected to the emergency pipe 72. A storage capsule bag 84 is disposed inside the glue storage chamber 82. The storage capsule bag 84 is a sealed bag containing cyanoacrylate quick-drying glue. The spiked disc 83 has spikes on the side facing the glue storage chamber 82. In the non-operating state, there is a gap between the spiked disc 83 and the storage capsule bag 84.

[0031] When the vacuum pump is working normally, the gas source 7 injects gas into the ring cavity of the gas seal ring through the second three-way connector 71, the air inlet pipe 61, the first three-way connector 6, and the sealing channel 51. The pressure inside the gas seal ring is greater than the pressure in the lubricating oil cavity in the motor end 2 and the medium cavity in the medium end 1. A flow controller is installed on the air inlet pipe 61, and a pressure sensor 9 is installed on the vacuum pump to monitor the pressure inside the gas seal ring. The air inlet flow rate is adjusted in real time according to the pressure signal transmitted by the pressure sensor 9 to maintain a constant pressure inside the gas seal ring.

[0032] When the vacuum pump pressure becomes unbalanced and injecting air into the gas sealing ring fails to achieve a sealing effect, the vacuum pump shuts down in an emergency. At this time, the air source 7 stops injecting air into the sealing channel 51 and instead injects air into the air inlet chamber 81 of the glue storage box 8 through the emergency pipe 72. Under pressure, the spiked disc 83 slides to one side of the glue storage chamber 82 and punctures the storage capsule bag 84, allowing the glue in the storage capsule bag 84 to enter the gas sealing ring through the glue injection pipe 62 and the sealing channel 51. This completely seals the connecting channel between the lubricating oil chamber and the medium chamber, achieving an emergency sealing effect. This prevents the medium from entering the motor end 2 and damaging the motor, and also prevents the lubricating oil from entering the medium chamber and contaminating the medium.

[0033] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0034] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

Claims

1. A contactless shaft seal structure for a dry vacuum pump, characterized in that, A shaft seal (5) is provided on the main shaft (4) of the vacuum pump between the medium end (1) and the motor end (2). An air seal ring is installed on the shaft seal (5). The medium cavity of the medium end (1) and the lubricating oil cavity of the motor end (2) are separated by the air seal ring. The air source (7) is connected to the air seal ring through the sealing channel (51). The pressure inside the air seal ring is greater than the pressure of the medium cavity of the medium end (1) and the lubricating oil cavity of the motor end (2).

2. The contactless shaft seal structure for a dry vacuum pump according to claim 1, characterized in that, The vacuum pump body is equipped with a first three-way connector (6). The outlet of the first three-way connector (6) is connected to the sealing channel (51). One of the two sets of inlets of the first three-way connector (6) can be opened. The first inlet is connected to the gas source (7), and the second inlet is connected to the glue storage box (8). The glue storage box (8) is configured to inject glue into the gas seal ring after the vacuum pump stops due to leakage to block the connection between the medium chamber and the lubricating oil chamber.

3. The contactless shaft seal structure for a dry vacuum pump according to claim 2, characterized in that, The storage box (8) has a slidably arranged spiked disc (83) inside its cavity. The spiked disc (83) divides the cavity of the storage box (8) into an air inlet cavity (81) and a storage cavity (82). The storage cavity (82) is provided with a storage capsule bag (84). After air is injected into the air inlet cavity (81), it drives the spiked disc (83) to move towards the storage cavity (82) to apply a piercing action to the storage capsule bag (84). The storage cavity (82) is connected to the second inlet of the first three-way connector (6) through the glue injection tube (62).

4. The contactless shaft seal structure for a dry vacuum pump according to claim 3, characterized in that, The gas source (7) is connected to the inlet of the second three-way connector (71). One of the two sets of outlets of the second three-way connector (71) is opened. One set of outlets is connected to the first inlet of the first three-way connector (6) through the air inlet pipe (61), and the other set of outlets is connected to the air inlet chamber (81) through the emergency pipe (72).

5. A contactless shaft seal structure for a dry vacuum pump according to claim 3 or 4, characterized in that, The storage capsule bag (84) contains cyanoacrylate quick-drying adhesive.

6. A contactless shaft seal structure for a dry vacuum pump according to any one of claims 1 to 4, characterized in that, A pressure sensor (9) is installed on the vacuum pump to monitor the pressure inside the gas seal ring.

7. A contactless shaft seal structure for a dry vacuum pump according to any one of claims 1 to 4, characterized in that, The medium end (1) and the motor end (2) are connected by a sealing seat (3). The shaft seal (5) is arranged at the center of the sealing seat (3). The sealing channel (51) is arranged radially along the sealing seat (3). A labyrinth seal (52) is also installed between the shaft seal (5) and the lubricating oil cavity of the motor end (2).

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