US1802813A - Seal construction - Google Patents

Description

April 28, 1931- H. A. GREENWALD 1,802,813

SEAL CONSTRUCTION Filed Jan. so, 1928 Gummy Patented Apr. 28, 1931- UNITED STATES PATENT OFFICE" HAROLD A. GREENWALD, F DETROIT, MICHIGAN, ASSIGNOR TO THOMAS C. WHITE- HEAD, OF DETROIT, MICHIGAN SEAL oonsrmrc'rrou Application filed January so, 1928. serial No. 250,624.

This invention relates to pump construc- -tions and has particular reference to the means employed for sealing the main shaft of the pump whereby the escape of fluid or the entrance of air along the main shaft is prevented.

The invention, while capable of many diversified uses, finds particular utility ,in connection with refrigerating apparatus wherein it is essential to the eflicient operation of the apparatus to provide some means for sealing the main shaft of rotary type pump.

While many forms of seals have heretofore been used for accomplishing the foregoing purpose, it has been found, that owing to the particular disposition of these seals in the system that they were required to resist considerable pressure and accordingly had a tendency to leak.

It is therefore one of the primary objects of the present invention to provide a construction wherein the sealing means is dis posed within a chamber arranged in communication with the return line of-the system so that the seal will be required to resist only the pressure of the refrigerant in the low pressure side of the system and as a consequence be less likely to leak.

Other objects and novel details of construction will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawing wherein,

Figure l is a fragmentary vertical sectional view through a pump showing the particular arrangement of the seals; and

Figure 2 is a view similar to Figure 1 showing a modified form of construction.

In general the device comprises a pump 10 of any suitable design but preferably of the rotary type, the one illustrated having the intermeshing gears 11 and 12 keyed upon the stub shaft and main shaft 13 and 14 respectively. The main shaft 13 preferably projects through one wall 15 of the pump casing and is adapted to be connected to a suitable prime mover (not shown). Extending outwardly from the wall 15 of the casing is a tubular projection 16 surround- 5 ing a portion of the shaft 13 and normally 'ence character 21. may be of any desirable design, but prefclosed by a cap 16' sleeved upon the shaft and bolted or otherwise detachably secured to the outer end of the projection 16 forming therewith an annular chamber 17. i As shown, the chamber 17 is provided at the lower end thereof with an opening 18 for receiving one end of the conduit 19 connected to the usual expansion coils (not shown). Thus it will be noted that the conduit 19 functions as a return passage for the refrigerant from the expansion coils to the pump and further that the chamber 17 constitutes an intake chamber for the refrigerant prior to its escape, through the passage 20 formed in the wall 15, into the pump so that the chamber 17 is on the low side of the system and accordingly is subject only to the low pressure of this side.

Arranged within the chamber 17 and surrounding the shaft 13 is a double seal construction indicated generally by the refer- This seal construction erably comprises a pair of seals, for instance, an inner seal 22 and an outer seal 23. The inner and outer seals are preferably of substantially the same design and comprise the nuts 24, headers 25, bellows 26 and coil springs 27. As shown, the nuts 24:

threadedly engage the shaft adjacent to and I upon opposite sides of the enlarged portion 28 of the shaft and maintain askets 27 against the inner and outer shoul ers 30 and 31 respectively formed by the enlarged portion 28. The headers 25 of both the outer and inner seals frictionally engage the inner wall of the cap 16' and the outer wall of a plate 32 respectively. As shown the plate 32 is detachably secured within a recessformed in the end wall 15 of the pump casing substantially flush with the outer surface thereof. The springs 27 preferably surround the shaft 13 between the headers 25 and nuts 24 so as to yieldably maintain or urge the headers into engagement with the cap 16 and plate 32 as heretofore pointed out. The bellows 26 also surround the shaft 13 and together with the coil springs 27 are noted that the parts 24, 25, 26 and 27 respectively of the double seals rotate as a unit with the shaft so that any fluid esca ing from the inside of the pump casing a on the shaft and into the chamber between the header 25 and outer wall of the plate 32 will be thrown by centrifu al' force away from the seals so that the 011 will not flow between the outer header 25 and cap 16.

Moreover with the foregoing arrangement, it will also be noted that inasmuch as the inner seal will function to normally prevent any fluid escaping from the pump casing into the chamber 17, the outer seal will be required to resist only the escape of the refrigerant contained in the chamber 17 which is at, its lowest -pressure owing to the fact that the chamber 17 is in the low ressure or expansion side of the system. owever, in the event that fluid leaks past the inner seal, the outer seal will also operate to revent the fluid from escaping along, .the s aft 13 to the exterior of the chamber 17.

Referrin now to the modified form of the invention illustrated in Figure 2, it

will be noted that the particular arrangement of the intake chamber in the s stem is substantially the same as in the rst described form, the only material difference between the two forms of the, invention is that the two seals 33 and 34 in the modified form are not capable of rotation with the shaft 13, but are rigidly secured to the wall 15 of the pump casing and the cap J 16, of the chamber 17 As shown the end portions 35 of' the inner and outer seals overlap and are secured to flanges 15' and 16" of the plates 15" and 16 respectively, while the headers 36 of the seals slidably engage the shaft 13 and have a bearing engagement with the oppositely disposed annular shoulders formed by the enlargedportion 24 of the shaft. For normally urging the headers 36 into bearing engagement with the said shoulders the coil springs 37 are provided, which as shown are housed within the expansible elements 38 and surround the shaft 13 upon opposite sides of the enlarged portion thereof.

Thus from the foregoing, it will be apparent that the herein described apparatus renders possible the production of a commercially satisfactory arrangement that is simple and compact in construction which makes its manufacture economically efficient.

What I claim as my invention is:

1. In combination, a pump having a wall provided with a fluid passage and a shaft opening, and provided about said opening with a laterally projecting tubular portion constituting a fluid chamber, said chamber being in open communication with said passage, a plate secured to the outer end of said chamber and having a shaft opening, a plate within said chamber and secured aforesaid and provided intermediate its ends with an enlargement, means for cong ducting a fluid to said chamber, and means for preventin such fluid from flowing longitudinally. o the shaft through the 0 enin the first mentioned plate, inclu ing 1n bellows surrounding the shaft between said enlargement and plates aforesaid.

2. In combination, a pump having a wall provided with a fluid passage and a shaft opening, and provided about said opening with a laterally projectin tubular portion constituting a fluid cham er, said chamber being in open communication with said passage, a plate secured to the outer end of said chamber and having a shaft opening,

a shaft in the openings aforesaid and provided intermediate its ends with an enlarge-' ment, means for conducting a fluid to said chamber, and means for preventing such fluid from flowing longitudinally of the shaft through the shaft opening in said plate, including a longitudinally expansible tube surrounding and extending longitudinally of said shaft between the enlargement and the plate aforesaid.

3. In combination, a pump havinga wall provided with a fluid passage and a. shaft opening, and provided about said assage and opening with a laterally projecting tubular portion constituting a fluid chamber, said chamber being in open communication with the passage aforesaid whereby fluid in the chamber is always free to pass through the passage into the pump, a plate secured to the outer end of said chamber and havinga shaft openin a shaft in the openings aforesaid, means or conducting a fluid to said chamber at a point between the pump Wall and plate aforesaid, and tubular means extending longitudinally of said shaft between said pump wall and plate, preventing the escape of fluid along the shaft through the plate but permitting the fluid to enter the passage in the pump wall.

4. The combination with a pumpcasing wall provided with a fluid passage and a shaft opening, and provided about said passage opening with a laterally projecting tubular portion constituting a fluid chamber in open communication with the passage aforesaid,- said chamber being provided at one side thereof with a fluid inlet, a plate secured to the outer end of said tubular portion and having a shaft opening therein, a shaft in the openings aforesaid, means for conducting a fluid to said inlet, and means associated with said shaft and late for preventing the fluid from said inlet rom shaft opening, and provided about said passage opening with a laterally Erojecting tubular portion constituting a uid chamber in open communication with the assage aforesaid, said chamber being provlded at one side thereof with a fluid inlet, a plate secured to the outer end of said tubular portion and having a shaft 0 enin therein, a shaft in the openings a oresaid, means for conducting a fluid to said inlet, a plate within said chamber and secured to said pump casing wall, and means preventing the fluid supplied to said chamber from the inlet from passing along the shaft within said chamber including sealing elements associated with the shaft and first and second mentioned plates aforesaid.

- In testimony whereof I aifix my signature.

HAROLD A. GRE ENWALD.

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