DE20005916U1 - Liquid ring pump - Google Patents

Description

Liquid ring pump

The invention relates to a multi-flow liquid ring pump according to the preamble of claim 1.
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A ring pump of this type is known from WO 99/32 791. Such a liquid ring pump has a working chamber with a rotatably driven impeller, to which an operating liquid is fed and which is set in rotation. The working chamber is also connected via a feed line to the medium, in particular air, that is to be sucked out. The liquid ring resting against the wall of the working chamber and the eccentrically arranged impeller form expanding and contracting chambers. This sucks in and compresses gas. The geometry determines the thickness of the liquid ring.

Excess operating fluid is discharged with the gas through the outlet opening. The known liquid ring pump has the disadvantage that in the case of high vacuums in the supply line, the operating fluid is not discharged sufficiently. Due to the low gas mass flow, a smaller amount of operating fluid is discharged through the outlet opening of the ring pump than is supplied to the ring pump. As a result, the amount of operating fluid in the ring pump increases. Depending on the operating conditions of the ring pump, there is a critical suction pressure at which the impeller can be destroyed. To avoid this, the ring pump was designed according to the state of the art to ensure that operation in the critical range was avoided by specifying the operating conditions. To prevent possible destruction in any case, an additional ventilation valve is provided in the supply line, which

A/Li - Gardner Denver Wittig GmbH

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opens below a certain predetermined pressure and supplies the ring pump with a sufficient gas mass flow. However, opening the ventilation valve has the major disadvantage that the quality of the vacuum to be created is severely impaired. 5

The invention is based on the object of developing a generic liquid ring pump in such a way that trouble-free operation is ensured even at very low pressures in the supply line.

The object is achieved by the features of the characterizing part of claim 1. The essence of the invention consists in providing a ventilation device through which air or another gaseous medium is supplied from outside to the working chamber of the liquid ring pump. This ensures that even with high vacuums in the supply line, there is a sufficient gas mass flow in the working chamber through which the operating liquid is discharged from the working chamber and the amount of operating liquid in the working chamber is prevented from rising above a critical point. Even with a completely closed supply line, trouble-free operation of the ring pump is ensured.

Further advantageous embodiments of the invention emerge from the subclaims.

Additional features and details of the invention emerge from the description of an embodiment based on the drawings. They show:

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Fig. 1 is a schematic representation of a liquid ring pump including supply device for the operating fluid,

Fig. 2 a view of a liquid ring pump according to Figure 1, 5

Fig. 3 is a central longitudinal section through the liquid ring pump according to Figure 1,

Fig. 4 is a cross-sectional view along the line IV-IV in Figure 3,

Fig. 5 is a cross-sectional view along the line V-V in Figure without rotor shaft, and

Fig. 6 is a cross-sectional view along section line VI-VI in Figure 3 without rotor shaft.

The basic structure for the operation of a multi-flow liquid ring pump 1 is shown in Figure 1. The liquid ring pump 1 is connected on the suction side to a supply line 2 in which negative pressure prevails when the ring pump 1 is operating. On the pressure side, the liquid ring pump 1 is connected to a discharge line 3 in which positive pressure prevails when the ring pump 1 is operating. To operate the liquid ring pump 1, an operating liquid reservoir 4 is provided which is filled with an operating liquid, in particular water, within predetermined maximum and minimum limits. At the lower end of the reservoir 4, an operating liquid supply line 5 is connected to the reservoir 4, which is connected to the liquid via an operating liquid cooling device 6.

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Ring pump 1 and is connected to it. A valve 7 for controlling the supply of the operating liquid is provided in the supply line 5. The liquid ring pump 1 is also connected to a ventilation line 8 which opens into the upper area of the storage tank 4 which is not filled with the operating liquid. The storage tank 4 is connected at its upper end to a storage tank ventilation line 9 which has an end 10 which is open to the environment.

The liquid ring pump 1 has an impeller housing 11 with a substantially rectangular cross-section, on the front sides of which a side plate 12 and a side plate 13 are provided. The side plates 12, 13 are screwed together with tie rods 14 running through the impeller housing 11, with corresponding recesses 15 being provided for this purpose in the edge area of the side plates 12, 13. A rotor shaft 16 is mounted in the side plates 12, 13, with a shaft pin 17 formed in one piece with the rotor shaft 16 protruding beyond the side plate 12 for the drive connection to a motor. In the upper area of the side plate 12, an inlet opening 18 is provided for connecting the supply line 2 and an outlet opening 19 for connecting the discharge line 3. The side plate 13 has an inlet opening 20 and an outlet opening 21 that are mirror-symmetrical to the side plate 12. The liquid ring pump 1 can be operated in such a way that only one of the inlet openings 18, 20 and one of the outlet openings 19, 21 is connected to the associated supply line 2 or discharge line 3 and the two unused openings are each closed by a plate 22.

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The impeller housing 11 encloses a cylindrical working chamber 23. The rotor shaft 16 in Figure 4 is arranged eccentrically to its central longitudinal axis 23a and offset upwards, on which an impeller 24 is attached, the outer diameter of which is smaller than the diameter of the working chamber 23 and which is arranged in such a way that the play between the impeller 24 and the upper part of the working chamber 23 is small. The impeller 24 has radially extending blades 26 curved in the direction of rotation 25. It is also possible to use straight, i.e. non-curved blades 26. In the upper two gussets of the impeller housing, an inlet connection channel 27 and an outlet connection channel 28 are provided, which run parallel to the longitudinal direction of the working chamber 23. In the gusset of the impeller housing 11 shown in Figure 4 at the bottom right, an operating fluid connection channel 29 and a ventilation connection channel 30 are provided, both of which run parallel to the longitudinal direction of the working chamber 23 and are separated from each other by a partition wall 31.

The side plates 12, 13 have a working chamber wall 32 or 33 that delimits the working chamber 23 at the front and a housing wall 34 or 35 that delimits the side plates 12, 13 to the outside. The side plates 12, 13 each have a hub 36 in the middle in which the rotor shaft 16 is mounted. Adjacent to the working chamber 23 there is a sealing housing 37 connected to the hub 36 in which a radial shaft seal 38 is accommodated. This seals together with the rotor shaft 16, which is surrounded in this area by a ring-cylindrical sealing bush 39. On the sides of the seal 38 facing away from the working chamber 23 there is a rolling bearing 40 surrounding the shaft 16 in which the shaft 16 is mounted. The rolling

bearing 40 is secured in a bearing housing 41. On the side plate 13 there is a cover 42 covering the end of the shaft 16. On the side plate 12 there is a corresponding cover 43 with a central opening 44 through which the pin 17 is guided outwards.

The side plates 12, 13 are essentially mirror-symmetrical with respect to the central plane 45, which is why only the structure of the side plate 12 is described in detail below. Several chambers are arranged between the working chamber wall 32 and the housing wall 34, which are described below with reference to Figure 6. In the half of the side plate 12 shown on the left in Figure 6, a suction chamber 46 is arranged, which is connected to the working chamber 23 via an inlet opening 47. In the upper right corner of the side plate 12 in Figure 6, a pressure chamber 48 is provided, which is connected to the working chamber 23 via an outlet opening 49. The suction chamber 46 and the pressure chamber 48 are separated from one another by a partition wall 50. Adjacent to the pressure chamber 48, a ventilation chamber 52 is provided, separated from it by a partition wall 51.

This is connected to the working chamber 23 via a working chamber wall ventilation hole 53. Adjacent to the ventilation chamber 52 there is an operating fluid chamber 54 which is separated from the chamber 52 by a partition wall 55 and from the chamber 46 by a partition wall 56. The chambers 46, 48, 52 and 54 are connected to the corresponding channels 27, 28, 30 and 29 respectively. The ventilation chamber 52 is open to the outside through a ventilation connection opening 57 which is provided in the housing wall 34. The ventilation line 8 is connected to the ventilation connection opening 57.

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The liquid chamber 54 has an operating liquid connection opening 58, which is provided in the housing wall 34. The bore 58 is connected to the line 5. The part of the hub 36 which delimits the operating liquid chamber 54 has a supply opening 59. 5

It is possible to provide a ventilation connection opening 57 in only one side plate 12 or 13. Furthermore, it is also possible to provide a bore 53 in only one side plate 12 or 13.

The function of the liquid ring pump 1 is explained below. A motor causes the shaft 16 and thus the impeller 24 to rotate in the direction of rotation 25. The working chamber 23 is connected to the supply line 2 via the inlet opening 47, the suction chamber 46, the channel 27 and the opening 18, through which the medium to be sucked out, in particular air, is fed to the working chamber 23. The operating liquid is fed to the working chamber 23 via the opening 58, the chamber 54, the channel 29 and the opening 59. As a result of the rotation of the impeller 24, the operating liquid is set in rotation. The liquid ring resting on the wall of the working chamber 23 and the eccentrically arranged impeller 24 form expanding and contracting chambers. This sucks in and compresses gas. The geometry determines the thickness of the liquid ring. The mixture of extracted gas and excess operating fluid is then discharged via the outlet opening 49, the chamber 48, the channel 28, the opening 19 and the discharge line 3. Air from outside enters the working chamber 23 through the opening 57, the channel 30, the chamber 52 and the bore 53. This is particularly important in the case of high vacuums in the supply line 2. Due to the

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Air is supplied to the working chamber 23 via a ventilation device formed by the elements, so that even at high vacuums the operating fluid in the working chamber 23 can be discharged and the working chamber does not fill up and the impeller 24 is not destroyed.

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Claims (10)

1. Liquid ring pump (1) a) with an impeller housing (11) which a) encloses a rotatably driven impeller (24) arranged in a working space (23) and b) has two front sides, b) with two side shields (12, 13), a) which are arranged on the two front sides of the impeller housing (11), b) which have at least one inlet opening (18, 20) for a supply line (2) for supplying a medium to be extracted to the working space (23), c) which have at least one operating fluid connection opening (58) for supplying an operating fluid to the working chamber (23) and d) which have at least one outlet opening (19, 21) for a discharge line (3) for discharging the operating fluid and the medium to be extracted from the working space (23), characterized in that c) at least one ventilation device leading from the working space (23) to the outside is provided for supplying air into the working space (23). 2. Liquid ring pump (1) according to claim 1, characterized in that the at least one ventilation device is arranged in at least one side plate (12, 13). - 3. Liquid ring pump (1) according to claim 1 or 2, characterized in that the ventilation device is provided in a side plate (12, 13). 4. Liquid ring pump (1) according to claim 1 or 2, characterized in that a ventilation device is provided in each side wall (12, 13). 5. Liquid ring pump (1) according to one of the preceding claims, characterized in that each side plate (12, 13) has a working chamber wall (32, 33) which delimits the working chamber (23) at the front. 6. Liquid ring pump (1) according to claim 5, characterized in that the ventilation device has a working chamber wall ventilation bore (53) arranged in at least one working chamber wall (32, 33). 7. Liquid ring pump (1) according to claim 5 or 6, characterized in that each side plate (12, 13) has a housing wall (34, 35) delimiting the respective side plate (12, 13) to the outside. 8. Liquid ring pump (1) according to claim 7, characterized in that the ventilation device has a ventilation connection opening (57) arranged in the housing wall (34, 35) and open to the outside. 9. Liquid ring pump (1) according to claim 8, characterized in that the working space wall ventilation bore (53) and the ventilation connection opening (57) of a side plate (12, 13) are connected to one another by a ventilation chamber (52) arranged in the respective side plate (12, 13). 10. Liquid ring pump (1) according to claim 9, characterized in that the ventilation chamber (52) of one side plate (12) and the ventilation chamber (52) of the other side plate (13) are connected by a ventilation connection channel (30) arranged in the impeller housing (11).