US 3826589 A
A pump construction having a housing composed of a pair of plastic housing sections. The abutting ends of the housing sections are provided with mating flanges which are joined together by a clamping ring to provide a continuous peripheral connection for the housing sections. To compensate for deflection in the plastic housing sections under operating pressure, a sliding axial connection is provided between the inlet of the diffuser of the pump and one of the housing sections. Heat is dissipated from the area of the drive shaft seal by means of a metallic shield having a base secured to one of the plastic housing sections, and the body of the shield extends outwardly within the pumping chamber in spaced relation to the seal and to the housing section.
Claims available in
Description (OCR text may contain errors)
United States Patent Frank et a1.
45] July 30, 1974 PLASTIC PUMP CONSTRUCTION Inventors: Raymond W. Frank; William M. Kralovec, both of Delavan, Wis.
Assignee: Sta-Rite Industries, Inc., Delavan,
Filed: June 22, 1972 Appl. No: 265,347
U.S. Cl. 415/170 A, 415/201, 415/214, 277/22 Int. Cl. F04d 29/10, F04d 29/40 Field of Search 277/22,.32, 134;415/53, 415/211, 201, 170 A, 124, 175, I76, 178, 214; 417/82, 83
References Cited UNITED STATES PATENTS 11/1952 Mann 417/82 11/1954 Price 415/211 5/1957 Gudmundscn... 415/53 7/1958 Janetz 415/170 A 4/1960 Conery et a1. I. 415/211 8/1964 Weis 415/124 9/1970 FOREIGN PATENTS OR APPLICATIONS 8/1966 Great Britain ....277/22 Goldberg 277/32 OTHER PUBLICATIONS Publication DuPont Zytel 3 pages, 1954, E. I. DuPont De Nemours & Co.
Primary Examiner-Henry F. Radluazo Attorney, Agent, or FirmAndrus, Sceales, Starke and Sawall ABSTRACT A pump construction having a housing composed of a pair of plastic housing sections. The abutting ends of p the housing sections are provided with mating flanges one of the plastic housing sections, and the bodyof the shield extends outwardly within the pumping chamber in spaced relation to the seal and to the housing section.
9 Claims, 3 Drawing Figures PATENTEB mama sum 2 (IF 2 BACKGROUND OF THE INVENTION The conventional centrifugal pump, as used in water systems or chemical processing industries, includes a housing or casing composed of cast iron housing section which are generally joined together by bolts. Attempts have been made in the past to fabricate the housing sections of plastic materials, for plastic has better corrosion resistance and can be molded in more attractive designs, but such attempts have not met with success. Problems have been countered due to the distortion of the plastic housing sections under pressure, thereby producing stresses and causing failure or leakage at the bolted joints between the housing sections.
Further problems have arisen in situations where the pump is operated with a loss of prime, or under other conditions where the pumping chamber is not filled with water. In such situations, a rapid build-up of heat may occur due to the insulating effect of the plastic material, and this heat build-up can cause deterioration and failure of the drive shaft seal, resulting in leakage from the pump.
SUMMARY OF THE INVENTION The present invention relates to a pump construction having a housing formed of plastic housing sections which overcomes the problems associated with prior attempts to utilize a plastic housing or casing. More specifically, the pump housing is composed of a pair of plastic housing sections having abutting edges provided with mating flanges that are joined together by a clamping ring. The clamping ring provides a continuous peripheral connection for the two plastic housing sections.
To compensate for possible delfection in the plastic housing sections due to the pressure of the pumped liquid, the diffuser is rigidly secured to one of the plastic housing sections and a sliding axial connection is provided between the inlet of the diffuser and the other housing section. The sliding connection permits that housing section to deflect under pressure and move relative to the diffuser without setting up undesirable stress concentrations in the plastic material.
To dissipate heat from the area of the drive shaft seal, a generally conical, metallic shield is secured to one of the plastic housing sections and extends outwardly within the pumping chamber in spaced relation to the seal. Under conditions where the pump is operating with a loss of prime, or under other conditions where the pumping chamber is not filled with liquid, the metallic heat shield, by extending downwardly into the liquid trapped within the pumping chamber, will act to dissipate heat from the area of the seal to the liquid.
The pump construction of the invention, by utilizing plastic material for the housing, provides better corrosion. resistance for the housing. As the housing sections can be readily molded to the desired shape, a more attractive apperance can be obtained, as well as minimizing machining of the components. As a further advan-' tage, the plastic material, being electrically nonconductive, provides a safer unit.
The use of the clamping ring provides uniform clamping pressure at the joint between the housing sections and eliminates the problem of leakage even though the housing sections may deflect slightly under operating pressures.
The metallic heat shield acts to dissipate heat from the area of the seal thereby preventing an undue build up of temperature in the seal which could result in a deterioration of the sealing element.
Other objects and advantages will appear in the course of the following descriptions.
DESCRIPTION OF THE DRAWINGS The drawings illustrate the best mode presently contemplated of carrying out the invention.
In the drawings:
FIG. 1 is a vertical section of the pump construction of the invention;
FIG. 2 is a transverse section taken along line 2-2 of FIG. 1; and
FIG. 3 is a perspective view of the heat shield.
DESCRIPTION OF THE PREFERRED EMBODIMENT The drawings illustrate a deep well pump for a water system constructed in accordance with the invention. The pump includes a pair of housing sections 1 and 2 which are formed of a high strength plastic material having high heat deflection characteristics. It has been found that glass filled DuPont Brand Zytel 612 nylon is particularly satisfactory for fabricating the housing sections 1 and 2.
Housing section 1 is secured to the motor housing 3 by a series of bolts 4, and the abutting edges of the housing sections 1 and 2 are provided with outwardly extending mating flanges 5 and 6. The flange 5 of housing section 1 is formed with a circumferential groove which receives an O-ring seal 7.
The mating flanges 5 and 6 are joined together by a clamping ring 8. As shown in FIG. 2, the clamping ring 8 includes an outer circular band 9 and a pair of inclined sidewalls 10 extend downwardly and outwardly from the band and are adapted to engage the sides of the respective flanges 5 and 6. The band 9 is tightened by means of a conventional turn bolt 11, or T bolt to thereby draw the flanges 5 and 6 tightly together and provide a continuous seal around the entire periphery of the pump housing. 7
A motor drive shaft 12 extends through an opening in the housing section 1 and is threaded within the hub 13 of an impeller 14. The water or other pumped liquid is drawn into the impeller through an inlet 15 which is journalled for rotation within the cylindrical neck 16 of a diffuser 17 by means of a bushing 18.
The diffuser 17 is provided with a series of curved vanes 19 which define a series of passages through which the pumped liquid flows after being discharged from the impeller. The diffuser 17 is integrally connected to the pump housing 1 by a. series of screws 20 which extend through the vanes 19 and are threaded into the housing section 1.
Water or other liquid is drawn into the pump through an inlet 21 formed in the housing section 2, and the inlet 21 is bordered by a cylindrical section 22, the end of which is disposed concentrically around the neck 16 of the diffuser. An O-ring seal 23 is located in a peripheral groove in the diffuser neck 16 and provides a seal between the cylindrical section 22 of the housing section 2 and the neck of the diffuser. With this construction, the diffuser 17 is rigidly attached to the housing section 1, but is connected to the housing section 2 through a movable sealed connection. More specifically. the cylindrical section 22 can move axially relative to the diffuser neck 16 and this permits proper assembly with greater dimensional variations in parts and also effective sealing when the plastic housing section deflects during pump operation.
The housing sections 1 and 2, in combination, define a pumping chamber 24 and an outlet 25 is provided in the housing section 2 for delivery of a portion of the pumped liquid to the jet assembly which is located in the well. The water being discharged through the jet assembly will act as the driving force to force water up wardly from the well and into the inlet 21 of the pump.
The deep well pump also is provided with a regulating valve 26 which is adapted to provide a restriction for the outlet. opening 27 in the wall 28 of housing section 2. To provide an adjustment for the position of valve 26, the valve stem 27 is threaded within a plug 30, which in turn is threaded within an opening in the housing section 2, and the outer end of the stem receives a nut 31. By loosening the nut, the stemcan be rotated to thereby adjust the position of the valve 26 with respect to the opening 27 to permit a greater or lesser quantity of the pumped liquid from the pumping chamber to pass to the outlet 32.
The adjustment of the valve 26 provides a means for varying the proportion of the water or pumped liquid which is discharged through the outlet 25 to the jet and through the outlet 32 to the pressure tank or servicelines.
A conventional pressure gauge 33 can be attached to the housing section 1 to provide an indication of the pressure in the pumping chamber. In addition, a line 34 is connected within an opening in the housing section 2 and is connected to a conventional pressure switch which acts to operate the motor when the pressure falls below a preset value.
The housing section 2 is also provided with a drain cock 35 through which water or other liquid can be drained from the pump.
To prevent leakage of the pumped liquid along the drive shaft 12, a conventional seal assembly 36 is provided. The seal assembly 36 includes a rotatable sealing section which is attached to the drive shaft 12 and comprising an axially movable carbon insert 37, a resilient sealing ring 38 and an expandable bellows 39 which connects the insert 37 and ring 38. In addition, the seal assembly 36 includes a non-rotating section that is carried by the pump housing 1, and includes a ceramic insert 40, against which the insert 37 rides, and a sealing ring 41 which is mounted within a recess in housing section 1 and within which the ceramic insert is press fitted.
Under certain conditions when the pumping chamber 24 is not filled with water, rotation of the drive shaft 12 will cause a build-up in temperature in the seal assembly 36. For example, in a situation where there is a loss of prime, the water trapped in the pumping chamber 24 will be at the level indicated by 42, so that the seal assembly 36 will be completely out of contact with the water. If the drive shaft operates under these conditions, a build-up of temperature will occur in the seal. With a pump having a cast iron housing, the temperature in the seal may build up to a value of 2lOto 220F after 90 minutes of such operation, but with a plastic housing the temperature in the seal area may reach 285F in 30 minutes due to the insulating effect of the plastic material. This high temperature build-up in the seal can cause decomposition or failure of the sealing elements and leakage along the drive shaft.
A build-up of temperature may also occur in the seal area in a situation where the pressure switch may malfunction causing the impeller to rotate continuously although there is no call for water. This can cause the temperature of the water within the pumping chamber to build up to a point where it can cause failure of the seal.
In accordance with the invention, heat build-up in the area of the seal assembly 36 is prevented by means of a metallic heat shield 43 which is secured to the housing section 1 and extends outwardly in spaced relation to the seal assembly. The shield 43 is formed of a metallic material having a high thermal conductivity, such as copper, and has an annular base section 44 that is secured between sealing ring 41 and the housing section 1. Shield 43 also includes an outwardly flared or frustoconical body 45 that extends outwardly from base 44. As best illustrated in FIG. 1, the body 45 is located in spaced relation to both the inner surface of the housing section 1 and the seal assembly 36 and has a length such that the end of the body section is located beneath the level of the water line 42. This insures that in the event prime is lost and the water drains from the chamber 24 to the level of the water line 42, the outer portion of the body 45 of shield 43 will be located beneath the water level. In this situation, if the impeller is rotated and heat builds up in the seal area, the heat will be dissipated through the shield and into the water trapped in the lower portion of the pumping chamber, thus preventing failure of the shaft seal.
The particular shape or configuration of the shield is not critical, but at least a portion of the shield should extend down beneath the water line 42 so that it will be immersed in the water trapped in the lower portion of the chamber 24 under conditions of loss of prime. Moreover, the shield can be a solid'member or can be provided with holes or perforations. While the seal is shown as attached to the non-rotating housing section 1, it is contemplated that under certain circumstances the shield could be attached to the rotating elements, although this may not be as practical due to the fact that the shield would have to be dynamically balanced and accurately contoured so that it would not contact non-rotating elements as it rotated.
The clamping ring 8 cooperates with the sliding connection between the diffuser neck 16 and the cylindrical section 22 of the housing section to provide a structure which prevents stress concentrations during pressurized conditions, as well as maintaining a positive and uniform seal over the entire periphery of the two housing sections 1 and 2. Moreover, the clamping ring 8 enables the housing sections to be fabricated with less critical tolerances and yet provides a positive seal regardless of any deflection which may occur in the sections 1 and 2.
Moreover, in the event that there may be manufacturing mis-alignments or irregularities between the diffuser neck 16 and the cylindrical section 22 of housing section 2, the clamping ring will not force the elements into alignment, but instead will compensate for any such misalignment and thereby prevent stress concentrations from being set up in the housing sections.
1. A pump construction, comprising a pump housing including a pair of plastic housing sections which define a pumping chamber, said housing sections being provided with outwardly extending mating flanges, an impeller disposed within the pumping chamber and hav ing an axial inlet for drawing liquid into the impeller, drive means for rotating the impeller, means located within the pumping chamber and connected to a first of said housing sections and having a generally cylindrical section disposed in communication with the inlet of the impeller, the second of said housing sections having a second generally cylindrical section defining a liquid inlet disposed in communication with said first cylindrical section and disposed concentrically of said first cylindrical section and said sections being in over-laping relation sealing means located between said first and second over-laping cylindrical sections, said sealing means disposed to prevent flow of the pumped liquid between said cylindrical sections but permitting relative axial movement between said cylindrical sections, a clamping ring engaged with said flanges for clamping said housing sections together, said clamping ring being in substantially continuous engagement with the entire periphery of said flanges and a metallic heat dissipating member located in the pumping chamber and having a first end disposed adjacent said sealing means and having a second end freely disposed within said pumping chamber, opposite surfaces of said heat dissipating member being exposed to the liquid in said pumping chamber whereby said heat dissipating member acts to dissipate heat from the sealing means.
2. The pump construction of claim 1, wherein said first named means connected to the first housing section comprises a diffuser, and said pump includes means for fixedly connecting said diffuser to the first of said housing sections.
3. The pump construction of claim 2, wherein the second cylindrical section is disposed radially outward of said first cylindrical section.
4. The pump construction of claim 2, wherein said drive means comprises a drive shaft that extends through an opening in the first housing section, and sealing means for sealing the shaft with respect to the first housing section.
5. A pump construction, comprising a housing defining a pumping chamber and including a plastic housing section bordering said pumping chamber, drive means including a drive shaft extending through an opening in said housing section, an impeller disposed within the pumping chamber and spaced from said housing section, seal means for preventing leakage of the pumped liquid along the drive shaft and disposed between the impeller and said housing section, and a metallic heat dissipating member located in the pumping chamber and having at least a portion disposed in radially outward spaced relation to the seal means, said heat dissipating member includes a base secured to the housing section, and said portion comprises a frustoconical wall flaring outwardly from the base in a direction toward the impeller and disposed in spaced relation to both said seal means and said housing section, said heat dissipating member acting to dissipate heat from the seal means.
6. A pump construction, comprising a housing defining a pumping chamber and including a plastic housing section bordering said chamber, drive means including a horizontal drive shaft extending through an opening in said housing section, an impeller disposed within the pumping chamber and connected to said shaft, said impeller including an inlet opening having a generally horizontal axis for supplying liquid to the impeller, said inlet opening being spaced above the bottom of said pumping chamber, seal means for preventing leakage of the pump liquid along the drive shaft and disposed between the impeller and said housing section, and a metallic heat dissipating member disposed within the pumping chamber between the impeller and said housing member, said seal means including a first nonrotating seal section connected to the plastic housing section and a second rotating seal section connected to said drive shaft, said heat dissipating member having a base portion connected to the first seal section and having a body portion extending from the base portion in a direction toward the impeller, said body portion being located in radially outward spaced relation to the second seal section and terminating in a free unattached end, a portion of said end extending downwardly to a level beneath the lower extremity of said inlet opening.
7. The pump construction of claim 6, wherein the body portion has a generally conical shape and flares outwardly from said base portion.
8. The pump construction of claim 6, wherein the base portion has a central opening to receive the shaft.
toward the impeller from the seal means.