GB2037372A

GB2037372A - Rotary Positive-displacement Fluid-machines

Info

Publication number: GB2037372A
Application number: GB7943496A
Authority: GB
Original assignee: OS BAD ROZWOJOWY MECH
Current assignee: OS BAD ROZWOJOWY MECH
Priority date: 1978-12-18
Filing date: 1979-12-18
Publication date: 1980-07-09
Also published as: DE2949397A1; PL211931A1

Abstract

An internally meshing screw pump is provided with an inner rotor 1 and an outer rotor 5 mounted in bearings 3, 6 within the casing, characterised in that the helical surfaces are shaped so that they cause rotation of the rotors 1, 5 about their axes, which are fixed and mutually parallel. <IMAGE>

Description

SPECIFICATION Worm Pump This invention relates to worm pumps, particularly one having a rotor of one winding turn smaller than the winding of the worm hole of its housing. The pump is preferably designed for displacement of various kinds of dense and contaminated media.

Austrian Patent Application No. 320439 of Netzsch-Mohnopumpen GmbH discloses a worm pump having a rotor in the form of a single-turn worm whose cross-sections are circular, and arranged round the main axis of the rotor along a helix and distant from it by a constant value "a", and a stator provided with an inner hole shaped like a double-turn worm whose lead is two times bigger than the lead of the helix of the rotor. The normal section of the rotor hole is in a form of two semicircles extended from each other by the value of 4 "a". Such a configuration of the surface of the rotor-stator working elements means that while turning the rotor round its own axis, that axis is displaced around a circle of radius "a", centred on the axis of symmetry of the stator. This necessitates an articulated joint between the rotor and the transmission shaft of the pump.The articulation has to meet a number of requirements which are technically difficult because of the transfer of a determined driving torque and longitudinal force.

Moreover, the pump needs to be resistant to the harmful influence of the medium being pumped, and wrapping of fibrous materials contained in the agent being transported should be avoided.

Another type of worm pump, known from West German Patent Specification No. 1 928318 of Mono Pumps Ltd., London, features flexible operation of a rotor in a stator obtained by joining the rotor to a transmission shaft of considerable length. Such a pump is dynamically unbalanced due to the planetary motion of the rotor. As a result, the speed of rotation must be kept low, and the eccentricity value "a" must be reduced, which limits the obtaining of high parameters of transport from any particular unit. This makes it necessary to apply, in most cases, a speed reducer between the flexible motor and the pump.

The essence of the solution according to the invention consists in a different kinematic arrangement of the working elements, i.e. the stator and the rotor. The rotor is mounted in the body of the pump in such a way that it can move only by rotation about its own axis of symmetry.

Similarly, the stator is mounted in the body of the pump so that it can move only by rotation about its own axis of symmetry, said axis being shifted in relation to the axis of symmetry of the rotor by the eccentricity value "a". The stator is preferably mounted in bearings. The rotating rotor causes the stator to rotate due to the appropriate shaping of the working surface. The direction of rotation of the stator is in conformity with that of the rotor, but the angular velocity of the stator is half that of the rotor. A pump of such kinematics is dynamically balanced, and therefore there is no limit as to the rotational speed of the rotor, which in consequence makes possible higher parameters of delivery from any particular unit.

Moreover, this fact renders it possible to apply bigger eccentricity values "a", which is particularly advantageous when pumping liquids contaminated with large solid bodies or when transporting a medium whose internal structure should not be deformed. This is because, as the eccentricity "a" increases, the dimensions of the closed operating chambers moving along the pump also increase. In this kinematic arrangement the axis of the rotor does not change its position during operation, which means that additional devices such as cutters and files can be assembled directly on the rotor.

This arrangement eliminates the necessity of employing an articulated element in the power transmission of the rotor, so that the shape of the inlet and outlet channels can be devoid of sharp curves and elements which could possibly cause wrapping of fibrous materials present in the medium being pumped. This can ensure smooth flow through the whole pump.

At the same time the elimination of an articulated element increases the durability and reliability of the device, thus allowing considerable technical and economic advantages in production and exploitation.

Especially advantageous exploitation conditions and economic effects are obtained due to the possible increase in eccentricity, and, in connection with this, to the increase in suctionforce chambers. This is very important when transporting dense media, containing solid suspended matter.

The invention is further illustrated with reference to the accompanying drawing, which shows a longitudinal section of a pump.

A rotor 1 is mounted for rotation in a housing of channels 2 by means of bearings 3 which are separated from the channels of the liquid flow by means of a seal 4. A stator 5 is mounted in bearings 6 in the housing of the channels 2, and is sealed with seals 7. The axis of rotation of the stator 5 is displaced in relation to the axis of symmetry of the rotor 1 by a value "a", said axis of symmetry of the rotor 1 being the axis of symmetry of the pump.

Claims

1. A pump having a rotor and a stator, in which the rotation axes of the rotor and of the stator are parallel but laterally displaced; the working surfaces of the rotor and of the stator are so shaped that rotation of the rotor causes rotation of the stator.

2. A pump according to claim 1, in which the rotor and the stator are mounted in bearings.

3. A pump substantially as herein described with reference to the accompanying drawing.

4. A worm pump provided with a rotor and a stator bearing-mounted in the body of the pump,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Worm Pump This invention relates to worm pumps, particularly one having a rotor of one winding turn smaller than the winding of the worm hole of its housing. The pump is preferably designed for displacement of various kinds of dense and contaminated media. Austrian Patent Application No. 320439 of Netzsch-Mohnopumpen GmbH discloses a worm pump having a rotor in the form of a single-turn worm whose cross-sections are circular, and arranged round the main axis of the rotor along a helix and distant from it by a constant value "a", and a stator provided with an inner hole shaped like a double-turn worm whose lead is two times bigger than the lead of the helix of the rotor. The normal section of the rotor hole is in a form of two semicircles extended from each other by the value of 4 "a". Such a configuration of the surface of the rotor-stator working elements means that while turning the rotor round its own axis, that axis is displaced around a circle of radius "a", centred on the axis of symmetry of the stator. This necessitates an articulated joint between the rotor and the transmission shaft of the pump.The articulation has to meet a number of requirements which are technically difficult because of the transfer of a determined driving torque and longitudinal force. Moreover, the pump needs to be resistant to the harmful influence of the medium being pumped, and wrapping of fibrous materials contained in the agent being transported should be avoided. Another type of worm pump, known from West German Patent Specification No. 1 928318 of Mono Pumps Ltd., London, features flexible operation of a rotor in a stator obtained by joining the rotor to a transmission shaft of considerable length. Such a pump is dynamically unbalanced due to the planetary motion of the rotor. As a result, the speed of rotation must be kept low, and the eccentricity value "a" must be reduced, which limits the obtaining of high parameters of transport from any particular unit. This makes it necessary to apply, in most cases, a speed reducer between the flexible motor and the pump. The essence of the solution according to the invention consists in a different kinematic arrangement of the working elements, i.e. the stator and the rotor. The rotor is mounted in the body of the pump in such a way that it can move only by rotation about its own axis of symmetry. Similarly, the stator is mounted in the body of the pump so that it can move only by rotation about its own axis of symmetry, said axis being shifted in relation to the axis of symmetry of the rotor by the eccentricity value "a". The stator is preferably mounted in bearings. The rotating rotor causes the stator to rotate due to the appropriate shaping of the working surface. The direction of rotation of the stator is in conformity with that of the rotor, but the angular velocity of the stator is half that of the rotor. A pump of such kinematics is dynamically balanced, and therefore there is no limit as to the rotational speed of the rotor, which in consequence makes possible higher parameters of delivery from any particular unit. Moreover, this fact renders it possible to apply bigger eccentricity values "a", which is particularly advantageous when pumping liquids contaminated with large solid bodies or when transporting a medium whose internal structure should not be deformed. This is because, as the eccentricity "a" increases, the dimensions of the closed operating chambers moving along the pump also increase. In this kinematic arrangement the axis of the rotor does not change its position during operation, which means that additional devices such as cutters and files can be assembled directly on the rotor. This arrangement eliminates the necessity of employing an articulated element in the power transmission of the rotor, so that the shape of the inlet and outlet channels can be devoid of sharp curves and elements which could possibly cause wrapping of fibrous materials present in the medium being pumped. This can ensure smooth flow through the whole pump. At the same time the elimination of an articulated element increases the durability and reliability of the device, thus allowing considerable technical and economic advantages in production and exploitation. Especially advantageous exploitation conditions and economic effects are obtained due to the possible increase in eccentricity, and, in connection with this, to the increase in suctionforce chambers. This is very important when transporting dense media, containing solid suspended matter. The invention is further illustrated with reference to the accompanying drawing, which shows a longitudinal section of a pump. A rotor 1 is mounted for rotation in a housing of channels 2 by means of bearings 3 which are separated from the channels of the liquid flow by means of a seal 4. A stator 5 is mounted in bearings 6 in the housing of the channels 2, and is sealed with seals 7. The axis of rotation of the stator 5 is displaced in relation to the axis of symmetry of the rotor 1 by a value "a", said axis of symmetry of the rotor 1 being the axis of symmetry of the pump. Claims

4. A worm pump provided with a rotor and a stator bearing-mounted in the body of the pump, characterized in that a rotor and a stator have their longitudinal axes invariably displaced in relation to each other, and the working surfaces are shaped so that they cause rotation of the stator and the rotor round their own axes.