US3186345A

US3186345A - Means for preventing or limiting interchange of liquids between communicating vessels

Info

Publication number: US3186345A
Application number: US275129A
Authority: US
Inventors: Ivanoff Victor
Original assignee: Hayward Tyler and Co Ltd
Current assignee: Hayward Tyler and Co Ltd
Priority date: 1962-04-26
Filing date: 1963-04-23
Publication date: 1965-06-01
Anticipated expiration: 1982-06-01
Also published as: GB993668A; CH406857A; DE1528865A1

Description

June 1, 1965 v. lVANOFF 3,135,345

MEANS FOR PREVENTING 0R LIMITING INTERCHANGE OF LIQUIDS BETWEEN COMMUNICATING vEssELs Filed April 25, 1963 United States Patent 3 186 345 MEANS FOR PREVENTING 0R LIMITING INTER- CHANGE OF LIQUIDS BETWEEN COMMUNI- CATING VESSELS Victor Ivanoif, Harpenden, England, assignor to Hayward- This invention relates to submersible electric motor and pump units of the type, hereinafter referred to as the type defined, in which the motor and pump are enclosed in a casing forming an upper, motor chamber, and a lower, pump chamber, the two chambers being joined by a relatively narrow neck portion through which extends, with clearance, a shaft carrying the motor rotor at its upper end, and the pump rotor at its lower end, the liquid in the pump chamber having access to the motor chamber by Way of the annular clearance gap between the shaft and the neck of the casing.

When a unit of the type defined is used for pumping liquids at high temperature, the pump chamber is filled with hot liquid which tends to be carried by convection currents through the annular gap up to the motor chamber. Apart from the danger of over heating of the motor which is involved, the heat losses can, in large installations, amount to tens of horsepower. To prevent over heating of the motor it is known to provide an external coiling system, hot liquid being tapped off from the lower end of the motor chamber, cooled, and passed back to the casing at the upper end of the motor chamber. The circulation of liquid through the external cooling system is forced by an auxiliary impeller carried at the upper end of the motor shaft. The unit may, however, be required for hot stand-by duty, that is to say it may be immersed in the liquid, so that the liquid fills the casing, in readiness for immediate use in the event of the failure of another pump. In these circumstances the motor shaft is stationary and so the auxiliary impeller is not operative to provide a forced circulation of liquid through the external cooling system, and the liquid in the motor chamber tends to become heated by convection.

The present invention provides means for limiting the interchange by convection of the relatively hot liquid in the lower, pump chamber and the relatively cool liquid in the upper, motor chamber.

In accordance with the present invention there is provided a submersible electric motor pump unit of the type herein defined, in which there is provided, at one end of the annular passage, a liquid trap or labyrinth including a downwardly directed wall surrounding the mouth of the passage, the arrangement being such that in order to pass from the lower chamber to the upper chamber through the annular passage, liquid must pass downwardly below the lower edge of the said wall.

One form of submersible electric motor pump unit in accordance with the invention will now be described, with reference to the accompanying drawing, which is an elevation, partly in axial section, of the unit.

The electric motor pump unit shown in the drawing comprises a casing in three parts, an upper portion 1 defining a motor chamber, a lower portion 2 defining a pump chamber and a relatively narrow neck portion 3 connecting the upper and lower portions. A shaft 4, common to the motor and the pump, carries the motor rotor at its upper end, for co-operation with stator windings mounted within the upper casing portion 1. The shaft extends with clearance through the neck portion 3, so that an annular passage 5 is defined between the shaft and the neck, and at its lower end, within the pump chamber,

ice

the shaft carries a pump impeller 6. The pump chamber is provided with the usual inlet 7 and outlet 8.

Just beyond the upper end of the annular passage 5, there is secured to the shaft 4, in sealed relation therewith, a labyrinth comprising a generally bell shaped member 11 concentric with and surrounding the shaft, with its mouth facing the adjacent upper end of the passage 5. A tubular baflle 12 is mounted at the upper end of the annular passage 5 so as to form an upward extension thereof, and extends into the bell although spaced therefrom, with its upper edge at a higher level than the lower edge of the bell.

With this arrangement, hot liquid rising through the neck of the casing passes into a trapped space within the bell 11, and to escape from this space must first pass downwardly below the lower edge of the bell, through the cooler liquid surrounding the bell and the bafile 12.

This trap or labyrinth arrangement can be inverted by providing a second labyrinth comprising an inverted bell 13 on the shaft 4 adjacent the lower end of the passage 5, and a downwardly extending tubular baffle 14 at the lower end of the passage. For hot liquid to pass from the pump chamber to the annular passage, it must pass below the lower edge of the baffle, through the relatively cool liquid trapped within the bell.

In order to inhibit heat transference by conduction through the bells 11, 13, the tubular baffles 12, 14 and the shaft, all of which are of metal,

layers

11A, 13A, 12A and 14A, of heat insulating material, such as impregnated asbestos, are provided on appropriate surfaces of the bells and the bafiles, respectively. The layers are held in place by layers of metal cladding 11B, 13B, 12B

and 14B, respectively.

It will be apparent to those skilled in the art that the liquid trap arrangements described above can be provided at either the lower end or the upper end of the annular passage 5, but they are preferably provided at both ends, as described and illustrated.

What is claimed is:

1. A submersible electric motor and pump assemblage for pumping liquid, said assemblage comprising a housing .including a pump chamber, a motor chamber and a tubular neck portion joining the pump chamber and the motor chamber, a rotary pump within the pump chamber and an electric motor within the motor chamber, said motor having a drive shaft extending through said neck portion -with clearance to define an annular passage connecting the two chambers and coupled to the pump for rotating the same, said pump chamber having an inlet and an outlet for liquid to be pumped, the liquid flooding both chambers and the annular passage in the submersed condition of the assemblage, and a labyrinth means adjacent to one end of said annular passage, said labyrinth means inhibiting an upward flow of convection currents from the pump chamber towards the motor chamber by constraining said current to flow along a tortuous path exposing the same to a cooling action by liquid in the motor chamber prior to entering said motor chamber.

2. A submersible electric motor and pump assemblage for pumping liquid, said assemblage comprising a housing including a pump chamber, a motor chamber and a tubular neck portion joining the pump chamber and the motor chamber, a rotary pump within the pump chamber and an electric motor within the motor chamber, said motor having a drive shaft extending through said neck portion with clearance to define an annular passage connecting the two chambers and coupled to the pump for rotating the same, said pump chamber having an inlet and an outlet for liquid to be pumped, the liquid flooding both chambers and the annular passage in the submersed condition of the assemblage, and a labyrinth means adjacent to one end of said annular passage, said labyrinth means including a bell-shaped member disposed in the motor chamber adjacent to the respective end of the annular passage in lengthwise alignment therewith, said bell-shaped member being surrounded by' and filled with liquid in the motor chamber, the open side of the bell-shaped member facing towards said passage to inhibit an upward flow of convection currents by guiding said currents through said passage at least partly into the bell-shaped member and then around the free rim thereof, thereby exposing convection currents flowing from the pump chamber towards the motor chamber to a cooling action by the liquid in the motor chamber prior to entering said motor chamber.

3. A submersible electric motor and pump assemblage for pumping liquid, said assemblage comprising a housing including a pump chamber, a motor chamber and a tubular neck portion joining the pump chamber and the motor chamber, a rotary pump within the pump chamber and an electric motor within the motor chamber, said motor having a drive shaft extending through said neck portion with clearance to define an annular passage connecting the two chambers and coupled to the pump for rotating the same, said pump chamber having an inlet and an outlet for liquid to be pumped, the liquid flooding both chambers and the annular passage in the submersed condition of the assemblage, and a labyrinth means adjacent to one end of said annular passage, said labyrinth means including a bell-shaped member disposed in the motor chamber coaxial with the said shaft sealed thereto, the open side of said bell-shaped member facing toward said annular passage, said bell-shaped member being surrounded by and filled with liquid in the motor chamber, and a tubular bafi'le forming an extension of said annular passage within the motor chamber and extending into the open side of the bell-shaped member spaced from the side and bottom walls thereof to form a tortuous path inhibiting an upward flow of convection currents emerging from said one end of the annular passage by exposing such currents to a cooling action by liquid in the motor chamber prior to entering the same.

4. An assemblage according to claim 2 wherein wall surfaces of said bell-shaped member are lined with a heatinsulating material to inhibit heat transfer by conduction through said lined wall surfaces.

5. A submersible electric motor and pump assemblage for pumping liquid, said assemblage comprising a housing including a pump chamber, a motor chamber and a tubular neck portion joining the pump chamber and the motor chamber, a rotary pump within the pump chamber and an electric motor within the motor chamber, said motor having a drive shaft extending through said neck portion with clearance to define an annular passage connecting 4 the two chambers and coupled to the pump for rotating the same, said pump chamber having an inlet and an outlet for liquid to be pumped, the liquid flooding both chambers and the annular passage in the submersed condition of the assemblage, and a labyrinth means in each chamber adjacent to the respective end of said annular passage, each of said labyrinth means inhibiting an upward flow of convection currents from one chamber to the other through said passage by constraining said currents to flow along a tortuous path prior to entering and leaving the respective chamber.

6. A submersible electric motor and pump assemblage for pumping liquid, said assemblage comprising a housing including a pump chamber, a motor chamber and a tubular neck portion joining the pump chamber and the motor chamber, a rotary pump within the pumpchamber and an electric motor within the motor chamber, said motor having a drive shaft extending through said neck portion with clearance to define an annular passage connecting the two chambers and coupled to the pump for rotating the same, said pump chamber having an inlet and an outlet for liquid to be pumped, the liquid flooding both chambers and the annular passage in the submersed condition of the assemblage, and a labyrinth means in each chamber adjacent to the respective end of said annular passage, each of said labyrinth means including a bellshaped member disposed in the respective chamber coaxial with said shaft sealed thereto, the open side of each of said bell-shaped members facing toward said annular passage, each of said bell-shaped members being surrounded by and filled with liquid in therespective chamber, and a tubular bafile forming an extension of said annular passage within the respective chamber and extending into the open side of the respective bell-shaped member spaced from the side and bottom walls thereof to form a tortuous path adjacent to each end of the annular passage inhibiting an upward flow of convection currents from one chamber to the other through said passage by constraining said currents to flow along said tortuous path prior to entering and leaving the respective chamber.

References (Iited by the Examiner UNITED STATES PATENTS 1,346,924 7/20 VVilfley 103-411 2,381,823 8/45 La Bour 163-111 2,677,328 5/54 Vitek 103l1l LAURENCE V. EFNER, Primary Examiner.

ROBERT M. WALKER; Examiner.

Claims

1. A SUBMERSIBLE ELECTRIC MOTOR AND PUMP ASSEMBLAGE FOR PUMPING LIQUID, SAID ASSEMBLAGE COMPRISING A HOUSING INCLUDING A PUMP CHAMBER, A MOTOR CHAMBER AND A TUBULAR NECK PORTION JOINING THE PUMP CHAMBER AND THE MOTOR CHAMBER, A ROTARY PUMP WITHIN THE PUMP CHAMBER AND AN ELECTRIC MOTOR WITHIN THE MOTOR CHAMBER, SAID MOTOR HAVING A DRIVE SHAFT EXTENDING THROUGH SAID NECK PORTION WITH CLEARANCE TO DEFINE AN ANNULAR PASSAGE CONNECTING THE TWO CHAMBERS AND COUPLED TO THE PUMP FOR ROTATING THE SAME, SAID PUMP CHAMBER HAVING AN INLET AND AN OUTLET FOR LIQUID TO BE PUMPED, THE LIQUID FLOODING BOTH CHAMBERS AND THE ANNULAR PASSAGE IN THE SUBMERSED CONDITION OF THE ASSEMBLAGE, AND A LABYRINTH MEANS ADJACENT TO ONE END OF SAID ANNULAR PASSAGE, SAID LABYRINTH MEANS INHIBITING AN UPWARD FLOW OF CONVECTION CURRENTS FROM THE PUMP CHAMBER TOWARDS THE MOTOR CHAMBER BY CONSTRAINING SAID CURRENT TO FLOW ALONG A TORTUOUS PATH EXPOSING THE SAME TO A COOLING ACTION BY LIQUID IN THE MOTOR CHAMBER PRIOR TO ENTERING SAID MOTOR CHAMBER.