EP0389838B1

EP0389838B1 - Housing for rotary pump

Info

Publication number: EP0389838B1
Application number: EP19900104379
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: 1993-12-15
Anticipated expiration: 2010-03-07
Also published as: EP0389838A3; DE389838T1; DE69005167D1; EP0389838A2; ES2013417A6

Description

This present Invention relates to a rotary pump, particularly of the type of pump based on the use of lobar rotors.
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.
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 (EP-A-0 225 937). 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 object of the invention is to provide a rotary pump in which due to a novel design of the pump body a considerable manufacturing cost improvement is achieved, while a satisfactory seal is obtained.
This object is achieved by the features of the characterizing part of claim 1.
In accordance with the invention 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 the 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.

Claims

A rotary pump having a pump body, in which are housed lobar type rotors (4, 5), characterized in that the pump body comprises a plate (1) of generally flat form provided with holes for the shafts (2, 3) operating the rotors and a pressed sheet casing (6) which rests against the said flat plate (1) and defines the frontal and surrounding enclosure of the rotors (4, 5), the two components being capable of disassembly one from the other and having sealing means (16) in the zone where the plate (1) and the casing (6) coincide.
The rotary pump as in Claim 1, characterized in that the plate (1) has at its area of contact with the casing (6) a zone forming a peripheral stepped flange (12) which rests against a corresponding flat surface being a flange (13) on the casing (6), the two being attached on the zone of coincidence formed by the said flange faces with dismountable means (14, 15) of attachment securing the said pump body (1, 6) to a part (17) which serves as guide and houses the gearing means driving both of the shafts (2, 3).
The rotary pump as in Claim 2, characterized by the provision of sealing means (16) in the space between the opposed corner angles formed at the inner edge of the two coincident flanges (13, 12).
The rotary pump as in Claim 2 or 3, characterized in that the flat plate (1) is provided with sets of shaft glands (10, 11) in the position of the drive shafts (2, 3) so as to ensure sealing between the shafts (2, 3) and the plate (1).