CN101551016A - Shaft sealing device for high-temperature pressure-proof star-type feeder - Google Patents

Abstract

The invention provides a shaft sealing device of a high-temperature and pressure-resistant star feeder. The shaft seal adopts a combination of a mechanical seal and an air seal, including a rotating shaft 4, a high wear-resistant shaft sleeve 3, a first lip seal 1, and a second lip seal. Two-lip seal 2 and housing 5, in the pneumatic conveying device of dry granular medium, the technical solution of the present invention can ensure that the shaft end sealing device can be extended under a certain pressure (0.6MPa) and temperature (up to 300°C). service life and improve its performance.

Description

A shaft sealing device for a high-temperature and pressure-resistant star feeder

technical field

The invention belongs to the field of pneumatic conveying of powdery or granular materials, in particular to a shaft sealing device of a high-temperature and pressure-resistant star feeder.

Background technique

Boiler bottom slag (dry slag) in the electric power industry is crushed by a steel belt conveyor and a secondary slag crusher, and the particle size is controlled within 5mm. In the slag bin at the end. Due to the large material size and poor fluidity of the slag, when there is too much slag entering the pipeline instantaneously, it will cause difficulty in transportation. Therefore, a star feeder is installed at the discharge port of the conveying device (that is, the entrance of the conveying pipeline) to realize Feed evenly. The operating temperature of the conveyed slag medium is about 300 degrees, the highest impact temperature can reach about 350 degrees instantaneously, and the maximum medium pressure can reach about 0.6MPa. As shown in Figure 2, the shaft end sealing device of the high-temperature and pressure-resistant star feeder in the prior art adopts a combined seal of an air seal and a packing at the shaft seal. Wear on the shaft, under the action of the sealing gas, a gap will be formed between the shaft and the packing, resulting in seal damage, medium leakage, and increased wear on the shaft under the action of the air-ash mixture, so the sealing life of the prior art is short , and the temperature and pressure aspects can not meet the requirements.

As shown in Figure 1, the shaft end sealing device of the prior art high-temperature and pressure-resistant star feeder has a short sealing life, and the sealing parts need to be replaced in about 10 days. The environmental impact of the boiler room is relatively large, and the fastest time to replace the shaft end seal and sealing parts is 1 hour. The high temperature resistance and pressure bearing performance of some shaft end sealing devices cannot meet the requirements of industrial operation. The feeder is often stuck due to large particles of slag media entering the gap of the shaft end seal.

Therefore, the object of the present invention is to solve the problems of the prior art shaft end sealing device having too short service life, insufficient high temperature resistance and pressure resistance. And because the conveyed slag medium is a mixture of gas and solid, general mechanical seals need to be cooled by liquid, which cannot meet the working conditions of high-temperature and pressure-resistant star feeders in power systems. However, the high-temperature and pressure-resistant star feeder of the present invention The shaft end sealing device of the feeder can fully meet the requirements of the equipment for high temperature resistance and pressure resistance without liquid cooling. The shaft end sealing device of the present invention adopts a new type of sealing structure, and the medium pressure it can withstand is 0.6MP when the working temperature is 300°C. And the shaft end sealing device of the present invention adopts the combination of mechanical seal and air seal, without liquid lubrication and cooling, the working temperature can reach 300°C, the instantaneous impact temperature can reach 350°C, and its service life can reach one year.

Contents of the invention

The invention proposes a shaft sealing device and method for a high-temperature and pressure-resistant star feeder. The shaft seal adopts a combination of a mechanical seal and an air seal, and is characterized in that it includes a rotating shaft, a high wear-resistant shaft sleeve, and a first lip seal. , the second lip seal and the housing, the rotating shaft and the shaft sleeve are sealed by an O-ring, and there are two seals on the shaft sleeve: the first lip seal and the second lip seal, and the seal with the shaft sleeve is Dynamic seal, an air pressure chamber is formed between the first lip seal and the second lip seal, and the air pressure chamber is continuously filled with gas to form a sealing pressure when the feeder is working, and the sealing gas is provided by a special Provided by a gas source, the pressure of the sealing gas is greater than the air pressure on the crushed slag medium side of the feeder. When the feeder is working, the first lip close to the crushed slag medium side is sealed at the pressure difference between the pressure of the sealing gas and the crushed slag medium side. Under the action of the action, an air-filled gap is formed between the shaft sleeve and the first lip seal, so as to ensure that no debris medium enters between the first lip seal and the shaft sleeve, so that the surface of the first lip seal and the shaft sleeve will not be worn , relative to the first lip seal, the second lip seal on the side away from the slag medium is in close contact with the shaft sleeve under the sealing pressure of the sealing gas, so as to ensure that the slag medium and sealing gas will not leak. A high wear-resistant sleeve is set between the lip seal and the second lip seal.

Wherein, at least two airtight holes are provided on the outside of the air pressure chamber for filling gas into the air pressure chamber from a gas source.

Wherein, the high wear-resistant bushing is made of high wear-resistant alloy material.

Wherein, the first lip seal and the second lip seal are made of high temperature resistant modified tetrafluorocarbon material.

The beneficial effects of the present invention are: the maximum pressure resistance of the shaft end sealing device and method of the high temperature and pressure resistant star feeder of the present invention can reach 0.6 MPa, and the life of its wearing parts can be maintenance-free within one year, and the shaft seal The highest temperature resistance can reach 300 degrees Celsius without cooling.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is a structural schematic diagram of the shaft sealing device of a high-temperature and pressure-resistant star feeder in the prior art, in which, 1-housing, 2-air sealing ring, 3-packing, 4-air sealing hole, 5-packing Gland, 6-axis;

Fig. 2 is a structural schematic diagram of the high temperature and pressure resistant star feeder shaft sealing device of the present invention, wherein, 7-first lip seal, 8-second lip seal, 9-shaft sleeve, 10-rotating shaft, 11-shell Body, 12-pressure chamber, 13-airtight hole.

Detailed ways

In conjunction with Fig. 1, it is a schematic structural view of the high-temperature and pressure-resistant star feeder shaft sealing device of the present invention. Made of grinding alloy material, such as silicon carbide composite SS316L, the shaft 10 and the shaft sleeve 9 are sealed by an O-ring, and the shaft sleeve 9 is equipped with two seals: the first lip seal 7 and the second lip seal 8, The seal between it and the shaft sleeve 9 is a dynamic seal, and two air-tight holes 13 are provided between the first lip seal 7 and the second lip seal 8 .

In the pneumatic slag conveying system, the inlet of the feeder using this device is installed at the outlet of the conveying tank, and the conveying pipeline is installed under the outlet. The actual temperature of the bottom slag in the conveying tank is 300°C, and the maximum impact temperature is 350°C. The air pressure is 0.5MPa, the sealing gas pressure is 0.6MPa, and the rotor speed is 46rpm, the effect is better.

The invention has been described herein in terms of specific exemplary embodiments. Appropriate substitutions or modifications will be apparent to those skilled in the art without departing from the scope of the present invention. The exemplary embodiments are illustrative only, and not limiting of the scope of the invention, which is defined by the appended claims.

Claims (4)

1. A shaft sealing device and method for a high-temperature and pressure-resistant star feeder, which uses a combination of a mechanical seal and an air seal at the shaft seal, and is characterized in that it includes a rotating shaft 10, a high wear-resistant shaft sleeve 9, and a first lip seal 7. The second lip seal 8 and the housing 11, the rotating shaft 10 and the shaft sleeve 9 are sealed by an O-ring, and the shaft sleeve 9 is equipped with two seals: the first lip seal 7 and the second lip seal. Two lip seals 8, the seal between it and the shaft sleeve 9 is a dynamic seal, an air pressure chamber 12 is formed between the first lip seal 7 and the second lip seal 8, and the air pressure chamber is constantly controlled when the feeder is working. Gas is filled to form a sealing pressure. The sealing gas is provided by a dedicated gas source. The pressure of the sealing gas is greater than the air pressure on the crushed slag medium side of the feeder. When the feeder is working, the first The first lip seal forms an inflatable gap between the shaft sleeve and the first lip seal under the action of the pressure difference between the sealing gas pressure and the side air pressure of the debris medium, so as to ensure that no debris medium enters between the first lip seal and the shaft sleeve , so as not to cause wear to the surface of the first lip seal and the shaft sleeve, the second lip seal on the side away from the slag medium relative to the first lip seal is in close contact with the shaft sleeve under the sealing pressure of the sealing gas, thus ensuring The slag medium and sealing gas will not leak, and a high wear-resistant shaft sleeve 9 is set between the rotating shaft and the first lip seal 7 and the second lip seal 8 . 2. The shaft sealing device and method according to claim 1, characterized in that at least two air-tight holes 13 are provided outside the air pressure chamber 12 for filling the air pressure chamber with gas from a gas source. 3. The shaft sealing device and method according to claims 1-2, characterized in that the high wear-resistant shaft sleeve 9 is made of high wear-resistant alloy material. 4. The shaft sealing device and method according to claims 1-3, characterized in that the first lip seal 7 and the second lip seal 8 are made of high-temperature-resistant modified PTFE material.

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