US3560004A

US3560004A - Shaft seal having passage for heat-transfer fluid

Info

Publication number: US3560004A
Application number: US809692A
Authority: US
Inventors: Philip F Donley; Mervil D Chapman
Original assignee: Ernest F Donley and Sons Inc
Current assignee: Ernest F Donley and Sons Inc
Priority date: 1969-03-24
Filing date: 1969-03-24
Publication date: 1971-02-02
Anticipated expiration: 1988-02-02

Abstract

A sealing system for a rotatable shaft, adapted to extend through a wall member or the like, wherein seal means disposed about the shaft and effective to form an essentially fluidtight enclosure between the shaft and wall member also includes a heattransfer system positioned inwardly of the seal relative to the shaft to regulate the environmental temperature and particularly that of the seal. The heat-transfer system comprises a continuous passage of two segments of travel which are preferably consecutive. Each segment extends substantially axially of the shaft and performs a heat-transfer function. One of these segments lies along and outside of the shaft to contact it directly with the heat-transfer fluid.

Description

United States Patent 1,876,520 9/1932 Newkirk etal.

lnventors Philip F. Donley Shaker Heights; Mervil D. Chapman, South Euclid, Ohio Appl. No. 809,692 Filed Mar. 24, 1969 Patented Feb. 2, 1971 Assignee Ernest F. Donley Sons, Inc.

Cleveland, Ohio a corporation of Ohio SHAFT SEAL HAVING PASSAGE FOR HEAT- TRANSFER FLUID 19 Claims, 10 Drawing Figs.

U.S. Cl 277/22, 277/62, 277/72 Int. Cl F02f 11/00, Fl6j 15/40 Field of Search 277/22, 53, 59, 58, 71, 72, 72S.P., 74, 62

References Cited UNITED STATES PATENTS Primary Examiner-Samuel R. Rothberg Attorney-Bosworth, Sessions, l-lerrstrom & Cain ABSTRACT: A sealing system for a rotatable shaft, adapted to extend through a wall member or the like, wherein seal means disposed about the shaft and effective to form an essentially fluidtight enclosure-between the shaft and wall member also includes a heat-transfer system positioned inwardly of the seal relative to the shaft to regulate the environmental temperature and particularly that of the seal. The heat-transfer system comprises a continuous passage of two segments of travel which are preferably consecutive Each segment extends substantially axially of the shaft and performs a heat-transfer function. One of these segments lies along and outside of the shaft to contact it directly with the heat-transfer fluid.

SHAFT SEAL HAVING PASSAGE FOR HEAT-TRANSFER FLUID BACKGROUND OF THE INVENTION The present invention relates to a sealing system for a rotatable shaft and, more particularly, to such a system having an improved heat-transfer system for environmental temperature control of the shaft and its seal such as by cooling them.

The rapid growth of modern technology has produced an ever increasing range of new and exotic media to be pumped, mixed, or blended. This in turn has placed new and harsher performance demands on mechanical shaft seals utilized in various pumping and mixing equipment. In industry generally there is a need for sealing systems capable of withstanding adverse conditions, such as temperatures above ordinary room temperatures, conditions of high humidity, and environmental atmospheres characterized by the presence of steam, chemical vapors, and other troublesome factors. Often the incidence of one or more of these factors is complicated by the presence of subor superatmospheric pressures, either within or without a particular piece of equipment. When this is so, prevailing conditions often lead to quick deterioration, impairment of function and sometimes actual disintegration of sealing units characterized by sealing rings, packings, washers, and other components of felt, leather, and like materials.

The use of heat-transfer fluids to control the temperature of shafts and seals is not broadly new. Previously, for example, it has been suggested to use a deadend" quench, wherein means were provided to pass a coolant such as water to a nonreturn, predetermined point within the structure of the shaft seal. However, in time the coolant itself became heated and could eventually vaporize to form a vapor lock. Bearings also have been cooled by heat-transfer fluid, but this has no not been effective to cool an appreciable length of the shaft itself. Lubricants likewise have been used to cool shaft structures in addition to lubricating them, but this dual functionality has placed a limit to some extent on the cooling function, such as the rate of flow through the shaft and attendant parts.

SUMMARY OF THE INVENTION According to the present invention, a shaft and seal combination has a continuous passage for the flow of a heattransfer fluid wherein the passage, in the preferred form, reverses its direction to form two consecutive segments of travel which together can extend, for example, a distance approximately equal to twice the axial length of the seal. Each segment of the continuous passage in the present case performs a heat-transfer function, one of the segments lying along and contacting the outside (O.D.) of the shaft with the heattransfer fluid. In performing its heat-transfer function, the other of such segments may course through parts defining the seal; or pass through the shaft itself; or take the form of specially designed tubular conductors; and the like.

A further feature of the present invention resides in using the rotary movement of the shaft to pump a heat-transfer fluid through the continuous passage which preferably may be at substantially zero pressure. Still further, the pumping action can be of axialflow and/or centrifugal types.

BRIEF DESCRIPTION OF THE DRAWINGS ments of travel of the continuous passage;

FIG. is a partial section of FIG. 4 on the line 5-5;

FIG. 6 is a central axial section of a rotatable shaft and seal wherein a sleeve disposed about the shaft forms annular paths of travel defining the continuous passage;

FIG. 7 is a central axial section of a rotatable shaft and seal having a modified sleeve similar to the sleeve of the embodiment of FIG. 6 and illustrates the use of the present invention with another type of mechanical seal;

FIG. 8 is an offset section of FIG. 7 on the line 8-8;

FIG. 9 is a central axial section of a rotatable shaft and seal in which tubes laid within the periphery of the shaft form one segment of the continuous passage; and

FIG. 10 is an offset section of FIG. 9 on the line 10-10.

PREFERRED EMBODIMENTS OF THE INVENTION In the embodiment of FIGS. I through 3, a wall member I, which may be part o a pump housing or the like, has an opening 2 containing a rotatable shaft generally indicated at 3. On one side of the wall member 1, a stationary bearing assembly generally shown at 4 secures the shaft to the wall 1; and on the other side of the wall the shaft 3 supports a tool 5. This element, which does not form a part of the present invention, may be an impeller, mixer, stirrer, or any other element designed for rotary movement with rotation of the shaft 3. A mechanical seal, represented generally at 6, forms an essentially fluidtight enclosure between the shaft 3 and wall member 1. The shaft 3, bearing assembly 4, an and seal 6 together embody the heat-transfer system of the present invention.

More particularly, shaft 3 has a reduced, threaded end projection 7 onto which the element 5 screws or is otherwise fixed in a conventional manner. An open, central, axially disposed passage 8 extends through the shaft 3 from the end of the projection to approximately the center of the bearing assembly 4. That portion of the passage 8 within the projection 7 is filled by a tightly fitting plug 10 having an inner transverse slot to grip securely an end of a twisted strip defining an impeller vane 11. The vane extends for substantially the remaining length of the passage 8 which at the left-hand end (as viewed in FIG. 1) converts to a series of radially extending, outwardly curving exit channels 12. Shaft 3 has an integral flange portion 13 through which the channels extend, so that the extremities or ports of the channels lie on a radius of the flange portion which is greater than the radius of shaft 3. This induces a pumping action as hereinafter more fully described. At an end remote from the flange portion 13, shaft 3 has radially directed openings 14 to interconnect passageway 8 with its external surface. The size and number of such openings 14 may vary, depending on the quantity and rate of throughput desired for a heat-transfer fluid.

The bearing assembly 4 consists of two engaging

cylindrical parts

15 and 16 having aligned openings to pass the shaft 3. Part 15 has an outer flange l7 directed toward part 16, while the latter has an inner flange 18 directed toward part 15, the flanges 17 and 18 being of such sizes as to produce a mating engagement as shown in FIG. 1. Part 16 has a circumferential groove to receive a standard O-ring 20 to reduce leakage along the inner face of the two parts. Three bolts 21 spaced apart pass through aligned openings in

parts

15 and 16 to secure bearing assembly 4 to the wall member 1.

Parts

15 and 16 have cut-away annular areas 22 to receive bronze bearing rings 23.

Part 16 of the bearing assembly also includes means to introduce and receive a heat-transfer fluid with respect to the shaft and seal area. To this end, part 16 is formed with a volute 24 (FIG. 2) having its largest radius directed substantially vertically upwardly as viewed in FIGS. 1 and 2. The exit channels 12 of the passageway 8 empty into the volute 24. A drilled and internally threaded inlet opening 25 extends inwardly from a side of part 16 and then connects with the area between the mechanical seal 6 and rotatable shaft 3 throughzan angled conduit 26 (FIG. 3). A drilled internally threaded outlet 27 extends inwardly from the top of the bearing assembly (as viewed in FIGS. 1 and 2) to the volute 24. By means of the internally threaded ports,

openings

25 and 27 may be suitably connected to conventional, externally threaded pipe or tub- The nature of the mechanical seal 6 is not critical to the present invention. Many known seals, some of which are disclosed herein, may be used in connection with the present heat-transfer system. For example, the seal illustrated in FIG. 1 is described in U.S. Pat. No. 3,028,163 to Heinrich and in U.S. Pat. No. 3,131,941 to Donley, and therefore is not here described in extended detail. In general, the sealing unit 6 rides with a running fit on shaft 3. On one side, the seal makes sealing engagement with the wall member 1; and on the other it makes sealing engagement with the work tool 5.

More particularly, the seal unit 6 consists of two central, spring members 30 and 31 having inner inner, axially directed flanges which overlap and are resistant welded to each other. Each spring member 30 and 31 has an outer, oppositely directed flange 32 which overlap and are welded to, respectively,

annular support members

33 and 34. The latter have inwardly turned ends defining annular projections which ride upon frustroconical sealing rings 35 that may be composed of carbon, polytetrafluoroethylene, ceramics, or the like. The rings 35 have oppositely directed flanges which abut against other sealing rings 36 and 37 which may also be composed of carbon, polytetrafluoroethylene, ceramics, or the like. The rest of the mechanical seal between the wall member 1 and the rotatable shaft 3 consists of

annular members

38 and 40 of rigid sheet metal and for this purpose can be composed of alloys such as Monel and lnconel steel. Member 38 has an inner inturned lip which tightly grips a tapered face of ring 36 and may seat against the indicated shoulder thereon; and an outer flange which with a gasket 41 seals the area between the bearing assembly 4 and wall member 1. Member 40 comprises two overlapped and welded parts and has an inturned lip at one end which tightly grips a tapered face of ring 37; and an outer flange which with a gasket 42 seals the annular area between the shaft 3 and worktool 5. As is understood in the art, ring 37 serves as a drive element, rotating with the shaft and at a shaft speeds. Ring 36 is stationary with respect to the bearing assembly 4 or wall member 1. Intervening rings 35,

annular members

33 and 34, and spring members 30 and 31, all serve as a floating element which compensates for normal amounts of shaft deflection, misalignment, thermal expansion, and the like. In operation, the floating element automatically centralizes itself and rotates from zero to shaft speed, depending upon the friction difierential generated between the faces of the frustroconical sealing rings 35 and their companion sealing rings 36 and 37.

The heat-transfer system thus defined by the embodiment of FIGS. 1 through 3 comprises a passage having as one segment the passageway 8 and another segment the annular area around the outside diameter of the shaft 3 and the sealing unit 6. In FIG. 1, as well as in FIGS. 4, 6, 7 and 9, the clearance between the shaft and mechanical seal has been exaggerated for purposes of illustration. The order of travel for a heattransfer fluid through the segments of the passage is not critical, and the flow can initially go in either direction, if a pressure source is used, such as a pump, outside of the sealing system. Ordinarily, however, the direction of flow preferably is away from the force of gravity (which of course depends on the physical orientation of the entire unit), so that the heattransfer fluid, and especially a liquid, tends to fill the entire volume of the passage and flush out ahead of its flow any air or other gases from all dead space which otherwise might be bypassed. Further, if a self-pumping action, hereinafter described, is used; the fluid should leave the shaft in a direction consistent with the self-induced pumping action. In the case of the embodiment of FIGS. 1 through 3, the direction of normal flow is indicated by arrows; that is, in the inlet opening 25, through conduit 26, between the shaft 3 and sealing unit 6, radially inward through the openings 14, then through the passageway 8, radially out the channels 12 to the volute 24, and finally out the opening 27.

A significant feature of the present invention is the positive flow imparted to the heat-transfer fluid by a self-contained, pumping action resulting from the structure, and direction of fluid flow just described. In this manner, the heat-transfer system is not dependent on outside pressure. Indeed, the outlet 27 can be connected by conventional conduit directly to the inlet 25 without incorporating a pump. Means for adding makeup fluid to the system and heat-exchange means for the heat-transfer fluid may be included, if desired in the outer connections between

openings

25 and 27.

The centrifugal force attendant the rotation of shaft 3 provides a self-pumping action and produces a flow of the heattransfer fluid of substantially zero pressure. To obtain the centrifugal pumping action, the exit holes with respect to the shaft preferably lie on a greater radius with respect to the axis of rotation of the shaftthan the inlet holes to the passage. Thus it will be noted that outer ports of channels 12 in FIG. 1 lie on a radius that is greater than the radius of the rest of the shaft and especially the radial length of the openings 14. The pumping action results since the outlet ports of channels 12 travel at a greater peripheral speed than the outer portions of openings 14. However, alternate arrangements can be used as long as a pumping action results. For example, the outlet holes can be smaller than the inlet holes, if the outlet holes are at a sufficiently greater radius to overcome the size differential and still provide the necessary pumping action.

Additionally, the embodiment of FIGS. 1 through 3 contains a furtherself-pumping feature in that the twistedvane l 1. impels an axial flow as well of the heat-transfer fluid. Accordingly, this embodiment illustrates a preferred use of a combined, self-contained, positive axial flow and centrifugal pumping action. The pumping action is also self-compensating, that is, at higher speeds of shaft rotation, which generate greater amounts of hear, for example, the pumping action is correspondingly greater, also because of the greater speed in rotation.

FIGS. 4 and 5 illustrate an embodiment of the present invention in which the shaft has a hollow annulus defining one segment of the heat-transfer passage. In this case also, a wall member 44 has an opening 45 for a rotatable shaft generally indicated at 46. A stationary bearing assembly generally indicated at 49 secures the shaft 46 with respect to thewall 44. A mechanical seal, represented generally at 6, forms an essentially fluid-type enclosure between the shaft 46 and wall member 44. This seal is similar to that shown in FIG. 1 and. therefore the same reference numerals have been used to indicate like parts.

In particular, shaft 46 has a reduced section 46a which extends through the seal 6 and wall opening 45. A central, longitudinal bore 47 in the shaft has a diverging entrance which likewise has a section 470 of reduced diameter in that portion which extends through section 46a of the shaft. A rotatable, cone-shaped drive element 48 matches in configuration the entrance of the shaft bore 47 which the element 48 plugs. A bolt 50, threaded only for a relatively short distance at its end,

passes through an opening in a work element 51, such as a stirrer, and into the bore of the shaft section 460 from its other end to screw into an internally threaded hole 52 at the end of the plug 48. In this manner, the bolt 50 secures the work element 51 to an end of the shaft and simultaneously defines a hollow annulus 53 (FIG. 5) in the bore section 47a. At the end of shaft 46a near element 51, there are four radial passageways 54 reaching the outside diameter of the shaft. Additionally, adjacent the other end of the shaft there are four slanted radial paths 55.

The bearing assembly 49 of FIG. 4 consists of an annulus 56 having an externally threaded projection 57 which mates with a suitably threaded opening in the wall member 44. Bolts 58,.

conventionally connect a housing 60 to the annulus 56 and an O-ring 61 seals against leakage between these parts. Within the area between the housing 60 and shaft 46, a collar 62 and ring 63 cooperate to supply and receive a heat-transfer fluid with respect to the shaft 46 and seal 6. Collar 62 seats against a shoulder 64 in a radial flange of housing 60 and has an internal, circumferential channel 65 communicating with the outlets of the radial paths 55. An axially directed bore 66 in ring 62 reaches the channel 65.

Ring 63 is externally threaded to engage internal threads of the housing 60, as at 67, and seats against a shoulder 68 in the housing which also has a standard O-ring 70 conventionally to seal those parts against leakage. Ring 63 also has an inwardly extending radial flange 71 which forces collar 62 against shoulder 64 and leaves an empty annular area 72 between the collar 62 and housing 60. A pair of internally threaded

openings

73 and 74 extend axially of the ring 63. Opening 73 extends through the ring to the annular area 72. Opening 74 has a downwardly extended bore 75 which connects bore 66 of the collar 62 with opening 74. A standard packing gland 76 fits against the remaining side of the ring flange 71.

The heat-transfer system defined by the embodiment of FIGS. 4 and 5 comprises a passage having as one segment the hollow annular area 53 and as another segment the annular area around the outside diameter of the shaft section 46a and between it and the sealing unit 6. The flow of a heat-transfer fluid, such as water, is normally in the direction indicated by arrows; that is, through opening 73 to the annular area 72, radially inwardly between ring 56 and the shaft, axially along the shaft section 46a between it and the sealing unit 6, then radially inwardly through the passageways 54, now reversing its direction backwardly through the hollow annular area 53, out the slanted radial paths 55 to the circumferential channel 65, then through connecting bores 66 and 75, and finally out the opening 74. Since the outer ends of the paths 55 are at a greater radius than the outer ends of the passageways 54, there results the same type of centrifugal pumping action as previously described.

FIGS. 6 through 8 illustrate further embodiments in which a sleeve member encloses the rotatable shaft in spaced relation, thereby providing essentially annular paths of travel on opposite sides of the sleeve to define two segments of a continuous passage. Referring initially to the embodiment of FIG. 6, a bearing assembly indicated at 80 secures a rotatable shaft 81 to a wall 82 having an opening to receive the shaft. The shaft has stepped sections 810 and 81b. 81a and 81b, the latter making a conventional attachment (not shown) to a working element 83. A mechanical seal represented generally at 6 forms an essentially fluidtight enclosure between the shaft 81 and wall 82. This seal is similar to that shown in FIGS. 1 and 4 and therefore the same numerals have been used to indicate like parts. A sleeve, generally indicated at 84, rotates with shaft 81 and has a radial flange portion 85, equipped with a standard O-ring 86, which seats in a shoulder 87 formed by the step section 81a. A cup-shaped axial flange 88 extends from the flange portion 85 along the exterior of the shaft 81. The main body 90 of the sleeve is spaced outwardly from the stepped section 81a of the shaft and has an intumed rim 91 which seats against a shoulder 92 formed by the step section 81b and which, with the aid of an O-ring 93, makes a seal with the working tool 83. The sleeve 90 has four, equally spaced openings 94 adjacent the rim 91, while the flange portion 85 has four substantially radial exit paths 95 which communicate with an annular area about the shaft section 810 formed by the sleeve 90 spaced therefrom.

The bearing assembly 80 of FIG. 6 includes a housing 96 suitably secured against the wall 82 as by bolts (not shown).

Rings

97 and 98 seal off the exposed side of the housing. Small ring 97 abuts against the flange portion 85 and has an axial flange which is threaded to engage female threads of the housing 96. Ring 98 has a concentric groove 100. The outer side of the groove is threaded to engage the threads of ring 96, while the inner side telescopes beneath the axial flange of ring 97 to bear against a standard packing gland 101 atop the axial flange 88. Housing 96 has two opposed threaded

openings

102 and 103. Opening 102 has an angled channel 104 communicating with the area between the seal 6 and the outer side of sleeve 90, while opening 103 reaches an annular area 105 formed by housing 96 about the outer ends of exit paths 95.

The heat-transfer system thus defined by the embodiment of FIG. 6 comprises a passage having as one segment the outer annular area about the sleeve 90. and as another segment the annular area between the shaft section 81a and inner side of the sleeve. The flow of a heat-transfer fluid is normally in the direction indicated by arrows; that is, in opening 102, through channel 104 to the annular area between the seal 6 and sleeve 90, through openings 94, then reversing its direction of flow through the annular area between the sleeve and shaft section 81a, through exit paths 95, and finally out the opening 103. Since the outer ends of the exit paths are at a greater radius than the openings 94, there results a centrifugal pumping action as previously described.

FIGS. 7 and 8 illustrate a modified form of sleeve and another type of mechanical type of seal that may be used. In this embodiment, the wall member 1, working element 5, and bearing assembly 4 are similar to that shown in FIG. 1, and therefore the same numerals have been used to indicate like parts. In the bearing assembly 4, cylindrical part 16 preferably has a somewhat greater shaft opening than the corresponding part in FIG. 1 to accommodate a sleeve, while cylindrical part 15 may, if desired, have an annular flange 105 to form a secondary seal with a packing ring 106.

A rotatable shaft 107 is of uniform diameter except for a reduced threaded extension 108 which conventionally, securely holds the working element 5. A sleeve, represented at 110, is of general T-shape, the leg 111 of the T being hollow and encompassing the shaft 107 in a spaced apart relation. The end of leg 111 has an intumed rim 112, which seats against a shoulder 113 on shaft 107 formed by the extension 108. Adjacent the rim 112, the shaft has four equiangularly spaced openings 114. The head 115 of the sleeve is discshaped and has several (FIG. 8) radially extending paths 116 which reach the volute 24.

The mechanical seal of FIG. 7, generally indicated at 117, is disclosed in US. Pat. No. 3,131,941 to Donley, and therefore is not here described in extended detail. In brief, the seal consists of two central, spring members 1 18 and 120 having outer, axially directed flanges which overlap and are resistant welded to each other. Each spring member 1 18 and 120 has a bowed portion 121 of relatively short radius of curvature and consists of primary and secondary springs of matching configuration superposed one over the other. Sealing rings 122, one on either side of the welded

members

118 and 120, have tapered faces matching the angled, slanted, outwardly turned inner ends of the

members

118 and 120, so that the tapered faces and ends make an areal contact. The remainder of the mechanical seal between wall member 1 and rotatable shaft 107 consists of sealing

rings

123 and 124 which abut rings 122 and

annular members

125 and 126 of rigid sheet metal. Member 125 has an inner turned lip which tightly grips a tapered face of ring 123 and may seat against the indicated shoulder thereon; and an outer flange which with a gasket 127 seals the area between the bearing assembly 4 and wall member 1. Member 126 comprises two overlapped and welded parts and has an intumed lip at one end which tightly grips a tapered face of ring 124; and an outer flange which with a gasket 128 seals the annular area between the shaft 107 and work tool 5. The materials from which parts of the seal may be fabricated as well as its operation are known in the art and are similar to the previously described materials and operation for the seal of FIG. 1.

The heat-transfer system thus defined by the embodiment of FIGS. 7 and 8, like the embodiment of FIG. 6, provides concentric annular segments above and below sleeve 110, which define parts of a continuous passage. The flow of a heattransfer fluid is preferably in the direction of the indicated arrows; that is, in opening 25, through channel 26 to the area between the seal 117 and the outside of the sleeve leg 111, through openings 114, and backwardly to the left as viewed in FIG. 7 inside the sleeve leg 111 and wetting the shaft 107, then through exit paths 116 to the volute 24, and finally out the opening 27. Since the outer ends of the exit paths 116 are at a greater radius than the openings 114, there results the same type of centrifugal pumping action as previously described.

FIGS. 9 and 10 illustrate a still further modified embodiment in which one of the segments of the heat-transfer passage comprises a plurality of tubes rotatable with the shaft. In this embodiment, the wall member 1, working element 5, bearing assembly 4, and mechanical seal 117 are similar to the corresponding parts shown in FIG. 7, and therefore the same numerals have been used to indicate like parts. As one further modification, the cutaway annular area 22 for the cylindrical part 16 in the bearing assembly may have an L-shaped bronze bearing 129 to receive a ring 134 which rotates with a shaft 130.

The shaft 130 in FIGS. 9 and 10 has a series of axially extending grooves 131 which stop short of the end of the shaft. Each groove holds in fixed relation a tube 132, one end of which is spaced from the end of its groove to provide an open annular area 133. The other end of each tube 132 curves radially away from the shaft 130 and is encased in an aluminum ring 134 fixed with respect to the shaft and having a flange 135 which rides against the bronze bearing 129.

In the embodiment of FIGS. 9 and 10, the flow of a heattransfer fluid is normally in the direction of the indicated arrows, that is, in opening 25, through channel 26 to the open area between the mechanical seal 117 and the outside diameter of shaft 130, through area 133 into the ends of the tubes 132 for a reversal in direction of flow back to the left as viewed in FIG. 9, out the curved ends of the tubes to the volute 24, and finally out the opening 27.

Normally, the heat-transfer system serves as a heat sink, and the heat-transfer fluid is a coolant such as water at room temperatures or lower, ethylene glycol, nitrogen gas etc. However, it is within the contemplation of the invention to use a heat-transfer fluid which imparts heat to the system. For instance, it will be noted in FIGS. 1, 4, 6, 7 and 9 that the fluid worked upon by the respective elements 5, S1 or 83 has access to the outside of the seals 6 and 118. Certain fluids such as aqueous sugar solutions must be heated to maintain a desired viscosity or to prevent congealing. In this case, the heattransfer fluid can be hot water, steam, heated oil such as transformer oil, and the like.

Although normally the shaft rotates and the wall or equivalent member through which the shaft extends is relatively stationary, the reverse situation is possible and contemplated by the present invention and appended claims. For example, in tumbling driers the shaft is stationary and the outer element, such as as cage, rotates about the shaft. In such cases, exterior pressure means such as a pump may be needed to force a fluid through the heat-transfer system.

The present heat-transfer system provides an efficient technique for the environmental temperature control of a shaft and a mechanical seal. It is not necessary to provide a built-in pressure device to create a flow of a heat-transfer fluid; nor, indeed, to be dependent on a pressure source for this purpose which is outside of the apparatus containing the present heat-transfer system. Instead, the system has a selfcontained pumping action conducive to propelling the heattransfer fluid through a passage. Moreover this pumping action can be an axial flow and/or a centrifugal pumping action. Further, the present heat-transfer system and rotatable shaft combination requires no additive lubrication from either the media being pumped or other external sources.

It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.

We claim:

1. A sealing system comprising a shaft adapted to extend through a wall member or the like, a seal disposed about the shaft and effective to form an essentially fluidtight enclosure between said shaft and wall member, and a heat-transfer system to regulate the temperature of the seal, said heattransfer system being positioned inwardly of the seal relative to the shaft and comprising a'continuous, axially disposed,

reversing passage for the flow of a heat-transfer fluid having;.

two consecutive segments of travel, each segment extending substantially axially of. the shaft and adapted to performna heat-transfer function, at least one of said segments lying along and adapted to contact the shaft directly with said fluid, 1

the other of said segments being adapted to contact a side of the seal facing the shaft directly with the the heat-transfer fluid, and means to introduce and receive a heat-transfer fluid circulation of substantially the same heat-transfer fluid through said passage.

5. The sealing system of claim 1 wherein said passage has a port effective upon rotation of the shaft to provide a self-contained pumping action conducive to propelling the heattransfer fluid through said passage.

6 The sealing system of claim 5 wherein said port is an exit port.

7. The sealing system of claim 1 wherein one of said segments of travel is an axially extending passageway in the shaft, and including-means to connect said passageway with the exterior of the shaft 8. The sealing system of claim 7 wherein said shaft has radial openings to connect said exterior of the shaft with said passageway, and the passageway has exit ports substantially radially directed with respect to the shaft to expel the heattransfer fluid flowing therethrough.

9. The sealing system of claim 7 wherein said passageway is substantially coaxial with the shaft and contains a fixed axially extending vane effective upon rotation of the shaft to propel the heat-transfer fluid through the passageway.

10. The sealing system of claim 7 wherein said passageway is an annular area extending axially of the shaft.

11. The sealing system of claim 7 wherein said passageway. is substantially coaxial with the shaft and contains a fixed axially extending vane rotatable with the shaft, and said.

passageway has an exit port, whereby upon rotation of the shaft said vane and exit port provide a combined, self-contained, positive axial flow and centrifugal pumping action.

12. The sealing system of claim 1 wherein said heat-transfer system includes a sleeve substantially enclosing and spaced from the shaft and disposed between it an and said seal, thereby providing essentially annular paths of travel on opposite sides of said sleeve defining said two segments of the continuous passage.

13. The sealing system of claim 12 wherein said sleeve is fixed with respect to the shaft and has an opening to interconnect said two annular paths of travel defining the two segments of the continuous passage.

14. The sealing system of claim 12 wherein said sleeve is fixed with respect to the shaft and has a flange portion adjacent one end provided with outwardly directed port openings communicating with the interior of the sleeve and effective to serve as a centrifugal-flow impeller upon rotation of the shaft.

15. The sealing system of claim 1 wherein one of said segments of travel comprises a plurality of tubes rotatable with the shaft.

16. The sealing system of claim 15 wherein said shaft has axially extending grooves to receive said tubes, and a circumferentially extending groove in the shaft adjacent one alignment of common ends of the tubes to interconnect them to the exterior of the shaft.

17. The sealing system of claim 15 wherein said tubes extend radially outwardly of the shaft at one alignment of their common ends to serve as a centrifugal-flow 'impeller upon rotation of the shaft.

ments of the continuous, reversing passage are adapted to contact the shaft directly with said heat-transfer fluid.

Claims

1. A sealing system comprising a shaft adapted to extend through a wall member or the like, a seal disposed about the shaft and effective to form an essentially fluidtight enclosure between said shaft and wall member, and a heat-transfer system to regulate the temperature of the seal, said heat-transfer system being positioned inwardly of the seal relative to the shaft and comprising a continuous, axially disposed, reversing passage for the flow of a heat-transfer fluid having two consecutive segments of travel, each segment extending substantially axially of the shaft and adapted to perform a heat-transfer function, at least one of said segments lying along and adapted to contact the shaft directly with said fluid, the other of said segments being adapted to contact a side of the seal facing the shaft directly with the the heat-transfer fluid, and means to introduce and receive a heat-transfer fluid with respect to said continuous passage.

2. The sealing system of claim 1 wherein said heat-transfer fluid is a coolant.

3. The sealing system of claim 1 wheRein said segments of the continuous passage together extend a distance approximately equal to twice the length of the seal about the shaft.

4. The sealing system of claim 1 wherein said means to introduce and receive a heat-transfer fluid with respect to the continuous passage is interconnected to provide a repetitive circulation of substantially the same heat-transfer fluid through said passage.

5. The sealing system of claim 1 wherein said passage has a port effective upon rotation of the shaft to provide a self-contained pumping action conducive to propelling the heat-transfer fluid through said passage. 6 The sealing system of claim 5 wherein said port is an exit port.

7. The sealing system of claim 1 wherein one of said segments of travel is an axially extending passageway in the shaft, and including means to connect said passageway with the exterior of the shaft.

8. The sealing system of claim 7 wherein said shaft has radial openings to connect said exterior of the shaft with said passageway, and the passageway has exit ports substantially radially directed with respect to the shaft to expel the heat-transfer fluid flowing therethrough.

11. The sealing system of claim 7 wherein said passageway is substantially coaxial with the shaft and contains a fixed axially extending vane rotatable with the shaft, and said passageway has an exit port, whereby upon rotation of the shaft said vane and exit port provide a combined, self-contained, positive axial flow and centrifugal pumping action.

17. The sealing system of claim 15 wherein said tubes extend radially outwardly of the shaft at one alignment of their common ends to serve as a centrifugal-flow impeller upon rotation of the shaft.

18. The sealing system of claim 1 wherein said shaft is rotatable with respect to wall member.

19. The sealing system of claim 1 wherein both of said segments of the continuous, reversing passage are adapted to contact the shaft directly with said heat-transfer fluid.