Roots vacuum pump capable of automatically monitoring shaft end seal leakage

Abstract

The utility model belongs to the technical field of Roots vacuum pumps, and discloses a Roots vacuum pump capable of automatically monitoring shaft end seal leakage, which comprises a Roots vacuum pump body, the Roots vacuum pump body comprises a pump body, a motor front cover and a gear rear cover which are arranged on the front side and the rear side of the pump body, and an exhaust port arranged on the pump body, a self-detection leakage device is arranged on the Roots vacuum pump body; the leakage self-detection device comprises two helium leakage holes, a thermal diffusion helium concentration instrument and a helium concentration instrument mounting base; and the two helium leak holes are formed in the motor front cover and the gear rear cover respectively. According to the scheme, the leakage self-detection device consisting of the helium leakage hole and the thermal diffusion helium concentration instrument is additionally arranged, and the characteristics of small molecular weight and high diffusion speed of helium are utilized, so that the leakage problem of the shaft end mechanical seal of the roots vacuum pump can be detected in time, early detection of leakage is realized, and further deterioration of the leakage condition is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of Roots vacuum pumps, and more specifically, to a Roots vacuum pump with self-monitoring shaft end seal leakage. Background Art

[0002] The shaft ends of the four rotating parts of the Roots vacuum pump unit (as shown in Figure 1 ) are mostly sealed by mechanical seals. The mechanical seal is divided into a moving ring and a static ring. The moving ring is a smooth alloy ring, and the static ring is a smooth graphite ring. When the Roots vacuum pump is running, the moving ring rotates synchronously with the shaft, and the moving ring rotates closely against the graphite ring of the static ring. Since both are very smooth, the sealing effect is achieved to isolate the motor front cover and the gear rear cover from communicating with the pump cavity.

[0003] Oil contamination and subsequent damage to the graphite ring of the static ring, or wear of the graphite ring of the mechanical seal during long-term operation resulting in insufficient fitting strength with the moving ring, will cause mechanical seal leakage. These leaks are very small in the early stage. By the time the leakage is discovered, the leakage situation has passed for a long time, and in fact, it has affected the process production for a long time.

[0004] During the suction process of the Roots vacuum pump, if there is shaft end leakage, first, external air leaks into the pump cavity, affecting the vacuum degree; second, the lubricating oil of the Roots vacuum pump is sucked into the pump cavity and reacts with the process medium, affecting the product quality.

[0005] The discovery of the original shaft end leakage problem was mainly through observing the oil level in the sight glass of the lubricating oil of the Roots vacuum pump for a long time. The lubricating oil of the Roots vacuum pump was sucked into the pump cavity, and the oil level continued to drop. Then, the Roots vacuum pump was shut down for maintenance. At this time, the process medium had been contaminated, and the problem had existed for a long time. At present, there is no Roots vacuum pump with self-monitoring shaft end leakage on the market, and the market demand for such a Roots vacuum pump is very urgent. Content of the Utility Model

[0006] The purpose of the utility model is to solve the deficiencies existing in the prior art, and to propose a Roots vacuum pump with self-monitoring shaft end seal leakage.

[0007] To achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A Roots vacuum pump with self-monitoring shaft end seal leakage includes a Roots vacuum pump body. The Roots vacuum pump body includes a pump body, a motor front cover and a gear rear cover arranged on the front and rear sides of the pump body, and an exhaust port arranged on the pump body. A self-detection leakage device is arranged on the Roots vacuum pump body;

[0009] The self-detection leakage device includes two helium leakage holes, a thermal diffusion helium concentration meter and a helium concentration meter mounting base;

[0010] The two helium leak holes are respectively installed on the front cover of the motor and the rear cover of the gear, and the thermal diffusion helium concentration meter is installed on the exhaust port of the pump body through the helium concentration meter installation base.

[0011] As a further description of the above technical solution: The helium leak hole is a pressure vessel, and the two helium leak holes are respectively connected to the front cover of the motor and the rear cover of the gear through threads.

[0012] As a further description of the above technical solution: A ball valve is provided at the upper opening of the pressure vessel, and a molecular sieve is provided inside the pressure vessel.

[0013] As a further description of the above technical solution: The helium concentration meter installation base is a mating flange adapted to the exhaust port. A sealing ring is provided inside the mating flange. The mating flange is fastened to the exhaust port by screws, and the thermal diffusion helium concentration meter is fastened and installed on one piece of the mating flange through threads.

[0014] As a further description of the above technical solution: The thermal diffusion helium concentration meter is composed of a thermal conductivity helium concentration sensor and a thermal conductivity helium concentration sensor probe.

[0015] Compared with the prior art, the advantages of the present utility model are as follows:

[0016] By adding a self-detection leakage device composed of a helium leak hole and a thermal diffusion helium concentration meter in this solution, and utilizing the characteristics of small molecular weight and fast diffusion speed of helium, the leakage problem of the shaft end mechanical seal of the Roots vacuum pump can be detected in time, realizing the early discovery of leakage and avoiding the further deterioration of the leakage situation. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the connection of the shaft end mechanical seal in the prior art;

[0018] Figure 2 It is a schematic structural diagram of the present utility model;

[0019] Figure 3 It is a top view of the connection between the helium concentration meter installation base of the present utility model and the pump body;

[0020] Figure 4 It is a schematic structural diagram of the helium leak hole of the present utility model;

[0021] Figure 5 It is a schematic internal structure diagram of the helium leak hole of the present utility model;

[0022] Figure 6 It is a schematic structural diagram of the thermal diffusion helium concentration meter of the present utility model.

[0023] Explanation of the reference numerals in the drawings:

[0024] 1. Roots vacuum pump body; 11. Pump body; 12. Motor front cover; 13. Gear rear cover; 14. Exhaust port; 2. Helium leak hole; 21. Ball valve; 22. Molecular sieve; 3. Thermal diffusion helium concentration meter; 31. Thermal conductivity helium concentration sensor; 32. Probe of thermal conductivity helium concentration sensor; 4. Installation base of helium concentration meter; 5. Sealing ring. Detailed implementation mode

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] Please refer to Figure 2-6 , a Roots vacuum pump for self-monitoring shaft end seal leakage, including a Roots vacuum pump body 1. The Roots vacuum pump body 1 includes a pump body 11, a motor front cover 12 and a gear rear cover 13 arranged on the front and rear sides of the pump body 11, and an exhaust port 14 arranged on the pump body 11. A self-detection leakage device is arranged on the Roots vacuum pump body 1.

[0027] Among them, the self-detection leakage device includes two helium leak holes 2, a thermal diffusion helium concentration meter 3 and an installation base 4 of the helium concentration meter; the two helium leak holes 2 are respectively installed on the motor front cover 12 and the gear rear cover 13, and the thermal diffusion helium concentration meter 3 is installed on the exhaust port 14 of the pump body 11 through the installation base 4 of the helium concentration meter.

[0028] In the above solution: the chemical formula of helium is He, and the molecular weight is 3. It is a rare inert gas, very little in the air and has stable properties, and will not produce chemical reactions with the process medium. Therefore, a helium container is connected to the helium leak hole 2, and helium enters into the motor front cover 12 and the gear rear cover 13 from the helium leak hole 2.

[0029] Since the molecular weight of helium is small and the diffusion speed is fast, if there is a tiny leak at the mechanical seal and a negative pressure is generated in the pump chamber of the Roots vacuum pump, the helium in the motor front cover 12 and the gear rear cover 13 will be sucked into the pump chamber of the pump body 11 and discharged to the exhaust port 14.

[0030] The thermal diffusion helium concentration meter 3 arranged at the exhaust port 14 is used to detect the helium concentration at the exhaust port 14. Once helium is detected, the detected helium must come from the helium leaked from the motor front cover 12 or the gear rear cover 13 of the Roots vacuum pump. Then it is judged that the seals at the four shaft ends are damaged or excessively worn and need to be replaced or repaired, so as to realize the function of self-monitoring shaft end leakage.

[0031] Among them, the helium leak hole 2 is a pressure vessel. The two helium leak holes 2 are respectively connected to the front cover 12 of the motor and the rear cover 13 of the gear through threads, which is convenient for installation and connection. A ball valve 21 is provided at the upper opening of the pressure vessel. Opening the ball valve 21 can fill helium into the pressure vessel. A molecular sieve 22 is provided inside the pressure vessel, which can make the helium in the pressure vessel leak slowly at a fixed speed.

[0032] In addition, the installation base 4 of the helium concentration meter is a mating flange adapted to the exhaust port 14. A sealing ring 5 is provided inside the mating flange. The mating flange is fastened to the exhaust port 14 by screws. The thermal diffusion helium concentration meter 3 is fastened and installed on a piece of mating flange through threads. The thermal diffusion helium concentration meter 3 is composed of a thermal conduction helium concentration sensor 31 and a thermal conduction helium concentration sensor probe 32. The thermal diffusion helium concentration meter 3 monitors the helium concentration in the pump cavity in real time. Once helium leakage is detected, an alarm can be immediately issued to achieve real-time monitoring and early warning.

[0033] The above is only a preferred specific embodiment of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A Roots vacuum pump capable of self-monitoring shaft end seal leakage, comprising a Roots vacuum pump body (1), wherein the Roots vacuum pump body (1) comprises a pump body (11), a motor front cover (12) and a gear rear cover (13) arranged at the front and rear sides of the pump body (11), and an exhaust port (14) arranged on the pump body (11), characterized in that: The Roots vacuum pump body (1) is provided with a self-leakage detection device; The self-detection leakage device comprises two helium leak holes (2), a thermal diffusion helium concentration meter (3) and a helium concentration meter mounting base (4); The two helium leak holes (2) are respectively mounted on the motor front cover (12) and the gear rear cover (13), and the thermal diffusion helium concentration meter (3) is mounted on the exhaust port (14) of the pump body (11) via a helium concentration meter mounting base (4).

2. The Roots vacuum pump with self-monitoring shaft end seal leakage according to claim 1, characterized in that: The helium leakage hole (2) is a pressure container, and the two helium leakage holes (2) are respectively connected to the motor front cover (12) and the gear rear cover (13) through threads.

3. The Roots vacuum pump with self-monitoring shaft end seal leakage according to claim 2, characterized in that: A ball valve (21) is provided at the upper opening of the pressure container, and a molecular sieve (22) is provided inside the pressure container.

4. The Roots vacuum pump with self-monitoring shaft end seal leakage according to claim 1, characterized in that: The helium concentration meter mounting base (4) is a matching flange adapted to the exhaust port (14), a sealing ring (5) is provided in the matching flange, the matching flange is fastened to the exhaust port (14) by means of screws, and the thermal diffusion helium concentration meter (3) is mounted on a matching flange by means of threaded fastening.

5. The Roots vacuum pump with self-monitoring shaft end seal leakage according to claim 1 or 4, characterized in that: The thermal diffusion helium concentration meter (3) is composed of a thermal conduction helium concentration sensor (31) and a thermal conduction helium concentration sensor probe (32).

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