EP0389838A2

EP0389838A2 - Housing for rotary pump

Info

Publication number: EP0389838A2
Application number: EP90104379A
Authority: EP
Inventors: Candido Granes Campasol
Original assignee: Inoxpa SA
Current assignee: Inoxpa SA
Priority date: 1989-03-30
Filing date: 1990-03-07
Publication date: 1990-10-03
Anticipated expiration: 2010-03-07
Also published as: DE69005167D1; EP0389838A3; ES2013417A6; EP0389838B1; DE389838T1

Abstract

Improvemnts in the manufacture of rotary pumps characterized by the body of the pump which houses the lobar type rotors comprising a plate of a generally flat formation having orifices for passage of the rotor drive shafts and a pressed out casing which rests against the said plate thus determining the lateral and frontal rotor enclosure, the attachment of the two components being mutually capable of disassembly and being provided with means of sealing in the area of coincidence of the plate and the enclosure casing.

Description

This present Invention Patent discloses improvements in the manufacture of rotary pumps particularly of the type of pump based on the use of a lobar rotor.
This type of pump makes possible the transfer of various liquids without causing separation in the liquid being transferred given that the pumping action is volumetric, that is to say, taking a predetermined volume corresponding to the space between the rotor lobes and conveying it from the entry point of the liquid to the exit thus ensuring a continuous flow within the pipework or exit circuit at a pressure dependent on the circuit losses.
This category of pump is fitted with two rotors mounted on parallel axes actuated by a gear train in such a manner that the two rotors engage as mentioned previously. The two rotors rotate in a chamber defined by an enclosure body which in turn defines the periphery of the chamber and two side walls one of which is a closure plate fitted to the main pump body. The traditional method of construction of this type of pump takes the form of a rotor casing as mentioned above coupled up to the actuating gear train and closed by means of a front cover fitted to the open face of the said casing.
This mode of construction is costly on account of its mechanical features which include the high precision required in the closure plate as well as the stiffness and good sealing capability of that plate. This makes both the plate itself and the pump body expensive to produce.
The improvements object of this Invention Patent are designed to provide both the pump body and the enclosure component or front cover having absolutely novel design characteristics which result in a considerable manufacturing cost improvement in these items as well as offering functional qualities which resolve the difficulties in obtaining a satisfactory seal.
Essentially the improvements which are the object of this Patent are based on obtaining the complete pump body by the provision of a plate carrying the shaft seals and casing from a sheet pressing attached to the said plate thus completing the together the entire rotor chamber, the rotors being housed within this composite chamber and being driven by their corresponding shafts which traverse orifices in the seal retaining plate, the seals being fitted thereto.
In accordance with these improvements the driving shafts of the rotors terminate level with or below the outer plane of the said rotors so as to permit the pressed sheet casing to be almost fully level with the plane formed by the outer face of the said rotors.
A stepped flange on the periphery of the sealing plate coinciding with the side wall of the casing provides a simple means of sealing the chamber, the two elements being mutually joined with bolts and having interposed in the coincident area a sealing means.
For the better understanding of the improvements drawings are attached showing by way of one embodiment the objects of this Patent.

Figure 1 is a frontal elevation view of the rotary pump showing the improvements.
Figure 2 is a longitudinal section of the same pump.
Figures 3 and 4 are respectively views of the casing with sections for clarification.
Figures 5 and 6 are respectively transverse and front views of the seal retaining plate.

As is shown in the drawings the rotary pump provided with these improvements comprises a body formed by the seal retaining plate -1- through which passes the shafts -2- and -3- of the respective rotors -4- and -5- and a casing or cover -6- made for preference in a metal stamping and having one lateral face which determines the chamber housing the rotors -4- and -5- and the other frontal or closure face -7- which is adapted to the lateral faces of the rotors to provide the enclosed casing of the rotor chamber. Slight protrusions -8- and -9- on the front face -7- allow a clearance for the extremities of the shafts -2- and -3- so as to avoid interference.
The rotors -4- and -5- are mounted on the shafts -2- and -3- such that the front faces are practically level with the plane of the front surface of the rotors.
The seal retaining plate is a functional component in the assembly of the pump, having a generally flat structure with cavities to accept the seal assemblies -10- and -11- for the shafts -2- and -3- respectively and having also on its periphery a a stepped flange forming the wing -12--which is coupled up to the flat surface of hte flange -13- of the casing -6-, the positioning of these two components being mutually ensured by means of dowels -14- and the attachment by means of screws or other means which would permit disassembly. In the zone of coincidence in the angle corresponding to the seal retaining plate and the casing a space is provided to house a sealing material -16- such a flexible joint or other type of seal.
The assembly of the pump comprising the the two components mentioned above, that is the seal retaining plate -1- and the casing -6- are built on to the shaft drive chamber -17- as may be seen in Figure 2.
The casing -6- is provided with orifices -18- and -19- for the entry and exit of the fluid which is to be pumped.
As may be evident the improvements offered as object of this Patent provide a very simple construction for rotary pumps giving efficient and good technical characteristics with improvements in manufacturing costs of the components.
Anything not altering, modifying or changing the essence of the improvements as described herein is variable for purposes of this Patent.

Claims

1.- Improvements in the manufacture of rotary pumps characterized in the construction of the body of the pump, in which are housed the lobar type rotors, being comprised of a plate of generally flat form provided with holes for the shafts operating the rotors and a pressed sheet casing which rests against the said flat plate and defines the frontal and surrounding enclosure of the rotors, the two components being capable of disassembly one from the other and having in the zone where the plate and the casing coincide means of sealing.

2.- Improvements in the manufacture of rotary pumps as in Claim 1, characterized in that the plate having a generally flat form has at its area of contact with the casing component a zone forming a peripheral stepped flange which rests against a corresponding flat surface being a flange on the casing component the two being attached on the zone of coincidence formed by the said flange faces with dismountable means of attachment securing the said component assembly to the body which serves as guide and houses the gearing means driving both of the pump shafts.

3.- Improvements in the manufacture of rotary pumps as in Claim 2, characterized by the provision of sealing means in the space between the opposed corner angles formed at the inner edge of the two coincident flanges.

4.- Improvements in the manufacture of rotary pumps, as in Claim 2 or 3, characterized in that the flat plate is provided with sets of shaft glands in the position of the drive shafts so as to ensure sealing between the shafts and the plate.