EP3269984A1

EP3269984A1 - Pump equipped with improved flanges

Info

Publication number: EP3269984A1
Application number: EP17177919.2A
Authority: EP
Inventors: Giuliano Matteazzi; Alberto SAVEGNAGO; Fiorenzo Zamberlan
Original assignee: Calpeda SpA
Current assignee: Calpeda SpA
Priority date: 2016-07-13
Filing date: 2017-06-26
Publication date: 2018-01-17
Anticipated expiration: 2037-06-26
Also published as: EP3269984B1; IT201600072971A1; ES2727599T3

Abstract

The invention is a pump (1, 50) comprising: a pump body (2) in which there are a suction inlet (3) and a delivery outlet (4); a pumping unit (5) housed in the pump body (2) and configured to be connected to an electric motor (6) by means of a transmission shaft (7); a pair of flanges (8), one associated with the suction inlet (3) and one associated with the delivery outlet (4), each flange (8) comprising a flange body (10, 100) equipped with a front sealing surface (12) and a peripheral securing ring (14, 140) for connection to a corresponding counterflange. The securing ring (14, 140) is associated with the respective flange body (10, 100) by means of a threaded joint (16, 160) comprising a female thread (160a) which is located inside the securing ring (140) only for part (A1) of its thickness (A) and a male thread (160b) which is located outside the flange body (100) only for part (F1) of its thickness (F).

Description

DESCRIPTION

The invention relates to a pump equipped with improved flanges for connection to fluid suction and delivery pipes in a system.
It is known that in hydraulic systems the pumps that move the fluid are equipped with flanges to connect them to the suction and delivery pipes of the system.
As is known, each pump comprises a pump body in which there is a suction inlet and a delivery outlet and in which a pumping unit is housed which is rotated by a motor by means of a transmission shaft.
On the pump body, at the level of each suction inlet and delivery outlet, there is an associated flange which comprises at least one sealing surface at the front and peripherally a securing ring equipped with through holes for the insertion of the screws used to secure the flange to the counterflange of the corresponding suction or delivery pipe.
The suction and delivery pipes are in fact equipped with counterflanges which, like the flanges of the pump, are equipped with matching sealing surfaces and securing counter-rings with through holes for the securing screws. Operatively, when the securing screws are pulled by the tightening of the corresponding nuts, they force the sealing surface against the matching sealing surface respectively of the flange and the counterflange so as to achieve the hydraulic seal.
Preferably, a gasket is interposed between flange and counterflange.
A known pump of the type described is shown in Fig. 1 where the whole is indicated as A and in which the pump body C and the flanges B all pertain to a single cast piece.
Another known pump of the type described is shown in Fig. 2 where the whole is indicated as D and in which each of the flanges E with which it is equipped is secured by welding F to a connection sleeve G which is in turn fixed by a thread H to the body I of the pump.
In the pumps described and illustrated with reference to Figs. 1 and 2, but also in other pumps with different shapes but still pertaining to the prior art, each flange B, E has a peripheral annular surface defining the securing ring, respectively B1, E1, where the through holes B2, E2 for the securing screws are made.
In these pumps, therefore, the securing rings B1, E1 constitute a single-piece body which includes the corresponding flange.
Therefore, necessarily each flange and the corresponding securing ring are made of the same material which is usually suitable to withstand the corrosion of the fluid being pumped and therefore of a high quality and consequently expensive.
It is understood that if in the construction of the pumps the use of high-quality and expensive material for the flange area that comes into contact with the fluid could be limited and in contrast the securing ring which does not come into contact with the fluid could be made of less valuable material, it would be possible to save money and consequently reduce production costs of the pump.
Obviously, in the pumps of the prior art in which the securing ring is a single-piece body which includes the flange, this is not possible and thus the above constitutes a first limitation of the pumps of the prior art.
Another limitation of the pumps of the prior art is that given that the flanges are fixed and constitute a single body with the pump body, the alignment of the flange holes with the counterflange holes of the suction and delivery pipes may be rather complicated to achieve at times.
In fact, since the flanges are fixed they cannot be rotated angularly during assembly to line up the holes of the flange with those of the counterflange for the installation of the securing screws.
To attempt to overcome these limitations, patent document EP 0907029 provides a pump in which each flange comprises a flange body pertaining to the pump body and a securing ring in which through holes are made for the securing screws to the respective counterflange, which is coupled removably and rotatably peripherally to the flange body.
In particular, on the outer perimeter of each flange body and on the inner perimeter of each securing ring, perimeter grooves are machined with interconnecting profiles designed to define, when each securing ring is coupled to the respective flange body, a groove to house an elastic ring.
This, interfering elastically with the groove walls, allows the assembly and disassembly of the securing ring with respect to the flange body and ensures a stable union when coupled together.
Also, when assembled, the peripheral ring is integral with the flange but is free to rotate peripherally on it.
The solution described in the patent document cited above resolves first of all the problem of making a pump in which each flange comprises a securing ring separable from the flange body which can thus advantageously be made of a material other than that of the flange body itself, for example carbon steel, which has a much lower cost than, for example, stainless steel with which flange bodies are usually made.
Moreover, the presence of the elastic sealing ring placed peripherally between the flange body and the securing ring makes the latter freely rotatable on the respective flange body and enables the easy alignment of the fixing holes of the securing ring to the corresponding holes of the corresponding counterflange, unlike in the pumps of the known type.
The pump described in the aforementioned patent document EP 0907029 , together with the advantages that have been highlighted nonetheless also has some limitations that the present invention intends to overcome.
First of all, it should be noted that the pump described in patent document EP 0907029 has the limitation of requiring the use of a third element, in particular the elastic ring, in order to keep each securing ring peripherally attached to the corresponding flange body.
It is also necessary to machine the outer peripheral surface of the flange body and the internal perimeter surface of the securing ring to create the perimeter groove suitable to house the elastic ring.
Finally, it is impossible to carry out any intervention on the securing rings to move them axially so as to recover any existing distance differences from the counterflange to facilitate mounting operations.
The present invention aims to overcome these disadvantages.
In particular, an initial object of the invention is to provide a pump in which each flange comprises a fixed part of the flange body and a movable part still pertaining to the fixed part, independent and separable.
Another object is that the two fixed and mobile parts forming the flange can be connected together by means of connecting means pertaining to both parts. The objects listed are achieved by means of a pump the flanges of which are made according to the main claim to which reference will be made. Advantageously, the pump of the invention is less expensive than equivalent pumps of the prior art.
Also advantageously, the pump of the invention facilitates the connection of the flanges to the counterflanges of the suction and delivery pipes of a system. The objects and advantages listed and any others will be better illustrated below in the description of a preferred, but not exclusive embodiment of the pump of the invention which is provided with reference to the accompanying drawings in which:

Figs. 1 and 2 represent the longitudinal sections of two pumps belonging to the known art;
Fig. 3 shows the longitudinal section of the pump of the invention;
Fig. 3a shows an enlarged detail of the pump of Fig. 3;
Figs. 4, 5, 6 and 7 show details of other embodiments of the pump of Fig. 3. The pump of the invention is shown in Fig. 3 where it is indicated as a whole with 1.

Note that it comprises a pump body 2 in which there is a suction inlet 3 and a delivery outlet 4 and which houses a pumping unit 5.
Above the pumping unit 5 there is an electric motor 6, supported by the pump body 2, which rotates the pumping unit 5 by means of a transmission shaft 7 connected to the shaft of the electric motor 6.
In the pump body 2 there are a pair of flanges, each indicated with 8, one of which is associated with the suction inlet 3 and the other is associated with the delivery outlet 4.
Note that each flange 8 comprises a flange body 10 equipped frontally with at least one sealing plane 12 and peripherally with a securing ring 14 for the connection of the flange 8 to a corresponding counterflange pertaining to the suction and delivery pipes of a system, not shown in the drawing.
Preferably, a sealing gasket is inserted between each flange and the corresponding counterflange, not shown in the figure.
According to the invention, the securing ring 14 is associated with the respective flange body 10 by means of a threaded joint 16.
The threaded joint 16, as seen in Fig. 3a which represents an enlarged detail of Fig. 3 comprises a female thread 16a made in the securing ring 14 and a male thread 16b made outside the flange body 10.
As far as the flange body 10 is concerned, it is located at the end of a connection sleeve 18 which protrudes from the pump body 2 where the flange body 10, connection sleeve 18 and pump body 2 are connected to each other by means of fastening means, indicated as a whole by 20.
These fastening means 20 may be equally welds 20a, as in the case described in Figs. 3 and 3a, or threads, or other fixing means.
In another embodiment that is not shown here, the flange body, the connection sleeve and the pump body are made in a single-piece body.
According to another embodiment that is observed in the enlarged detail of Fig. 4, the pump of the invention, generally indicated by 50, differs from the embodiment just described only because the connection sleeve 180 is composed of two sections in which a first section 181 is associated with the flange body 10, a second section 182 is associated with the pump body 2 and the first section 181 and the second section 182 are interconnected by means of a threaded joint collar generally indicated by 183.
In particular, the threaded joint collar 183 comprises a male thread 181a made in the first portion 181 of the connection sleeve 180 and a female thread 182a made in the second portion 182 of the connection sleeve 180.
According to another embodiment shown in Fig. 5, the threaded joint collar 183 comprises a female thread 181b made in the first section 181 of the connection sleeve 180 and a male thread 182b made in the second section 182 of the same connection sleeve 180.
For all of the embodiments and variants described above, it is possible to execute a new embodiment of the threaded joint, generally indicated by 160, which is shown in Figs. 6 and 7.
This embodiment varies from the embodiment described above only because in the threaded connection 160 the female thread 160a involves only a part A1 of the thickness A of the securing ring 140 and the male thread 160b involves only a part F1 of the thickness F of the flange body 100.
In this way, with reference to Fig. 6, the partial threading of the thickness of the securing ring 140 and the flange body 100 allows the axial blocking of the securing ring 140 when being screwed to the flange body 100 when their reciprocal position is as shown in Fig. 6.
Conversely, the securing ring 140 can be separated from the flange body 100 when being unscrewed, as shown in Fig. 7.
Given the description it is understood that the pump of the invention achieves all the intended purposes.
In particular, the object of providing a pump in which each flange only has the flange body in contact with the fluid constructed with high quality material, usually stainless steel, while the securing ring which is not in contact with the fluid is made of common and less valuable material, such as carbon steel, is achieved.
Advantageously, this helps lower pump production costs.
Moreover, advantageously, given that the securing ring is independent and rotatably integral with the flange body, it can easily be rotated to align the through holes of the securing screws with the corresponding counterflange holes thus facilitating the installation of the pump.
The pump of the invention with a securing ring rotatably associated with the flange body by means of a threaded joint is also less costly to produce than equivalent pumps having the securing ring associated with the flange body with the interposition of third fastening elements such as for example the pump described in document EP 0907029 which requires the creation of a groove to house an elastic stop ring in the flange body and the securing ring.
If, during the production phase, modifications or variations that have not been described in the description above and are not shown in the drawings are made to the pump of the invention and particularly its flanges, and if such modifications and variants fall within the scope of the claims which will follow, they shall all be considered protected by the present invention.

Claims

Pump (1, 50) comprising:
- a pump body (2) in which there are a suction inlet (3) and a delivery outlet (4);

- a pumping unit (5) housed in said pump body (2) and configured to be connected to an electric motor (6) by means of a transmission shaft (7);

- a pair of flanges (8), one associated with said suction inlet (3) and one associated with said delivery outlet (4), each of said flanges (8) comprising a flange body (10, 100) having at least one front sealing surface (12) and peripherally a securing ring (14, 140) associated with the respective flange body (10, 100) by means of a threaded joint (16, 160) comprising a female thread (16a, 160a) made on the inside of said securing ring (14, 140) and a male thread (16b, 160b) made on the outside of said flange body (10, 100),
characterized in that said female thread (160a) involves only a part (A1) of the thickness (A) of said securing ring (140) and said male thread (160b) involves only a part (F1) of the thickness (F) of said flange body (10, 100).
Pump (1, 50) according to any of the preceding claims, characterized in that said flange body (10, 100) is located at the end of a connection sleeve (18, 180) protruding from said pump body (2).
Pump (1, 50) according to claim 2, characterized in that said flange body (10, 100), said connection sleeve (18, 180) and said pump body (2) are connected to one another by means of fastening means (20).
Pump (1, 50) according to claim 3, characterized in that said fastening means (20) are welds (20a).
Pump (1, 50) according to claim 3, characterized in that said fastening means (20) are threads.
Pump (1, 50) according to claim 2, characterized in that said flange body (10, 100), said connection sleeve (18, 180) and said pump body (2) are a single-piece body.
Pump (1, 50) according to any of the claims 2 to 5, characterized in that said connection sleeve (180) comprises a first section (181) with which said flange body (10, 100) is associated and a second section (182) with which said pump body (2) is associated, said first section (181) and said second section (182) being interconnected by means of a threaded joint collar (183).
Pump (1, 50) according to claim 7, characterized in that said threaded joint collar (183) comprises a male thread (181 a) / female thread (181b) made in said first section (181) and a female thread (182a) / male thread (182b) made in said second section (182).