JPS6011693A - Rotary pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to rotary pumps having two or more trochanters within the housing.

(2) Conventional technology roots blower type (1% oois blower type)
In known rotary pumps, such as the P.E.P. pump, two or more steel or cast iron trochanters rotate within the pump housing. Pot ugings are also made of steel or cast iron. Aluminum trochanter... also known as Uzing. When the metal trochanters are rotated in opposite directions, they simultaneously straighten the suction side relative to the discharge side without touching each other, so that they rotate around each other in a sealed sheet.8 This movement is effected by gears positioned in a special housing screwed into the pump housing. The trochanter is supported on both sides.

The gear r is positioned externally in a bearing provided at the end of the shaft of the trochanter.

Problems to be Solved by the Invention However, rotary pumps with such a structure generally have major drawbacks.

For example, applying excessive heat loads, squeezing or pinching with external objects, or adjusting gears (3) may cause the trochanters to contact each other or the trochanters and housing pump to contact each other. Become. As a result of welding the trochanters together or of the trochanters to the pump/uzing, sparks can be produced and locally intense (warming) can occur, especially if an explosive gas mixture is present in the uzing pump. Dangerous. Sparks or localized heating may cause an explosion, thus destroying the pump or even causing greater damage.

Another disadvantage of metal trochanters is their heavy weight. Since the moment of inertia associated with such a trochanter is high, a high torque is required at the time of starting. Additional problems arise when controlling the rotational speed and eliminating imbalances. Furthermore, for reasons of trochanter strength and stability, small diameter shafts require some wall strength. This limits the displacement of the pump.

SUMMARY OF THE INVENTION The present invention provides a rotary pump whose specific suction capacity, i.e. the suction capacity relative to the weight of the pump, is considerably improved compared to conventional designs (4). It is something. The invention also provides for increased reliability of operation, especially when pumping explosive gases. Furthermore, it is necessary to avoid the generation of sparks when the trochanters come into contact with each other or when the trochanters come into contact with the oozing.

Achieving the above objective must not be accompanied by any hindrance to the operation of the pump. This requires, in particular, that the properties of the materials used meet the high requirements determined by the operation and application of the pump. The present invention provides a rotary pump having a housing containing two or more trochanters, at least one of which is made of a non-metallic material having a coefficient of thermal expansion equal to or less than the coefficient of thermal expansion of the material of the housing. This is what we provide.

Advantageously, the non-metallic material of the trochanter has stability in shape and durability in mechanical strength.

In order to improve the performance of rotary pumps as vacuum pumps, materials with low degassing rates are selected. Plastic materials or even fiber mixtures with fillers made of fiber materials are suitable for the trochanter as they meet the technical specifications (5) requirements. Preferably, the fiber mixture trochanter is made by a twisting or winding method.

Pump housings can still be made from non-metallic materials.

Even if the trochanters come into contact with each other or the trochanter and/or the uzing, no spark is generated, so explosive substances can be carried. In order to avoid static charges, which can also cause sparks, the materials used can be reinforced with conductive fillers, for example carbon, which increases the conductivity. The materials used are chemically resistant to the substances being conveyed, in particular hydrocarbons and vapors, and to temperatures above 200°C. The physical properties and shape of the trochanter are also unaffected. If the thickness of the material used is thin, the moment of inertia of the trochanter will be lowered, making starting easier. The problems associated with balancing the trochanter and controlling its rotational speed are largely avoided.

There is an advantage that the thinner the material of the trochanter is, the more the material can have a shape with better volumetric efficiency (6). The relationship between the trochanteric diameter J) and the distance a between the axes is more selective in the dog than was previously possible. Therefore, if the diameter of the trochanter is made smaller, the shaft portion of the trochanter becomes smaller and therefore the volumetric space becomes larger.

The relationship between the suction volume and the space requirements of the pump is also improved by arranging the trochanter and gear between the bearings. The structure of the pump could be made even smaller, and the lever arm, which serves as the bearing for the drive trochanter, could be made very short. The fact that the housing and gear chamber are made of one piece allows for manufacturing advantages compared to conventional rotary pumps.

One preferred embodiment of the invention will be described by way of example below with reference to the accompanying drawings.

Volumetric space 8 formed by example pump housing 7vC
Two trochanters 1.2 are positioned inside. A trochanter shaft 6.4 rotates in a bearing 5.6. The trochanter shaft 6 is driven by, for example, a cone belt. The trochanter shaft 4 is driven via gears 11, (7) 12. These rotations are carried out in the gear chamber 13.
It is done within.

The two trochanters rotate in opposite directions within the volume chamber 8 .

Therefore, the conveyed medium is conveyed from the inlet side 9 to the outlet side.

One of the trochanters 1.2 is made of non-metallic material. The other trochanter can be made of the same material, steel, cast iron or other material.

In one variant (not shown), the pump has only one trochanter made of non-metal.

[Brief explanation of the drawing]

FIG. 1 shows the pump in section perpendicular to the trochanter, and FIG. 2 shows the pump in section parallel to the trochanter. 1.2... Trochanter 5.6... Bearing 7...
...Housing 8 ...Using chamber 11.12
...Gear 13...Gear chamber (8) Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] (1) Contains two or more trochanters made of a non-metallic material, at least one of which has a coefficient of expansion equal to or less than the coefficient of expansion of the material of the housing; A rotary pump characterized in that it has a housing. (2) A rotary pump according to claim 1, wherein the non-metallic material of the trochanter has resistance to hydrocarbons. The rotary pump according to claim 1 or 2, wherein the non-metallic material of the trochanter is resistant to steam. (4) The non-metallic material of the trochanter is resistant to temperatures above 200°C. (5) The material of the trochanter has a pressure of 1.10-2 mbar in vacuum.
- A rotary pump according to any one of the above items having a degassing rate of 1/s or less. (1) (6) A rotary pump according to any of the above items, wherein the non-metallic material is a plastic material having fibers as a filler. (Power) The rotary pump according to any one of claims 1 to 5, wherein the trochanter of the non-metallic material is made of a fiber composite material. (8) The non-metallic material is reinforced with a conductive filler. A rotary pump according to any one of the above items. (9) A rotary pump according to any one of the above items in which the ratio of the diameter of the trochanter to the distance a between the axes of the trochanter is greater than d. 00) The rotary pump according to any one of the above items. The rotary pump according to any one of the preceding clauses, wherein the gear is disposed between the bearings. Old) A rotary pump according to any one of the above items, consisting of an expansion chamber and a gear chamber in which the housing is integrally formed.