CN1027659C - Mechanical seal for high vacuum device - Google Patents

Abstract

The invention relates to a mechanical sealing device for a high-vacuum device. The wedge-shaped sealing ring comprises a wedge-shaped sealing ring, a hard alloy moving ring is arranged below the sealing ring, a pressing ring is arranged above the moving ring, and two static rings made of graphite are arranged below the moving ring, and the wedge-shaped sealing ring is characterized in that the moving ring and the static rings are made of soft materials and hard materials, the soft materials are made into narrow rings, the gap between the moving ring and a shaft is 1-3 mm, the end surface smoothness of the rings is 10-12, and when a rotating shaft moves in the axial direction and is not more than 5 microns, and the radial swinging is not more than 10 microns, the vacuum degree can be kept at 0.5 torr.

Description

Application of mechanical sealing in high-vacuum device

The present invention and the application of a kind of mechanical seal on high-vacuum installation, described mechanical seal are meant at the opening of described high-vacuum installation and stretch into motive sealing between wherein the running shaft.

Up to now, this mechanical seal only is provided with for preventing to leak outside, and for example, uses the compressor on refrigerating machine, presses in the turbosupercharging pump etc. on the device greater than external pressure, in order to prevent gas or liquid leakage.In addition, in the prior art, for example under vaccum working condition, that is to say external pressure greater than the operating mode of interior pressure under general use of sealing of reactor tamp sealing, promptly on the running shaft of need sealing part, be wrapped with the filler band of selecting for use, compress with gland again.Because the gland sealed sealability is relevant with the impaction state and the material state of gland, so make in this way sealing state is difficult to control, can not guarantee that the high vacuum reaction device works sustainedly and stably.In view of the foregoing, the present invention has been proposed.

The objective of the invention is: existing a kind of mechanical sealing element is used on the reaction device under the high vacuum operating mode, to prevent interior leakage as dynamic seal apparatus.Described high vacuum operating mode is meant: in this device, when the play of running shaft on axle is not more than 5 microns, radially wobble the degree of vacuum that this device when being not more than 10 microns has 0.5 holder.

The present invention realizes by following proposal: between promptly a kind of running shaft that is loaded on the opening on the high vacuum reaction device and stretches into, described mechanical seal, motive sealing face is perpendicular to spin axis or substantially perpendicular to spin axis, be provided with elastic element in the sealing part, auxiliary seal ring is to constitute the compensation mechanism of axial wearing and tearing, main formation also comprises: wedge shape sealing ring gland, rotating ring, stationary ring, cooling and lubricating oil inlet, cooling and lubricating oil pipe, stationary seat etc.

Be used for the mechanical seal device on the high-vacuum installation, comprise a wedge shape sealing ring, the rotating ring of a cemented carbide is housed below this V-shaped ring, a pressure ring is housed on wedge shape sealing ring, a wedge-type seal gland is housed on pressure ring, between gland and rotating ring, fixed with locating stud, below rotating ring, be provided with two stationary rings of making by graphite, thereby two radial sealing surfaces have been constituted, stationary ring is fixed in the stationary seat, one stationary seat is provided with cooling and lubricating oil pipe and cooling and lubricating oil inlet, auxiliary seal ring and spring compensating element and the buffering element as axially wearing and tearing is housed below stationary ring, in addition, also be equipped with and be used as the vacuum reaction device and stretch into motive sealing between wherein the running shaft;

The dynamic and static ring material is one soft one hard, and soft material is made narrow ring, and the differences of two rings are 1～3 millimeter;

Gap between dynamic and static ring and the axle is 1～3 millimeter;

End finish is 10～12, end face straightness h≤0.00009 millimeter;

When running shaft in the axial direction play be not more than 5 microns, radially wobble when being not more than 10 microns, degree of vacuum can remain on 0.5 the holder.

Adopt the principle of mechanical seal to be: between sealing surface, to keep a liquid film as thin as a wafer, this liquid film is to be formed by the coolant/lubricant between sealing surface, keep permanent working life and excellent sealing performance just to require liquid film produced between sealing surface the resistance pressure difference greater than the seal face both sides.For this reason, to the mechanical sealing element that is adopted following technical requirements need be proposed:

1. end face width: seal face is made of rotating ring and stationary ring, it is one soft one hard that their material can be selected for use, and it is one wide one narrow that sealing surface can be designed to, soft material make narrow ring, hard material make wide ring, so just make narrow ring by uniform wear and unlikely being embedded in the wide ring goes.When if rotating ring and stationary ring are all selected hard material for use, then two rings are all made narrow ring, and get identical end face width.End face width b value changes with different axle journeys, when the diameter of axle is the 16-120 millimeter, and b=3～6 millimeter, the differences of general two rings are 1～3 millimeter.

2. the gap between dynamic and static ring and the axle:

Generally get the 1-3 millimeter, different and different with selected material.Material in the standard is graphite, bronze or fills the ptfe plastic ring.When the diameter of axle was the 16-100 millimeter, this gap was got 1 millimeter; When the diameter of axle was the 110-120 millimeter, this gap was got 2 millimeters; When the diameter of axle of carbide ring was the 16-100 millimeter, this gap was got 2 millimeters; When the diameter of axle was the 110-120 millimeter, this gap was got 3 millimeters.

3. the technological requirement of end face:

End finish: 10-12;

End face straightness: h≤0.00009 millimeter

When described mechanical sealing element be used in the high vacuum reaction device and the running shaft that inserts into the inner between motive sealing the time force analysis as follows: end face pressure p end is the key factor that influences sealability and life-span.As the pressure of representing with the p bullet to produce by spring, be situated between with p and represent the pressure that produces by medium, be situated between with P and represent the pressure that produces by medium, the pressure that the P antirepresentation is produced by the liquid film counter-force, then

P end=P end-P Jie-P is anti-

General because the liquid film counter-force is very little, can ignore.When reaction device was in the high vacuum operating mode, the pressure that medium produces became negative value, and then following formula becomes:

P end=P bullet-P Jie-P is anti-

This shows that the pressure of the mechanical seal of this device increases, and has strengthened sealability.

Above-described service condition is: this device on-stream must guarantee running shaft in the axial direction play be not more than 5 microns, swing diametrically is not more than 10 microns, just can guarantee that this device maintains 0.5 degree of vacuum of holding in the palm.Analyze theoretically, the degree of vacuum of this device also can further improve.

Consulting accompanying drawing below elaborates to example of the present invention:

Accompanying drawing 1: be that this kind mechanical sealing element is installed in an outward appearance shaft side figure on the high vacuum reaction device.

Accompanying drawing 2: the internal structure sectional view that is mechanical sealing element.

As shown in Figure 1: described known mechanical sealing element is fixed on the vacuum reaction device as being spirally connected with conventional mode.In Fig. 2, can see, be welded with a flange plate 2 at the top of this vacuum reaction device 1, mechanical sealing element is fixed on this flange plate 2, make this vacuum reaction device 1 and stretch between wherein the running shaft 4 to reach motive sealing with screw 3.This mechanical sealing element comprises a wedge shape sealing ring 5, the rotating ring 6 of a cemented carbide is housed below seal ring 5, a pressure ring 7 is housed on seal ring 5, a wedge-type seal gland 8 is housed on pressure ring 7, between gland and rotating ring, fixed with locating stud 9, below rotating ring, be provided with two stationary rings of making by graphite 10, thereby two radial sealing surfaces have been constituted, stationary ring is fixed in the stationary seat 11, on stationary seat 11, be provided with cooling and lubricating oil pipe 12 main cooling and lubricating oil inlets 13, below stationary ring 11, be provided with auxiliary seal ring 14 and spring 15 compensating element and buffering element as axially wearing and tearing.In addition, also being provided with auxiliary catch 16 becomes flexible to prevent Sealing.

The present invention is the new application as a kind of known mechanical sealing element, this mechanical sealing element the vacuum reaction device and stretch into motive sealing performance between wherein the running shaft and sealing life aspect all have outstanding especially effect.

Claims (1)

1, a kind of mechanical seal device that is used on the high-vacuum installation, comprise a wedge shape sealing ring, the rotating ring of a cemented carbide is housed below this V-shaped ring, a pressure ring is housed on wedge shape sealing ring, a wedge-type seal gland is housed on pressure ring, between gland and rotating ring, fixed with locating stud, below rotating ring, be provided with two stationary rings of making by graphite, thereby two radial sealing surfaces have been constituted, stationary ring is fixed in the stationary seat, one stationary seat is provided with cooling and lubricating oil pipe and cooling and lubricating oil inlet, auxiliary seal ring and spring compensating element and the buffering element as axially wearing and tearing is housed below stationary ring, in addition, auxiliary catch also is housed, it is characterized in that described structure is being used as the vacuum reaction device and is stretching into motive sealing between wherein the running shaft by screw on the flange plate at vacuum reaction device top;

The dynamic and static ring material is one soft one hard, and soft material is made narrow ring, and the differences of two rings are 1～3 millimeter;

Gap between dynamic and static ring and the axle is 1～3 millimeter;

End finish is 10～12, end face straightness h≤0.00009 millimeter;

When running shaft in the axial direction play be not more than 5 microns, radially wobble when being not more than 10 microns, degree of vacuum can remain on 0.5 the holder.

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