PUMP SYSTEM WITH MEDIUM-COOLED LIQUID PUMP

Description

[0001] The invention relates to a pumping system with a collecting tank for liquid and to a liquid pump with a housing which forms a suction opening, a pump chamber, an outlet nozzle and a motor chamber, a shaft which is rotatably mounted in the housing and on which an impeller is arranged within the pump chamber and on which a rotor of an electric motor is arranged in a section lying outside the pumped medium, which rotor is surrounded by a stator arranged in the motor chamber, wherein the liquid pump is mounted on the collecting tank (22) in such a way that the axis of the shaft runs vertically and the housing with its suction opening is immersed in the liquid, while the motor chamber is located above a maximum liquid level of the liquid.

[0002] A pump system of this type is known from DE 12 75 362 B.

[0003] JP S53 97 402 U and US 4 747 757 A describe medium-cooled liquid pumps which are designed as submersible pumps so that under normal operating conditions the housing, including the part containing the motor, is completely immersed in the liquid in the collecting basin and the motor can therefore be cooled by the surrounding medium. However, since it cannot be ruled out that under certain conditions the liquid level in the collecting basin drops so far that the part of the housing containing the motor is no longer covered by liquid and is therefore no longer sufficiently cooled, the pressure line leading from the pump chamber in this pump is connected to a cooling jacket which surrounds the motor so that the pumped medium flows around the motor. In this way, cooling of the motor by the pumped medium is ensured at all times.

[0004] Pumps are known from DE 601 26 061 T2 and DE 201 05 322 U1 in which the pumped medium is used to cool the motor.

[0005] In pump systems where the pump is only immersed in the liquid to be pumped with its suction opening, while the part of the housing containing the motor is always above the liquid level, air-cooled pumps are used, as with these pumps there is no risk of liquid from the collection tank getting into the air cooling system for the pump motor.

[0006] The object of the invention is to create a pump system with high performance and low installation height.

[0007] This object is achieved according to the invention in that a cooling jacket surrounding the motor chamber, which has a cylindrical shape and forms an annular chamber, is in fluid communication with the pump chamber on the one hand and with the outlet nozzle on the other hand, wherein a pressure line connecting the pump chamber to the cooling jacket opens into the cooling jacket in a first circumferential position and the outlet nozzle is connected to the cooling jacket in a second circumferential position and the first and second circumferential positions are diametrically opposite one another.

[0008] The basic idea of ​​the solution according to the invention is that even in pump systems in which an air-cooled pump could be used safely, a medium-cooled pump with a cooling jacket surrounding the motor is used.

[0009] The advantage of this solution is that even with pumps that may be subject to high continuous loads, no fan is required to generate a cooling air flow and therefore the installation height, measured from the bottom of the collecting basin to the top of the pump housing, can be significantly reduced.

[0010] The first and second circumferential positions of the cooling jacket are diametrically opposite each other. From the pressure line, the medium then branches into two streams that flow around the motor chamber in opposite directions of rotation and rejoin upon entering the outlet nozzle.

[0011] Advantageous embodiments and further developments of the invention are specified in the subclaims.

[0012] The pressure line enters the lower end of the cooling jacket, while the outlet connection is preferably arranged radially at the upper end of the cooling jacket, so that the flow of the medium in the cooling jacket also has an upward component. This prevents the formation of zones with low fluid exchange in the cooling jacket and simultaneously facilitates venting of the pump. An exemplary embodiment is explained in more detail below with reference to the drawing.

[0013] They show: Fig. 1 is an axial section through a pumping system according to an embodiment of the invention; and Fig. 2 is a section along the line II-II in Fig. 1 .

[0014] The Fig. 1 The pump shown has a housing 10 which forms a suction opening 12 in the region of its lower end and a pump chamber 14 further above. A shaft 16 is rotatably mounted in the housing 10 and carries at least one impeller 18 within the pump chamber 14. In the example shown, a cascade of three radial impellers is provided which convey the medium sucked in via the suction opening 12, for example a cooling liquid, into a pressure line 20 which emerges from the upper end of the pump chamber 14 in a position radially offset from the shaft 16.

[0015] In the example shown, the pump is mounted in a collecting tank 22 for the cooling liquid such that the axis of the shaft 16 is oriented vertically and the suction opening 12 is located just above the bottom 24 of the collecting tank 22. The liquid level 26 of the liquid in the collecting tank 22 is indicated by a dashed line. The pump is submerged in the cooling liquid with its lower part, which forms the suction opening 12, the pump chamber 14, and the lower part of the pressure line 20, while the upper part of the pump is located above the liquid level 26. This upper part of the housing 10 accommodates an electric motor 28, which can thus be better protected against the harmful effects of the pumped medium.

[0016] The shaft 16, with its section located above the liquid level 26, is axially fixed in the housing 10 by means of rolling bearings 29 and passes through a motor chamber 30, which is closed at the upper end by a cover 32. A rotor 34 of the electric motor is arranged within the motor chamber 30 in a rotationally fixed manner on the shaft 16 and is surrounded by a stator 36, which is held stationary in the motor chamber 30 and is in thermal contact with a peripheral wall 38 of the motor chamber via its outer peripheral surface.

[0017] The motor chamber 30 is surrounded over most of its height by a cooling jacket 40, the walls of which are formed in one piece with the peripheral wall 38 of the motor chamber. The cooling jacket 40 has a cylindrical shape overall and forms an annular chamber 42. The pressure line 20 opens into a first circumferential position A, on the right in Fig. 1 , into the lower end of the annular chamber 42. In a circumferential position B diametrically opposite to the first circumferential position A, left in Fig. 1 , a radially extending outlet nozzle 44 is connected to the upper end of the cooling jacket 40, through which the medium pumped by the pump enters a delivery line (not shown). However, the outlet nozzle is still located below the upper winding heads of the stator, which in this example protrude above the cooling jacket. Thus, the outlet nozzle can be arranged at the upper end of the cooling jacket for better ventilation without increasing the overall height of the pump.

[0018] When the pump is in operation, the liquid is sucked in through the intake opening 12 and pressed through the pressure line 20 into the annular chamber 42 of the cooling jacket 40. In the first circumferential position A, the flow of the medium branches into two branches, which flow around the motor chamber 30 in opposite directions and reunite in the circumferential position B, as shown in Fig. 2 indicated by arrows.

[0019] In the example shown here, the medium flowing through the annular chamber 42 forms a closed body of water around the pump motor, which is not interrupted by any sound bridges, thus achieving good sound insulation and thus very quiet running of the pump.

[0020] In an embodiment not according to the invention, the mouth of the pressure line 20 and the transition to the outlet nozzle could also be close to each other and separated by a partition wall.

[0021] The height of the cooling jacket 42 can be dimensioned so that the winding packages of the stator 36 are specifically cooled.

[0022] How Fig. 1 As shown, the motor chamber 30, which also houses the roller bearings 29 for the shaft 16, is sealed from the interior of the collecting basin 22 by a shaft seal 46. Optionally, the pump can be equipped with a level sensor and an electronic control system, which detects the liquid level 26 and regulates it so that it always remains safely below the position of the shaft seal 46.

[0023] In this example, the peripheral wall of the pump chamber 14 is formed by three stacked and sealed ring modules 48, each of which accommodates one of the impellers 18. The intake opening 12 is formed in a separate housing section, which is connected to the rest of the housing by tie bolts 50. In this way, the ring modules can be tightly and securely clamped together. After loosening the tie bolts 50 and removing the separate housing section, the number of ring modules 48 and impellers 18 can be varied as needed or depending on the available height.

Claims

1. A pumping system with a collecting basin (22) for liquid and comprising a liquid pump (10) with a housing (10) which forms a suction opening (12), a pump chamber (14), an outlet connection piece (44) and a motor chamber (30), the pumping system further comprising a shaft (16) which is rotatably mounted in the housing and on which an impeller (18) is arranged inside the pump chamber (14) and on which a rotor (34) of an electric motor (28) is arranged in a section lying outside the pumped medium, the rotor being surrounded by a stator (36) arranged in the motor chamber (30), the liquid pump (10) being mounted on the collecting basin (22) in such a way that the axis of the shaft (16) extends vertically and the housing (10) is immersed with its suction opening (12) in the liquid, while the motor chamber (30) is located above a maximum level (26) of the liquid, characterized by a cooling jacket (40) surrounding the motor chamber, which has a cylindrical shape and forms an annular chamber (42) and which is in fluid connection on the one hand with the pump chamber (14) and on the other hand with the outlet connection piece (44), wherein a pressure line (20), which connects the pump chamber (14) to the cooling jacket (42), opens into the cooling jacket (42) in a first circumferential position (A) and the outlet connection piece (44) is connected to the cooling jacket (42) in a second circumferential position (B) and the first and second circumferential positions (A, B) are diametrically opposite one another.

2. The pump system according to claim 1, wherein the outlet connection piece (44) extends radially from the cooling jacket (42).

3. The pump system according to claim 1, or 2, wherein the outlet connection piece (44) is arranged at the axial end of the cooling jacket (42) opposite the pump chamber (14).

4. The pump system according to one of the preceding claims, wherein parts of the motor chamber (30) project axially beyond the cooling jacket (40) at the end facing away from the pump chamber (14).

5. The pump system according to one of the preceding claims, wherein a circumferential wall of the pump chamber (14) is formed by a plurality of ring modules (48) which are detachable from one another, and a plurality of impellers (18) are detachably held on the shaft (16).

6. The pump system according to one of the preceding claims, wherein the motor chamber (30) is closed on the side facing the pump chamber (14) by a shaft seal (46) for the shaft (16), and the shaft (16) is mounted in rolling bearings (29), all of which are located on the side of the shaft seal (46) facing away from the pump chamber.