US3039397A

US3039397A - Pump

Info

Publication number: US3039397A
Application number: US729703A
Authority: US
Inventors: Herbert F Prasse; Howard L Steele
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1958-04-21
Filing date: 1958-04-21
Publication date: 1962-06-19
Anticipated expiration: 1979-06-19

Description

H. F. PRASSE ET AL June 19, 1962 PUMP 4 Sheets-Sheet l -FiledApril 21, 1958 llllllll Q #Q @T QQ N m a N N k h 3 QInIQI Q I! A/ W Y N k .Q Q Mn he 21 2715 Herberf F P172556 June 19, 1962 H. F. PRASSE ETAL 3,039,397

PUMP

Filed April 21, 1958 4 Sheets-Sheet 2 Herberi F Prasse 1- Howard L. .Sfee/e Z7 aw 0V%H [[7 5 June 19, 1962 H. F. PRASSE ETAL 3,039,397

Filed April 21, 1958 4 Sheets-Sheet 3 Herberf F Pmsse Ho an/ L. Steele June 19, 1962 H. F. PRASSE ETAL PUMP 4 Sheets-Sheet 4 Filed April 21, 1958 Herber! F PraJSe Howard L. SZee/e M flrz s United States Patent 3,039,397 PUMP The present invention relates to improvements in pumps, and more particularly to a rotary pump which is capable of pumping liquid from a washing machine where the l1qu1d is severely oversudsed without losing suction, and also which is capable of continued dry operation without damage to the pump.

In a pump which may be used for transferring wash water in a washing machine to a drain or to a suds storage tank, heavily sudsed conditions of the wash water are often encountered. In many pump structures suitable for use with a laundering machine, an oversudsed condition will cause the pump to lose its suction, and the pump will continue to run and be locked by the soap bubbles without drawing wash water. An important feature of the present pump is its ability to remove suds from a washing machine under severely oversudsed conditions, and its ability to compress air in the' suds and convert the suds into soapy water to continue trans-ferral of the wash water.

In the transfer of washing water in a laundry machine to drain the laundry tub or to return the water to the tub from a storage tank, it is advantageous to provide a pump which can operate dry without the flow of water, without damage to the pump. Thus, the laundry machine can be operated through cycles of operation which have a fixed time period, and with varying quantities of wash water. Further, the pump can be operated with other mechanism without having to provide a clutch for stopping the pump and operating it only when a water transfor operation is performed. A feature of the invention is the provision of a pump which will operate satisfactorily for all purposes with a laundry machine, and which can operate dry over periods without damage to the pump.

Another problem encountered in pumping laundering liquids and in other pumping environments is created by abrasives and particles which are suspended in the liquid pumped. The present invention contemplates the provision of an improved pump capable of handling a liquid with a certain amount of abrasives without causing the life of the pump to :be shortened. Excessive noise is often encountered in laundry pumps, especially when mixtures of suds and liquids are pumped, and the present invention contemplates the provision of a pump which is not noisy when subjected to such operational circumstances.

Accordingly, an object of the present invention is to provide an improved rotary pump which provides the above features, and which has an improved structure so as to function in an improved manner, and be particularly advantageous for use in transferring washing liquid for laundering machines.

Another object of the invention is to provide an improved rotary pump which will effectively remove suds from a laundry machine, even under severely oversused condition, and which will compress air into the suds and convert the suds into soapy water.

Another object of the invention is to provide an improved pump which embodies the advantageous feature of both a centrigufal pump and of a 'hytor type of pump, combining the features in a new and unique manner and having increased pumping efiiciency for liquids, and which has reduced horsepower requirements.

3,939,397 Patented June 19, 1962 Another object of the invention is to provide a liquid pump which may be operated dry without damage.

A further object is to provide a pump which will handle liquid containing abrasives in suspension without shortening the operating life of the pump.

A further important object is to provide an improved pump which will handle a mixture of air and water without generating excessive noise.

Other objects and advantages will become more apparent with the teaching of the principles 'of the invention in connection with the disclosure of the preferred embodiments thereof, in the specification, claims and drawings, in which:

FIGURE 1 is a vertical sectional view taken through the axis of a pump embodying the principles of the invention;

FIGURE 2 is a sectional view taken along line II-II of FIGURE 7;

FIGURE 3 is an enlarged detailed sectional view of a portion of the end of an impeller for the pump, as also illustrated in FIGURE 5;

FIGURE 4 is an end elevational view of the impeller for the pump;

FIGURE 5 is a vertical sectional view taken along line VV of FIGURE 4, and showing a portion of the impeller in full;

FIGURE 6 is an end elevational view taken along line V*I-VI of FIGURE 1;

FIGURE 7 is an end elevational view of the inside of a portion of a housing for the pump illustrated with an end of the housing and the impeller removed; and

FIGURE 8 is a vertical sectional view taken along line VIIIVIII of FIGURE 1; and

FIGURE 9 is a sectional view, similar to FIGURE 8, taken along line VIII-V'III of FIGURE 1, with impeller blades removed to better illustrate limiting positions of the parts.

As shown in the drawings: 1

It will be understood that while reference will be made to use of the pump in a washing machine for pumping soapy water this is by Way of illustration and the pump may be used in other environments utilizing the features and advantages of the invention.

An assembled pump 10 is shown in. FIGURE 1, provided with a housing 12, which is also shown in FIG- URE 6. The housing has a body portion 13 and a base portion 18. The portion 13 has a generally circular outer wall 14 with an end wall 16, and is shown in FIGURES 1, 6 and 7. The base portion 18 closes an open end of the body portion 13 and supports the bearing for the im peller 20.

The impeller 20 is coaxially located within a central generally cylindrically shaped pump chamber 22 within the housing 12, and the impelleris shown in detail in FIGURES l, 3, 4 and 5. At one side of the pump chamber 22 is a lobe chamber 24.

The foregoing general elements include more specific details of construction, and the housing 12, is formed of the sections 13 and 18, which are secured together by threaded screws 26. The screws are passed through holes 28 in an annular outwardly extending flange 30 in the housing section 13, and are screwed into'threaded holes 32, annularly disposed adjacent the outer edge of the base portion 18 of the housing. An annular gasket ring 34 may be positioned in a groove between the housing sections to prevent leakage. The housing may be formed of a material such as Durez or Bakelite, or other plastic material, or may be formed of other materials.

The impeller 20, as illustrated in FIGURE 1, 4 and 5, is formed of rubber or the like, and has a hollow hub the hub 38 and form outwardly facing pockets 44 therebetween. At one end, the impeller blades are secured to an impeller disc or wall 46 which extends radially outwardly from the hub38.

The impeller blades extend outwardly and curve forwardly relative to the direction of movement of the impeller, as shown by arrow 48, as may be best seen in FIGURE 4. This forward curvature operates to aid in compression of soap bubbles, and turns them to liquid when the pump is pumping a soapy liquid, thereby preventing the pump from losing its suction, and insuring continued pumping movement of the liquid. The curvature of the blades in their forward direction, with the impeller turning in the direction indicated by the arrows 48, has a special relationship to the inlet and outlet ports for the pump, as will be described later in connection with FIGURES 8 and 9.

The impeller hub 38, at the end opposite the blade supporting wall 46, is provided with a plurality of axially projecting annular ridges 59, with the ridges being concentric and being radially spaced from each other to provide grooves 52, and efiecting a labyrinth seal across the end of the hub, preventing leakage between the various pockets 44 and between the blades 42.

The impeller is rotatably supported in its coaxial position within the pump chamber 22 on a rotary drive shaft 54. The shaft 54 threads into a supporting spindle 56 which is located in the center of the hub 20, for supporting and driving the hub. The spindle 56 is threaded to receive a threaded end 58 of the drive shaft 54.

The portion 18 of the housing has a hollow projecting bearing 66 with webs or struts 68 for added support on the housing. The shaft 54 has enlarged bearing portions 70 rotatably supported in the hollow bearing projection 66 of the housing. A drain opening 72 prevents the build-up of pressure in the event the liquid leaks from the pump chamber 22.

A seal, shown generally at 74, is provided at the back of the pump impeller 20 to prevent the leakage of pumped liquid. The seal includes a first annular sealing ring 76, which rotates with the pump impeller and which may be formed of ceramic or like material. Matingly and slidingly engaged with the first ring 76 is a second ring 78, which is fixed within the housing and has a surface in rotating sliding sealing engagement with the first ring 76, permitting the pump impeller to rotate and preventing the leakage of liquid from a chamber 80 behind the plate 46 of the impeller. The plate 46 prevents a direct flow of pumped liquid from passing into the chamber 80 and directly engaging the sealing rings 76 and 78.

The first sealing ring 76' is supported on a rubber mounting ring 82 which fits snugly around the shaft 54. The rubber mounting ringfits snugly against a stainless steel washer 84, which is carried with the impeller hub 20.

The second sealing ring 78 is axially pressed into sealin g engagement with the first sealing ring 76 by a conically shaped helical compression spring 86. Extending around the compression spring 86 is a conically shaped rubber cup 88, which seats against a shoulder 90 Within the bearing projection 66 of the housing, and with the shoulder 90 also providing a seat for the spring 86. The other end of the cup 88 is held against the second sealing ring 78 by the compression spring 86. The rubber cup provides a follow-up seal and moves with the second sealing ring 78 as it is forced axially into sealing engagement with the first sealing ring, or as wear occurs on the second sealing ring.

As illustrated in FIGURES l, 2, 6 and 7, liquid flows into the pumping chamber 22 through an inlet port 92. The inlet port is defined by an axially projecting hollow boss 94, which is integral with the housing section 13. The inlet port 94 is displaced from the axial center 96 of the pumping chamber 22, and is positioned so that the liquid will flow into the pockets 44 between the impeller vanes or blades generally at the time they are approaching a position where they are exposed to the lobe chamber 24. The optimum position of the inlet port relative to the vanes will be discussed in connection with FIGURES 8 and 9.

Pumped liquid is discharged through an outlet port 98. The outlet port opens axially from the pumping chamber 22, and is also radially displaced from the axial center 96 of the pumping chamber. The outlet port is also circumferentially spaced from the inlet port 92 in the direction of rotation of the impeller 20. The outlet port is defined by a hollow annular boss 100 integral with the end wall 16 of the housing portion 13 of the pump.

It will be noted from FIGURE 7 that the outlet port 98 is radially disposed a distance from the center 96 of the pumping chamber greater than the inlet port 92. As may be seen in FIGURE 7, are 102 has been swung, having the radius R to meet the outer edge of the inlet port 92. The line is pased through the outlet port 98, and it will be observed that a substantial area of the port 98 lies outside of the outermost edge of the inlet port 92. By placing the outlet outwardly from the inlet, the advantage of centrifugal pumping action is attained. While the inlet port 92 and the outlet port 98 may overlap radially, this radial overlap, as represented by the area of the outlet port 98 inside of the line 102, should be kept within permissible limits determined by the limit of the radial distance of the outlet port from the outer edge 166 of the pump chamber 22 as viewed in FIGURE 7. Thus, this distance, as shown at D, must be no less than the maximum depth of the lobe chamber, as shown at D, in order to retain the liquid seal.

The outlet port 98 is provided with an extension 194, which is created by forming a cored portion or a groove in the end wall 16 of the housing to communicate with the outlet port. This groove or channel 104 will extend the time that communication is obtained between the outlet port 98 and the pockets between the impeller blades. The construction of this port extension may be seen in detail in FIGURES 2 and 9.

The optimum locations of the various elements of the pump and the limits of structural relationship between the various parts are shown in the sectional view of PI"- URE 9 taken along line VIHVIII of FIGURE 1, and showing the pumping chamber 22 in full, and also the impeller 26 with blades removed. The inlet and outlet ports are shown in one position and construction lines indicate the permitted limits of their positions. Although reference is made to indicate impeller blades 42a and 42b, it will be understood that the description applies to any pair of adjacent blades around the impeller with a chamber 44 between them.

As illustrated in FIGURES 8 and 9, the inlet port 92 preferably overlaps the end of the impeller hub 38. This exposes at least the outer grooves 52, FIGURES 4 and 5, at the end of the hub to inlet pressure.

The pumping chamber 22 is substantially cylindrical in shape, and at one side of the chamber, the lobe chamber 24 projects therefrom. The depth of the lobe chamber 24 is shown as D.

It will be noted that the lobe chamber gradually increases in depth a it builds out from the pumping chamher, and its deepest portion 25 is directly intermediate the locations Where it starts from the pumping chamber. The points at which the lobe chamber 24 begins forming, or in other words, begins forming by expanding from the pumping chamber, may be referred to generally as the tangent points. Thus, one end of the lobe chamber will herein be referred to as T which is the tangent point at one end of the lobe chamber, and the other end of the lobe chamber will be generally herein referred to as T which is the other end of the lobechamber. The structural location of the ports will generally be defined with reference to these tangent points T and T A construction line 108 is drawn through the diameter of the pump chamber in FIGURE 9, equidistant from the tangent points T and T The inlet port is shown preferably located with its radial center line passing through the tangent point T which is 30 in advance of the diameter line 108. We have found that the inlet port preferably is located no further in advance of the first tangent point T than where its leading or opening edge 110, in the direction of rotation of the impeller, is 40 in advance of the tangent point T The trailing or closing edge 113 of the inlet port, in the direction of rotation of the impeller, should be no further from the first tangent point T than 40. Thus, as illustrated in FIGURE 8, the leading edge 110 of the inlet port 92 preferably is no further in advance of the tangent point T than indicated by the line 112, which is 40 in advance of the tangent point T The trailing edge 113 of the inlet port 92 preferably is no further from the tangent point T than the line 114, which trails T by 40.

In referring to leading and trailing directions herein, it will be understood that these are relative to the direction of rotation of the impeller.

Only two blades or vanes are shown in FIGURE 9 for purposes of illustration of the flow of liquid with respect to each of the pockets 44 between each pair of adjacent blades. The leading blade is designated as 42a, while the trailing blade is designated as 42b.

Opening of the port 92 will occur just as the trailing edge of the blade 42a passes the leading edge 110 of the port 92.

In further limitation of the location of the inlet port, as shown in FIGURE 9, the inlet port 92 should open no later than when the tip 116 of the leading blade 42a reaches the tangent point T The inlet port preferably opens as the leading edge 109 of the blade 42a is 20 in advance of the tangent point T i.e., at line 117.

The port closes when the leading edge 119 of the trailing blade 42b for the pocket 44 passes the trailing edge or closing edge 113 of the port 92.

As a further limitation of the position of the inlet port 92, the port preferably closes no later than when the blade 42b reaches a location wherein its tip 135 is 60 past the tangent point T as indicated by line 124. The inlet 92 must close by the time the leading tip 116 of the leading blade 42a reaches the point 25 of maximum lobe depth.

It will be understood that the foregoing limitations are determined by the size of the inlet port as well as its position and by the curvature of the impeller blades and other dimensional factors. Accordingly, the locations of the elements are selected in accordance with the prescribed limitations.

As to the outlet port 98, the trailing or closing edge 134 of the port preferably is positioned no further from the tangent point T than the position shown in FIGURE 9. The port 98 has its trailing or closing edge 134, ahead of the tangent line T as indicated by the radial line 136. The outlet port should be positioned with its leading or opening edge 130 spaced no further from the closing edge 134 than 70, as indicated by the line 132.

The outlet port 98 closes when the leading edge 119 of the trailing blade 42b passes the closing end 134 of the outlet port 98. The outlet port 98 must be positioned so that it closes not before the tip 135 of the impeller blade 42b reaches the tangent point T In operation of the pump, liquid is drawn in through the inlet port 92 to enter the pockets 44 between the impeller blades 42 on the impeller 20. The liquid is forced outwardly by the centrifugal action of the impeller, and gas bubbles are compressed by the forwardly curved blades 42 on the impeller. The pockets 44 between the impeller blades communicate with the lobe chamber 24, which is located at one side of the pump chamber 22. The liquid is discharged axially through the discharge or outlet port 98, which is circumferentially spaced from the inlet port 92 in the intake port 92. The

pump will continue operation compressing pockets of air such as which occur if a soapy liquid is pumped, and the soap bubbles will be compressed and turned into liquid. Further, if a how of liquid ceases, the pump can continue operation in a dry stage, without damage. The pump is also of such a nature that abrasives contained in the liquid will not damage the pump.

-We have, in the drawings and specification, presented a detailed disclosure of the preferred embodiments of our invention, and it is to be understood that we do not intend to limit the invention to the specific forms disclosed, but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by our invention.

We claim as our invention:

1. A pump assembly comprising in combination a housing having first and second segmental cylindrical chamber defining inner surfaces in radial overlapped relation with the axial centers of said surfaces spaced from each other, said housing also having end walls closing said chamber, an impeller having impeller blades with spaces therebetween mounted in said chamber coaxial with said first inner surface with the portion of the housing chamber occupied by the impeller forming a pump chamber and the portion at the side of the impeller bounded by the second cylindrical surface forming a lobe chamber, the points of intersection of said cylindrical surfaces forming first and second tangent points with said first tangent point located where the impeller first becomes exposed to the lobe chamber during rotation, means rotatably supporting the impeller in the pump chamber, an outlet port in an end wall of the chamber, and an inlet port in an end wall of the chamber, said ports displaced from the axis of the pump chamber and circumferentially displaced from each other and communicating with the spaces between the impeller blades, said inlet port having a leading edge relative to the direction of impeller rotation with the leading edge in advance of the first tangent point with the angle of advance being no greater than 40.

2. A pump assembly comprising in combination a housing having an outer wall and end walls forming a chamber therein, an impeller having impeller blades with spaces therebetween mounted in said chamber with the ends of the blades sufficiently close to the housing end walls so that fluid will not by-pass the blade ends, said outer wall having a first fragmentary cylindrical portion with its center coaxial with the impeller and a second fragmentary cylindrical portion with its center radially displaced from the center of the first portion, the portion of the housing chamber occupied by the impeller defining a pump chamber and the portion of the housing chamber between the impeller and said second wall portion defining a lobe chamber, means rrotatably supporting the impeller in the pump chamber, an outlet port in an end Wall of the housing chamber, an inlet port in an end wall of the housing chamber, said ports radially displaced from the axis of the pump chamber and circumferentially displaced from each other and communicating with the spaces between the impeller blades, and a hub member centered on the end of the impeller having an end in close proximity to the end wall of the housing having the inlet port and having a plurality of annular ridges 0n the end coaxial with the impeller and being sufiiciently close to the housing end wall for each ridge to form a seal, at least the outer of said ridge positioned radially outwardly of the radially innermost limit of said inlet port so that the area of the hub member radially inwardly of said outermost ridge is in communication with the inlet port with leakage fluid passing radially inwardly over the outermost of said ridges flowing to the inlet port, said outlet port positioned out of communication with the areas between the ridges of said hub member.

3. A pump assembly comprising in combination a housing having an outer wall and end walls forming a chamber therein, an impeller having impeller blades with spaces therebetween mounted in said chamber with the ends of the blades sufliciently close to the housing end walls so that fluid will not bypass the blade ends, said outer Wall having a first fragmentary cylindrical portion with its center coaxial with the impeller and a second fragmentary cylindrical portion with its center radially displaced from the center of the first portion, the portion of the housing chamber occupied by the impeller defining a pump chamber and the portion of the housing chamber between the impeller and said second Wall portion defining a lobe chamber, means for rotatably supporting the impeller in the pump chamber, an inlet port in an end wall of the housing chamber, and an outlet port in an end wall of the housing chamber, said ports displaced radially from the axis of the pump chamber and circumferentially displaced from each other and communicating with the spaces between the impeller blades, the radially outermost edge of said outlet port spaced radially inwardly from the radially outer ends of the impeller blades a distance equal at least the maximum radial depth of the lobe chamber so that a liquid ring seal is maintained "at the outer edge of the impeller for continuous pumping action, the center of said outlet port positioned at a greater radial distance from the axial center of the pump chamber than the center of the inlet port and the radial inner extremity of the outlet port positioned a smaller radial distance from the axial center of the pump chamber than the radial outer extremity of the inlet port so that said ports are in overlapping position.

4. A pump assembly comprising in combination a housing having an outer wall and end Walls forming a chamber therein, an impeller having impeller blades With spaces therebetween mounted in said chamber with the ends of the blades sufliciently close to the housing end 3 Walls so that fluid will not by-pass the blade ends, said outer wall having a first fragmentary cylindrical portion with its center coaxial with the impeller and a second fragmentary cylindrical portion with its center radially displaced from the center of the first portion, the portion of the housing chamber occupied by the impeller defining a pump chamber and the portion of the housing chamber between the impeller and said second wall portion defining a lobe chamber, means rotatably supporting the impeller in the pump chamber, an outlet port in an end wall of the housing chamber, and an inlet port in an end wall of the housing chamber, said ports displaced radially from the axis of the pump chamber and circumferentially displaced from each other and communicating with the spaces between the impeller blades, the center of said outlet port positioned at a greater radial distance from the center of the pump chamber than the center of the inlet port and the radial inner extremity of the outlet port positioned a smaller radial distance from the axial center of the pump chamber than the radial outer extremity of the inlet port so that said ports are in overlapping position.

References Cited in the file of this patent UNITED STATES PATENTS 1,720,458 Wendell July 9, 1929 1,904,321 Nash Apr. 18, 1933 2,533,399 Sadler et a1 Dec. 12, 1950 2,604,852 Baker July 29, 1952 2,649,052 Weyer Aug. 18, 1953 2,696,789 Fabig Dec. 14, 1954 FOREIGN PATENTS 421,458 Great Britain Dec. 20, 1934 421,964 Great Britain Jan. 2, 1935 698,485 Germany Nov. 11, 1940