WO2022053959A1

WO2022053959A1 - Vacuum pump

Info

Publication number: WO2022053959A1
Application number: PCT/IB2021/058189
Authority: WO
Inventors: Claudo FRISINGHELLI; Paolo CEOLA; Carmine MADDALENA
Original assignee: Mapro International Macchine Pneumatiche Rotative S.P.A.
Priority date: 2020-09-10
Filing date: 2021-09-09
Publication date: 2022-03-17
Also published as: KR20230062804A; CN115917153A

Abstract

Vacuum pump (1) comprising a machine body (2) configured to generate and maintain a pressure difference and a motor apparatus (3), operatively configured to generate driving power for an actuation of the machine body (2). The vacuum pump (1) further comprises a base (4) provided with a partition bulkhead (5) adapted to separate the machine body (2) from the motor apparatus (3) and configured for application to a separation wall between an environment at atmospheric pressure and an operating environment. The vacuum pump (1) comprises a mechanical transmission apparatus (6) interposed between the motor apparatus (3) and the machine body (2) and comprising a drive shaft (7) crossing such a partition bulkhead (5), wherein said drive shaft (7) extends integrally between a connection joint (8), arranged on one side of the partition bulkhead (5) facing the motor apparatus (3), up to the machine body (2).

Description

VACUUM PUMP

The present invention relates to a vacuum pump.

The present invention falls within the industrial sector and is particularly used in the methane gas supply chain.

As is known, methane gas can be transported by means of methane tankers.

In particular, the methane gas is stored on the methane tankers in storage tanks consisting of two concentric tanks, one inside the other.

Such tanks are separated by a gap, which acts as an isolating layer with very high efficiency based on the use of vacuum and/or material with isolation features.

To make the vacuum in such a gap, vacuum pumps are typically used to extract the air present in the gap.

Such vacuum pumps comprise a machine body, provided with a stator and a rotor cooperating in order to create a vacuum in the gap, and a motor apparatus suitable for actuating the machine body.

It is known to install such vacuum pumps so that the machine body is operatively connected inside the gap and thus arranged in a special room classified as a hazardous area while the motor apparatus is operatively arranged in an adjacent room classified as a safe area.

To this end, the base on which the machine body and the motor apparatus are fixed is provided with a partition bulkhead, which is configured to be seamlessly welded to the metallic partition wall of the two rooms.

Structurally, the transmission apparatus, interposed between the motor apparatus and the machine body, passes through the bulkhead and substantially comprises three drive shafts, arranged in series and connected by connection joints.

In particular, the intermediate drive shaft, provided with rigid ball bearings, is fixed to the bulkhead by means of flanging. Typically, moreover, a special double seal is installed on the intermediate drive shaft, for example with oil barrier, and provided with its own oil circulation circuit, storage and expansion tank and finned cooling tubes.

Although consolidated, such a solution has a plurality of disadvantages which make its use poorly performing.

First of all, the structure is extremely complex and consequently very expensive.

In fact, the presence of the intermediate drive shaft, provided with a special double mechanical seal, bearings, flanges and further mechanical components, results in a significant increase in the construction costs of the vacuum pump.

Furthermore, since such components are subject to wear and tear, they require a further increase in costs in case of maintenance and/or replacement.

A further problem concerns the installation step of the vacuum pump.

In particular, the alignment of the three drive shafts is a considerably burdensome process in terms of cost, time and labour due to the iterative nature thereof.

In fact, if at the end of the installation the drive shafts are not sufficiently aligned, the operators would be forced to repeat the alignment from the beginning.

In the light of the foregoing, the technical task of the present invention is to provide a vacuum pump capable of obviating the drawbacks which have just emerged.

An object of the present invention is to provide a vacuum pump which is structurally less complex and, consequently, less expensive.

A further object of the present invention is to provide a vacuum pump capable of being easily and quickly installed.

A further object of the present invention is to provide a vacuum pump which is durable over time and less subject to maintenance. The specified technical task and the specified aims are substantially achieved by a vacuum pump comprising one or more of the technical features set out in the appended claims. The dependent claims correspond to possible embodiments of the invention.

Such a description will be set out hereinafter with reference to the accompanying drawings given only for illustrative and, therefore, nonlimiting purpose, in which: figure 1 is a schematic depiction of a vacuum pump in accordance with the present invention; figure 2 is a schematic depiction of a sectional view of a detail of the vacuum pump of figure 1 .

With reference to the accompanying drawings, the reference numeral “1” globally indicates a vacuum pump in accordance with the present invention.

Such a vacuum pump 1 is configured for generating and maintaining a pressure difference between an operating environment and an environment at atmospheric pressure.

Essentially, the vacuum pump 1 comprises a machine body 2, a motor apparatus 3, a base 4, a mechanical transmission apparatus 6 and a sealing apparatus 9.

The machine body 2 is configured for generating and maintaining a pressure difference and comprises a stator and a rotor.

In particular, the rotor is inserted in the stator and is cooperating therewith to generate such a pressure difference.

Structurally, according to a preferred embodiment, the vacuum pump 1 is of the rotary vane vacuum pump type.

In particular, the rotor is inserted in the stator in an eccentric manner and comprises moving vanes constrained in sliding in respective seats obtained in the rotor.

The machine body 2 further comprises a lubrication circuit, preferably with oil. The machine body 2 is actuated by the motor apparatus 3, which is operatively configured for generating driving power for an actuation of the machine body 2.

According to a preferred, exemplary and non-limiting embodiment, the motor apparatus 3 comprises an electric motor.

The base 4, to which the machine body 2 and the motor apparatus 3 are permanently constrained, is configured to be anchored to a mounting surface.

Structurally, the base 4 comprises a partition bulkhead 5 suitable for separating the machine body 2 from the motor apparatus 3 and configured for application to a separation wall between the environment at atmospheric pressure and the operating environment.

In other words, according to a preferred use of the vacuum pump 1 , the partition bulkhead 5 is seamlessly welded to the metal partition wall between the environment at atmospheric pressure and the operating environment.

Preferably, the motor apparatus 3 is arranged in the environment at atmospheric pressure while the machine body 2 is arranged in the operating environment.

Such a feature is particularly advantageous in applications of the vacuum pump 1 in which the operating environment is classified as a hazardous area for the probable formation of a potentially explosive atmosphere while the environment at atmospheric pressure is classified as a safe area.

In fact, thanks to such an arrangement of the machine body 2 and the motor apparatus 3, an operator can reach and carry out maintenance operations on the motor apparatus 3 in absolute safety.

The mechanical transmission apparatus 6 is interposed between the motor apparatus 3 and the machine body 2 and comprises a drive shaft 7 crossing the partition bulkhead 5 through an opening obtained on the partition bulkhead 5. According to an aspect of the present invention, the drive shaft 7 extends integrally between a connection joint 8, arranged on one side of the partition bulkhead 5 facing the motor apparatus 3, up to the machine body 2.

In particular, the connection joint 8 is arranged to reversibly connect with the motor apparatus 3.

Preferably, such a connection joint 8 is an elastic connection joint.

Advantageously, through the presence of a drive shaft 7 which extends integrally between the connection joint and the machine body 2, passing through the partition bulkhead 5, the structure of the vacuum pump 1 is considerably simplified with a consequent reduction in construction costs. According to a further aspect of the present invention, the drive shaft 7 can be made in a single body with the rotor of the machine body 2.

Furthermore, the drive shaft 7 can be free of connection joints between the partition bulkhead 5 and the machine body 2.

Advantageously, such features contribute to further lowering the construction and installation costs.

In fact, the elimination of the intermediate drive shaft as well as the elimination of a connection joint facilitate the installation steps of the vacuum pump 1 .

Furthermore, the mechanical components cooperating with the intermediate drive shaft, and in particular the rigid ball bearings, are eliminated, reducing the costs and problems related to the wear thereof.

Moreover, advantageously, such a structure allows a significantly faster disassembly of the vacuum pump 1 in case of maintenance and/or replacement of the components.

The sealing apparatus 9, active between the partition bulkhead 5 and the drive shaft 7, is configured to prevent the passage of fluid between the environment at atmospheric pressure and the operating environment. According to a further aspect of the present invention, the sealing apparatus 9 can be of the double mechanical seal type, active on opposite faces of the partition bulkhead 5.

According to a preferred embodiment, illustrated by way of non-limiting example in the accompanying drawings, the sealing apparatus 9 can be of the oil barrier type and comprises an oil supply apparatus 10 and a cooling apparatus.

However, according to alternative embodiments, the sealing apparatus 9 may be a standard double mechanical sealing apparatus.

Furthermore, as can be seen in the accompanying drawings, the sealing apparatus 9 can be stably constrained to the partition bulkhead 5 by means of flanging.

According to a further aspect, as can be seen in the accompanying drawings, the vacuum pump 1 can comprise a coupling lantern 11 , operatively arranged near the opening obtained on the partition bulkhead 5, where said coupling lantern 12 is concentric to a front cover of the machine body 2.

Advantageously, such a feature allows a precise and rapid assembly of the sealing apparatus 9 to the mechanical transmission apparatus 6. Advantageously, moreover, such a feature allows

The coupling lantern 11 may further have one or more openings, obtained near the machine body 2, configured to put an inner portion of the coupling lantern 11 in communication with the operating environment in which the machine body 2 is inserted.

Advantageously, such a feature allows any leaks of the machine body 2 to be discharged into the operating environment.

According to another aspect of the present invention, the sealing apparatus 9 can comprise an axial expansion compensator 12 suitable to absorb any displacements of the partition bulkhead 5 during the normal operations of the vacuum pump 1 . In particular, such an axial expansion compensator 12 is operatively interposed between the partition bulkhead 5 and the flanging.

Advantageously, the present invention achieves the proposed object, overcoming the highlighted drawbacks of the prior art.

Firstly, the structure of the vacuum pump 1 is considerably simplified and consequently less expensive.

Such a result is obtained by the presence of a drive shaft 7 which extends integrally between the connection joint 8 and the machine body 2, where the elastic joint is arranged in reversible connection with the motor apparatus 3 and where the drive shaft 7 is made in a single body with the rotor, which allows the elimination of the intermediate drive shaft and the mechanical components cooperating therewith, causing a considerable reduction in costs.

Moreover, such a result is achieved by the possibility of using a standard double mechanical sealing apparatus 9, further reducing costs.

A further object achieved is that of providing a vacuum pump 1 capable of being easily and quickly installed.

For the same reasons, the presence of a drive shaft 7 which extends integrally between the connection joint 8 and the machine body 2 together with the presence of a connection joint 8 make the installation step clearly faster and easier.

A further object achieved is that of providing a vacuum pump 1 which is durable over time and less subject to maintenance.

Such a result is obtained by means of a substantial reduction of the mechanical components involved in the transmission of the driving power between the motor apparatus 3 and the machine body 2.

Claims

8 CLAIMS

1. Vacuum pump (1) for generating and maintaining a pressure difference between an operating environment and an environment at atmospheric pressure, comprising:

- a machine body (2) configured to generate and maintain a pressure difference and comprising a stator and a rotor, said rotor being inserted in said stator and cooperating with the stator to generate said pressure difference; said machine body (2) further comprising a lubrication circuit;

- a motor apparatus (3), operatively configured to generate driving power for an actuation of said machine body (2);

- a base (4), to which said machine body (2) and said motor apparatus (3) are stably constrained and configured to be anchored to a mounting surface; said base (4) comprises a partition bulkhead (5) adapted to separate said machine body (2) from said motor apparatus (3) and configured for application to a separation wall between said environment at atmospheric pressure and said operating environment so that said motor apparatus (3) and said machine body (2) are operatively arranged in said environment at atmospheric pressure and said operating environment, respectively;

- a mechanical transmission apparatus (6) interposed between said motor apparatus (3) and said machine body (2) and comprising a drive shaft (7) crossing said partition bulkhead (5) through an opening obtained on said partition bulkhead (5);

- a sealing apparatus (9) active between said partition bulkhead (5) and said drive shaft (7) and configured to prevent the passage of fluid between said environment at atmospheric pressure and said operating environment; wherein said drive shaft (7) extends integrally between a connection joint (8), arranged on one side of the partition bulkhead (5) facing the motor 9 apparatus (3), up to said machine body (2), said connection joint (8) being arranged with reversible connection with said motor apparatus (3).

2. Vacuum pump (1 ) according to claim 1 , wherein said drive shaft (7) is made in a single body with said rotor.

3. Vacuum pump (1) according to claim 1 or 2, wherein said drive shaft (7) lacks connection joints between said partition bulkhead (5) and the machine body (2).

4. Vacuum pump (1 ) according to any one of the preceding claims, wherein said sealing apparatus (9) is of the double mechanical oil barrier seal type and is active on opposite faces of said partition bulkhead (5).

5. Vacuum pump (1) according to claim 4, wherein said sealing apparatus (9) is of the oil barrier type and comprises an oil supply apparatus (10) and a cooling apparatus.

6. Vacuum pump (1 ) according to any one of the preceding claims, wherein said sealing apparatus (9) is stably constrained to said partition bulkhead (5) by means of flanging.

7. Vacuum pump (1) according to claim 6, comprising a coupling lantern (11 ) operatively arranged near said opening obtained on said partition bulkhead (5); said coupling lantern (11 ) being concentric to a front cover of the machine body (2).

8. Vacuum pump (1) according to claim 6 or 7, comprising an axial expansion compensator (12), operatively arranged between said partition bulkhead (5) and said flanging.