GB1577622A

GB1577622A - Hydrodynamic pump units

Info

Publication number: GB1577622A
Application number: GB1258277A
Authority: GB
Original assignee: PUMPEX PRODUCTION AB
Current assignee: PUMPEX PRODUCTION AB
Priority date: 1976-04-09
Filing date: 1977-03-25
Publication date: 1980-10-29
Also published as: SE7604234L; SE413540B; FR2353732B1; FR2353732A1

Description

(54) IMPROVEMENTS RELATING TO HYDRODYNAMIC PUMP UNITS (71) We, PUMPEX PRODUCTION AB of 370 Skebokvarnsvägen, S-124 34 Bandhagen, Sweden, a Swedish company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to hydrodynamic pump units and to regulators therefor.

By using pump units with a variable performance, considerable savings are achieved when building reservoirs or basins for accommodating flow variations, for instance pumping stations for the disposal of waste water, since reservoirs of smaller volume may be built. Increased inflow is matched by increased pump performance and no account needs to be taken of unpredictable inflow volumes.

Some pump units of the rotary hydrodynamic type for pumping liquids comprise a pump, a driving motor and a modifier connected thereto for obtaining a variable speed. On its input side, the said modifier is driven mechanically or electromegneticcally.

The speed modifier associated with the pump unit provides a significant reduction in the initial costs and also the operating costs of the complete pump unit.

In the present application the term modifier also includes such driving motors, preferably asynchronous motors which, by means of special devices, are adapted to permit operation at variable speed.

Typically, known speed modifiers are technically far from satisfactory. Thus, power losses of 5 to 80% /O of the power supplied are frequently recorded. The power losses are converted into heat and have to be dissipated to the environment. For this purpose it has been known to provide a speed modifier with cooling fins for air cooling or with separately mounted external air or liquid cooled radiators.

In some other cases the pumped liquid is permitted to pass through an external, separately mounted radiator in order to recover the heat which has been dissipated.

When the pump and the modifier are in the form of a unit, it is certainly possible to use external radiators as described, but the latter have then to be designed according to the characteristics of the liquid, complex and expensive radiator designs being required when polluted liquids or chemically aggresive liquids, such as waste water or acids are pumped.

The aim of the invention is to provide a pump unit of the kind specified which eliminates the last-mentioned disadvantages and can be made at reduced production costs.

The invention provides a pump unit for pumping a liquid, comprising in an encapsulating housing, a pump of the rotary hydrodynamic type provided with an impeller mounted on a driven shaft, a conditionresponsive, variable-speed driving means connected to said shaft for driving the impeller at a variable speed, said driving means having an internal chamber for receiving a volume of working liquid, wherein said chamber is arranged in a part of the said means which, when the unit is in operation, rotates, means being provided which, during said operation, continuously feed into and discharge from the chamber the working liquid at through-flow rates sufficient for continuously transferring away from the respective part of the driving means a portion of the heat energy generated therein in consequence of power losses, the arrangement being such that the continuous flow of the working liquid thus obtained is on at least one location outside said driving means for heat dissipating purposes brought into at least indirect thermal contact with the liquid pumped by the unit.

The advantages of the invention are achieved due to the fact that the increase in energy supplied to the liquid being pumped by the pump is utilised to reduce the area of heat transfer surfaces. Thus, it is possible to utilise for the heat transfer the surfaces usually used for encapsulation of the pump and of the modifier (variablespeed driving means).

The working liquid may be defined by a branched-off portion of the liquid pumped by the unit.

Said at least one heat dissipating location may be at least one surface within the pump and/or the driving means which is adapted for transferring heat to be dissipated to the liquid being pumped.

A member rotatable with the said driving means may be arranged to create an agitation of the working liquid in order to promote the heat dissipation.

An auxiliary pump may be provided for circulating the working liquid.

The driving means may include a hydraulic system, and the ordinary working liquid of said system may form the working liquid. The hydraulic system may comprise a slipping clutch which may advantageously be of the hydrodynamic type, preferably of the double-sided type.

Advantageously, when the unit is in use, said working liquid is forced against the internal walls of the said housing by centrifugal force.

The rotatable member may be a working liquid discharge pipe extending below the level of the working liquid collected in a sump.

The auxiliary pump means may be connected to the impeller input shaft and in that case the pressure from said auxiliary pump means is utilised for indicating or controlling the speed of said shaft. When the unit is in use, the pressure from the auxiliary pump means is supplied to a comparator which compares the controlled quantity and the pump speed, said comparator forming a part of a regulator.

At least the pump and the driving means may be adapted to be submerged in the liquid being pumped and sealed with respect to said liquid, the arrangement being such that, when the unit is in use, the heat to be dissipated is transferred to the liquid being pumped through at least a portion of the walls of said housing encapsulating the unit.

The driving means may be defined by a variable-speed electric motor and said feeding and discharging means may include a first conduit in the impeller input shaft for conducting the working liquid to the internal chamber in the rotor of said motor, and a second conduit in the impeller input shaft for discharging the working liquid from said chamber.

In a preferred embodiment the pump unit may comprise a rotary hydrodynamic pump having an impeller input shaft, a constantspeed driving motor having an output shaft, condition-responsive speed variation means operatively connecting said impeller input shaft to said motor output shaft for controlling the speed of rotation of said impeller input shaft relative to said motor output shaft, said speed variation means including a rotary hydrodynamic slipping clutch having an internal chamber and being connected to said motor and said pump by said housing, means for pumping working liquid to said clutch to control said relative speed of rotation and at the same time to absorb heat generated therein, and means for conducting the working liquid away from said clutch and towards a heat dissipating surface formed in said housing.

The pump unit may further include an annular chamber formed by the walls of said housing and defining said at least one heat dissipating location. It may also include means for conducting liquid from said chamber and into heat dissipating relationship with the liquid being pumped by said rotary pump.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a vertical section through a submersible pump unit comprising a pump of the centrifugal type and a modifier integral therewith, the modifier being defined by a hydrodynamic slipping clutch.

Figure 2 shows a pump unit having a pump housing and the associated driving means defined by an asynchronous motor acting as a modifier.

Figure 3 shows a modified pump unit together with its modifier, said modifier being of the "wet-clutch" type, i.e. an oil friction clutch.

Figure 4 shows a pump unit with a modifier and an indirect cooling system having an auxiliary pump disposed at the shaft sealing assembly.

The pump unit shown in Figure 1 comprises a pump of the centrifugal type having a pump housing 91 covered by a cover 93 and containing a pump impeller 92 attached to the bottom end of a driven shaft 112.

The shaft 112 is sealed by a shaft sealing assembly 94. The driving machine of the pump, an asynchronous motor, is denoted by 95 and 96 respectively, and has a driving shaft 97. On said shaft 97 a double-sided hydrodynamic slipping clutch having an upper member 98 and a lower member 99 is mounted. Impeller rims 110 and ill are provided, respectively, on the inner faces of the members 98 and 99. The driven shaft 112 supports at the top end thereof a disc 113. Impeller rims 114 and 115 are respec tively provided on both sides of the discs 113, so as to face the impeller rims 110 and 111 respectively.

The hydrodynamic slipping clutch is surrounded by a clutch housing 116 the lower portion of which forms a container 201 for a liquid 117. An auxiliary pump means 118 submerged in the liquid 117, is attached to the lower member 99 of the slipping clutch. The liquid 117 is pumped by a pump means 118 from the container 201 to a regulator valve 119 for the liquid flow, said valve 119 being controlled by a float 120 via a lever system. From the regulator valve 119 the liquid 117 flows to the interior spaces defined by the impeller rims 110, 111, 114 and 115 of the slipping clutch.

Upon rotation of the slipping clutch mem- bers 99 and 98 the motor torque is, in a manner known per se, transmitted to the driven shaft 112 by flow of the liquid in the spaces defined by the impeller rims. Owing to the pressure created by the liquid flow, together with the pressure from the auxiliary pump means 118, the liquid is forced to be discharged through a pipe 122 the mouth of which is directed towards the internal wall face of the housing 116 in order to spray it, whereby a relatively thin liquid film is created.

In the embodiment shown, the pump unit is submerged in a liquid 123 being pumped so that free suction from said liquid is possible. The liquid volume within the slipping clutch, i.e. the spaces defined by the impeller rims, which volume determines the pump speed, is controlled by the float 120, the regulator valve 119 and the discharge from the pipe 122. The power losses appearing when the clutch slips are transferred to the liquid 117 in the form of heat, which is dissipated from the liquid film on the walls of the housing 116, to said wails, and thence to the pumped liquid 123 surrounding the housing 116.

Alternatively, the pipe 122 may be disposed in the lower member 99 and may be extended in such a way that it opens below the level of the liquid 117 in the container 201. By the rotation of the pipe 122 and simultaneous discharge of liquid therefrom, the liquid 117 in the container 201 is agitated and effective heat transfer is achieved from an inner surface 124 of the bottom of the container 201 to an outer surface 125 thereof, past which the liquid 123 being pumped flows at a relatively high velocity and therefore has a high heat transfer capacity.

The location of the heat transfer sur faces may be varied considerably. Thus in stead of the surface 124 the heat transfer ring surface may be located above the upper side 126 of the pump impeller 92. Alter natively, instead of the surface 125 an annular channel 141 outside the wall of the housing 116 may be used, as shown in Figure 4. Moreover, in order to strain the liquid 123 being pumped, said liquid may be tapped off at the narrow gap shown above the upper surface 126 of the pump impeller 92 at a certain distance from the centre of the driven shaft 112 and may, after cooling of the clutch, be returned at a smaller dist ance, i.e. at a point at lower pressure, to the liquid 123 being pumped.

In a further alternative embodiment, the auxiliary pump means 118 is, for the purpose of achieving an increase in velocity of the liquid flowing past the cooling surfaces, located near the driven shaft 112, for instance in the shaft sealing unit 94.

Thus it is possible at the same time to supply the pressure from said auxiliary pump means 118 via a bore (not shown) to the outside of the pump unit in order to indicate there, on an instrument known per se, the speed of the driven shaft 112.

Alternatively it may possibly be connected to a conventional comparator which compares the quantity controlled, e.g. the liquid level, and the pump speed.

Figure 2 shows the invention applied to a short-circuited, variable speed, asynchronus motor. The additional losses in the rotor 127 appearing in the case of variation of the effective stator voltage, are transmitted to the liquid being pumped past heat exchanging surfaces 128 in the rotor 127. The liquid flows from a higher pressure point at the upper side of the pump im- peller, through a channel 129 to the rotor 127 and back through a channel 130 to a lower pressure point of the pump impeller 92. Alternatively, this direct cooling system may be replaced by an indirect system, wherein an auxiliary pump means, e.g. in the shaft sealing unit 92, circulates a liquid 131 between the cover 93 and the heat exchanging surfaces 128 in the rotor 127.

Figure 3 shows a pump having a liquid friction clutch which comprises an upper and a lower disc 132 and 133 and is driven by the motor shaft 97. The driven shaft 112 is provided with a disc 134 disposed between said discs 132 and 133. By means of the auxiliary pump means 118 the pressure of which acts on a piston 135, the discs 132 and 133 are pressed together. The pressure of the auxiliary pump means 118 is controlled via the float 120 by the dis charge of liquid in the valve 119. The fric tion heat between the discs 132 and 133 and 134 defining two interconnected cham bers is cooled by liquid from the auxiliary pump means 118 flowing through the holes 136 and 137 to said chambers and then out through grooves in the discs, from where the discharge liquid is thrown onto the walls of the housing 116.Alternatively, an indirect cooling system may be provided in that the liquid flow from the valve 119 is supplied to a surface disposed above the upper surfaces 126 of the pump impeller 92.

Figure 4 shows a modifier having an indirect cooling system comprising a second auxiliary pump means 138 disposed in the shaft sealing unit 94. A liquid 139 around said unit is pumped through a channel 140 into an annular chamber 141 around the housing 116 and is fed back via a channel 142 to the bottom of the cover 93, where it acquires a high dicsharge velocity in a return flow opening 143. The purpose of the first auxiliary pump means 118 is the same as in the embodiment according to Fig. 1, i.e., in principle, to fill the hydraulic clutch and to dissipate the heat to be dissipated therefrom to the walls of the housing 116 and chamber 141, the filling being controlled on the pressure side of the pump by means of the regulator valve 119.

The aforesaid pump unit has the advantage that it provides substantial energy savings.

The principle, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protcted is not, however, to be construed as limited to the particular forms disclosed, since these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by those skilled in the art without departing from the scope of the appended claims.

WHAT WE CLAIM 1S:- 1, A pump unit for pumping a liquid, comprising in an encapsulating housing, a pump of the rotary hydrodynamic type provided with an impeller mounted on a driven shaft, a condition-responsive, variable-speed driving means connected to said shaft for driving the impeller at a variable speed, said driving means having an internal chamber for receiving a volume of a working liquid, wherein said chamber is arranged in a part of the said means which, when the unit is in opeartion, rotates, means being provided which, during said operation, continuously feed into and discharge from the chamber the working liquid at through-flow rates sufficient for continuously transferring away from the respective part of the driving means a portion of the heat energy generated therein in consequence of power losses, the arrangement being such that the continuous flow of the working liquid thus obtained is on at least one loaction outside said driving means for heat dissipating purposes brought into at least indirect thermal contact with the liquid pumped by the unit.

2. A pump unit according to Claim 1, wherein the working liquid is defined by a branched-off portion of the liquid pumped by the unit.

3. A pump unit according to Claim 1 or 2, wherein said at least one heat dissipating location is at least one surface within the pump and/or the driving means which is adapted for transferring heat to dissipated to the liquid being pumped.

4. A pump unit according to Claim 1, 2 or 3, wherein a member rotatable with the said driving means is arranged to create an agitation of the working liquid in order to promote the heat dissipation.

5. A pump unit according to any one of the preceding claims, wherein an auxiliary pump means is provided for circulating the working liquid.

6. A pump unit according to any one of the preceding claims, wherein the driving means includes a hydraulic system, and the ordinary working liquid of said system forms the working liquid.

7. A pump unit according to Claim 6, wherein the hydraulic system comprises a slipping clutch.

8. A pump unit according to Claim 7, wherein the slipping clutch is of the hydrodynamic type.

9. A pump unit according to Claim 8, wherein the hydrodynamic slipping clutch is of the double-sided type.

10. A pump unit according to Claim 7, wherein, when the unit is in use, said working liquid is forced against the internal walls of the said housing by centrifugal force.

11. A pump unit according to Claim 4, wherein the said rotatable member is a working liquid discharge pipe extending below the level of the working liquid collected in a sump.

12. A pump unit according to any one of Claims 4 to 11, wherein the auxiliary pump means is connected to the impeller input shaft, and the pressure from said auxiliary pump means is utilised for indicating or controlling the speed of said shaft.

13. A pump unit according to Claim 12, wherein, when the unit is in use, the pressure from the auxiliary pump means is supplied to a comparator which compares the controlled quantity and the pump speed, said comparator forming part of a regulator.

14. A pump unit according to any one of Claims 3 to 13, wherein at least the pump and the driving means are adapted to be submerged in the liquid being pumped and sealed with respect to said liquid, the arrangement being such that, when the unit is in use, the heat to be dissipated is transferred to the liquid being pumped through at least a portion of the walls of said housing encapsulating the unit.

15. A pump unit according to Claim 5 when appended to Claim 1 or 2 wherein said driving means is defined by a variable

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Claims

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indirect cooling system may be provided in that the liquid flow from the valve 119 is supplied to a surface disposed above the upper surfaces 126 of the pump impeller 92.

Figure 4 shows a modifier having an indirect cooling system comprising a second auxiliary pump means 138 disposed in the shaft sealing unit 94. A liquid 139 around said unit is pumped through a channel 140 into an annular chamber 141 around the housing 116 and is fed back via a channel 142 to the bottom of the cover 93, where it acquires a high dicsharge velocity in a return flow opening 143. The purpose of the first auxiliary pump means 118 is the same as in the embodiment according to Fig. 1, i.e., in principle, to fill the hydraulic clutch and to dissipate the heat to be dissipated therefrom to the walls of the housing 116 and chamber 141, the filling being controlled on the pressure side of the pump by means of the regulator valve 119.

The aforesaid pump unit has the advantage that it provides substantial energy savings.

The principle, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protcted is not, however, to be construed as limited to the particular forms disclosed, since these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by those skilled in the art without departing from the scope of the appended claims.

WHAT WE CLAIM 1S:- 1, A pump unit for pumping a liquid, comprising in an encapsulating housing, a pump of the rotary hydrodynamic type provided with an impeller mounted on a driven shaft, a condition-responsive, variable-speed driving means connected to said shaft for driving the impeller at a variable speed, said driving means having an internal chamber for receiving a volume of a working liquid, wherein said chamber is arranged in a part of the said means which, when the unit is in opeartion, rotates, means being provided which, during said operation, continuously feed into and discharge from the chamber the working liquid at through-flow rates sufficient for continuously transferring away from the respective part of the driving means a portion of the heat energy generated therein in consequence of power losses, the arrangement being such that the continuous flow of the working liquid thus obtained is on at least one loaction outside said driving means for heat dissipating purposes brought into at least indirect thermal contact with the liquid pumped by the unit.
2. A pump unit according to Claim 1, wherein the working liquid is defined by a branched-off portion of the liquid pumped by the unit.
3. A pump unit according to Claim 1 or 2, wherein said at least one heat dissipating location is at least one surface within the pump and/or the driving means which is adapted for transferring heat to dissipated to the liquid being pumped.
4. A pump unit according to Claim 1, 2 or 3, wherein a member rotatable with the said driving means is arranged to create an agitation of the working liquid in order to promote the heat dissipation.
5. A pump unit according to any one of the preceding claims, wherein an auxiliary pump means is provided for circulating the working liquid.
6. A pump unit according to any one of the preceding claims, wherein the driving means includes a hydraulic system, and the ordinary working liquid of said system forms the working liquid.
7. A pump unit according to Claim 6, wherein the hydraulic system comprises a slipping clutch.
8. A pump unit according to Claim 7, wherein the slipping clutch is of the hydrodynamic type.
9. A pump unit according to Claim 8, wherein the hydrodynamic slipping clutch is of the double-sided type.
10. A pump unit according to Claim 7, wherein, when the unit is in use, said working liquid is forced against the internal walls of the said housing by centrifugal force.
11. A pump unit according to Claim 4, wherein the said rotatable member is a working liquid discharge pipe extending below the level of the working liquid collected in a sump.
12. A pump unit according to any one of Claims 4 to 11, wherein the auxiliary pump means is connected to the impeller input shaft, and the pressure from said auxiliary pump means is utilised for indicating or controlling the speed of said shaft.
13. A pump unit according to Claim 12, wherein, when the unit is in use, the pressure from the auxiliary pump means is supplied to a comparator which compares the controlled quantity and the pump speed, said comparator forming part of a regulator.
14. A pump unit according to any one of Claims 3 to 13, wherein at least the pump and the driving means are adapted to be submerged in the liquid being pumped and sealed with respect to said liquid, the arrangement being such that, when the unit is in use, the heat to be dissipated is transferred to the liquid being pumped through at least a portion of the walls of said housing encapsulating the unit.
15. A pump unit according to Claim 5 when appended to Claim 1 or 2 wherein said driving means is defined by a variable

speed electric motor, and said feeding and discharging means includes a first conduit in the impeller input shaft for conducting the working liquid to an internal chamber in the rotor of said motor, and a second conduit in the impeller input shaft for discharging the working liquid from said chamber.
16. A pump unit according to Claim 9 or 10 when appended to Claim 6 comprising a rotary hydrodynamic pump having an impeller input shaft, a constant-speed driving motor having an output shaft, conditionresponsive speed variation means operatively connecting said impeller input shaft to said motor output shaft for controlling the speed of rotation of said impeller input shaft relative to said motor output shaft, said speed variation means including a rotary hydrodynamic slipping clutch having an internal chamber and being connected to said motor and said pump by said housing, means for pumping working liquid to said clutch to control said relative speed of rotation and at the same time to absorb heat generated therein, and means for conducting the working liquid away from said clutch and towards a heat dissipating surface formed in said housing.
17. A pump unit according to Claim 16 when appended to Claim 5 further including an annular chamber formed by the walls of said housing and defining said at least one heat dissipating location.
18. A pump unit according to Claim 17, further including means for conducting liquid from said chamber and into heat dissipating relationship with the liquid being pumped by said rotary pump.
19. A pump unit constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in, Figure 1, Figure 2, Figure 3 or Figure 4 of the accompanying drawings.