US1732871A - Rotary machine - Google Patents

Description

ROTARY MACHINE Oct' 22s Filed Nov. 5G' 1927 Patented Oct. 22, 1929 UNITED STATES IRVEN H. WILSEY, OF CHICAGO, ILLINOIS ROTARY MACHINE Application led November 30, 1927. Serial No. 236,661.

The present invention relates to improvements in rotary machines, and particularly rotary gear pumps of the type disclosed in my copending application, Serial No. 204,- 467, filed July 9, 1927.

The primary object of the present invention resides in the provision in a rotary machine adapted to handle fluids of a new and improved packing which will prevent objectionable leakage and which will not deteriorate appreciably through action of the fluid.

In ordinary rotary machines, such a rotary gear pumps adapted to handle fluids under relatively high pressures, leakage may ocur along the drive shaft. This of course is objectionable, and particularly so where the fluid is an acid or corrosive oil, such as fuel oil. Heretofore, various types of packings, including seal ring packings with lapped bearing surfaces, have been yprovided to correct this difficulty. Packing relying on lapped bearing surfaces for an effective fluid seal may operate satisfactorily for a while, but in a relatively short time, if corrosive uids under high pressures are being handled, some Huid will work between these surfaces and corrode them, thereby destroying the seal. An important object of the present invention therefore resides in the provision of novel means for venting the packing to the low pressure side of the machine, thereby maintaining a relatively low pressure at the packlne.

L further object resides in the provision in a rotary gear pump of a new and improved fluid seal which will vent automatically to the suction side of the pump regardless of the direction of rotation of the pump.

Another object is to provide a sea-l ring packing in which the pressures acting on the seal ring are maintained substantially in balanced relation.

A further object resides in the provision in a seal ring packing of the above character of meansfor preventing the passage of iiuid between the bearing surfaces through capillary action.

Furtlier objects 'and advantages will become apparent as the description proceeds.

In the accompanying drawings, Figure 1 is a side elevation of a pump embodying the features of my invention.

Fig'. 2 is a longitudinal vertical sectional view of the pump.

Fig. 3 is a sectional view taken along line f -3 of Fig. 2.

Fig. 4 is an end view of the venting collar.

Fig. 5 is a sectional View taken along line 5-5 of Fig. 4.

Fig. 6 is a fragmentary sectional View of a modified form of packing.

Fig. 7 is a longitudinal vertical sectional view similar to Fig. 2 but showing another modified form of packing.

Fig. 8 is a sectional view taken along line 8-8 of Fig. 7.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

The exemplary embodiment of the inven tion is shown incorporated in a single stage rotary gear and pinion pump, but it is to be understood that it may be used in a large variety of pumps and rotary machines. In the present instance, the pump comprises a suitable casing 10 which preferably is cylindrical in shape, and which is formed with a cylindrical chamber 11 open at one end. Of the casing 10, the open end is closed by a removable cover plate 12 secured thereto by any suitable means, such as a plurality of screw bolts 13, and the other end is formed with a central bearing 14 having a bore 15 opening to the inner end of the chamber 11. Suitable inlet and discharge passages 16 and 17 open respectively to opposite sides of the chamber 11, and preferably are formed in fittings 18 and 19 integral with the casing l0.

Rotatably mounted in the cylindrical chamber 11 is a rotor 20 which is provided with a drive shaft 21 adapted to be connected to a suitable source of power (not shown).

The rotor preferably comprises a circular plate which bears against the inner end of the chamber 11, and which has a close peripheral bearing Contact with the inner peripheral surface of the chamber. Formed on the front end of the rotor 20 are a plurality of laterally projecting and peripherally spaced internal gear teeth or vanes 22. These teeth are concentric with respect to the shaft 21, and mesh with a pinion 23 eccentrically related thereto. Preferably, the pinion 23 is mounted on a pin 24 journaled in a suitable bearing 25 in the cover plate 12. A crescent partition 26 is disposed between the rotor vanes 22 and the pinion 23. In operation, if the shaft 21 is rotated counter-clockwise, as viewed in Fig. 3, fluid will enter through the suction passage 16 to fill the interdental spaces between the teeth of the rotor 20 and the pinion 23 at the suction side of the partition 26, will then be carried past the partition 26 into the discharge side of the pump, and from there will be discharged through the passage 17. Obviously, if the rotation of the shaft 21 is reversed, the passage 17 will be the inlet passage and the passage 16 will be the discharge passage.

Considerable difliculty is ordinarily encountered in preventing leakage from the chamber 11 past the rotor bearing surfaces and along the shaft 21 through the bearing 14. This is particularly so when corrosive fluids such as acid fuel oil are handled which in a short time, pit and corrode the bearing surfaces, thereby resulting in leakage. The

present invention contemplates the provision of a new and improved packing for the shaft 21 which Will prevent leakage, and which will not deteriorate appreciably over a substantial period of time through any action of the fuel Oil or other iuid passing through the pump.

The packing comprises a bushing 27 Hired in the outer end of the bore 15, and providing a rigid bearing for the shaft 21. The inner end of the bore 15, between the rotor 20 and bushing 27 is slightly enlarged in diameter to form a chamber 28. Disposed on the shaft 21 is a seal ring 29 which is connected through a suitable flexible diaphragm 30, to the rotor 20. In the present instance. the ends of the diaphragm 30 are soldered respectively to the rotor shaft 21 and the seal ring 29 near its outer periphery. thereby defining afluid tight chamber 31 normally filled with a heavy lubricant. Preferably the diaphragm 30 is made of resilient material. The outer end of the seal ring 29 is provided with a lapped bearing surface 32 which is adapted to bear against another fixed lapped surface as hereinafter described. It will be evident that in the construction thus far described, the pressure in the chamber 31 will be atmospheric, and the pressure in the chamber 28 would be that of the discharge passage 17 if no vent were provided. This pressure difference would tend to force fluid between the lapped sealing surfaces which would soon destroy the effectiveness of the latter.

Means is provided for venting the chamber 28 to the suction side of the pump. To this end, two vent passages 33 and 34 are formed in the casing 10, and connect the passages 16 and 17 to opposite sides of the chamber 28. Preferably, the passages 33 and 34 open at diametrically opposed points in the inner end of the bushing 27, and are adapted to be closed selectively by a venting collar 35. The venting collar 35 is rotatably disposed on the shaft 21 between the inner end of the bushing 27 and the outer end of the seal ring- 29, and its opposite ends are lapped to provide sealing surfaces 36 and 37 bearing respectively against the lapped surface 32 of the seal ring and the inner lapped end surface 38 of the bushing 27. Formed in the periphery of the collar 35 is an arcuate notch 39 which receives a pin 40 projecting from the end of the bushing 27. The pin and notch connection between the bushing 27 and the venting collar 35 permits a limited rotational movement of the latter through frictional drag with the seal ring and the shaft 21 upon reversal of rotation of the latter. 35 is formed with two spaced ports 41 and 42 opening therethrough, and arranged for movement into selective registration with the passages 33 and 34 upon rotation of the collar into either of its extreme positions. It will be evident that by means of this construction the chamber 28 will be vented automatically to the suction side of the pump regardless of the direction of rotation of the shaft 21, thereby maintaining a relatively low pressure therein, and that as a result the fluid leaking from the chamber 11 will not enter between the lapped sealing surfaces.

To provide a balance for the seal ring 29, the outer end is provided with a deep annular notch 43 providing an annular space between the ring and the collar to which the ports 41 and 42 open. By this construction, the surface 32 is maintained close to the shaft 21, and the pressure on the exposed part of the ring is opposed to the pressure in the chamber 31.

In some instances, where the Huid in the chamber 31 is heavier than the Huid in the chamber 28, to prevent a tendency of capillary action to carry fluid past the lapped surfaces.l I have provided a seal ring 44 (see Fig. 6) having beveled edges 45 and 46 at opposite sides of the lapped surface. These beveled edges may be inclined at different angles for fluids having different viscosities.

In Figures 7 and 8 I have shown a modified form of the invention in which the automatic venting collar is omitted. In this form passages 47 and 48 directly connect the pas- 'Ihe collar 9 is ing to the high sages 16 and 17 respectively to the chamber 28. The outer end of each passage is screwthreaded, and is adapted to receive a sci-ew plug 49. 1n use, the passage 47 or 48 openpressure side of the pump is closed by the plug 49.

Referring to Figs. l to 6, instead of having the passages 33 and 34 opening in the end of the bushing 27, they may open in the peripheral wall of the chamber 28. In

this event, the venting collar 35 should have a peripheral contact with the inner peripheral wall of the chamber 28 so as to selectively close one or the other of the passages in the same manner as described in the foregoing.

I claim as my invention:

1. A rotary machine having, in combination, a casing having relatively high and low m) pressure spaces, a fluid handling mechanism in said casing, said mechanism comprisinga rotary element, an operating shaft for said rotary element, a seal ring mounted o n said shaft, said seal ring and a. portioniof said casing having coacting lapped surfaces, a flexible titl diaphragm connecting said seal ring'to said rotary element, and means for venting the space about said seal ring and said surfaces to said low pressure space.

2. A rotary machine having, in combination, a casing having relatively high and low pressure spaces, a fluid handling mechanism in said casing, said mechanism comprisinga rotary element, an operating shaft for said rotary element, a seal ring mounted on said shaft, a flexible diaphragm connecting said seal ring to said rotary element, a pair of passages extending from the space about said seal ring respectively to said spaces, and a collar having a limited rotary movement on said shaft and adapted to close said passages selectively upon angular movement into its extreme positions, said ring, said collarl and said casing having coacting lapped surfaces.

3. A rotary machine having, in combination, a casing having an inlet passage and a discharge passage, a gear rotor in said casing, a pinion eccentiically related to said rotor and meshing therewith, a partition located between said rotor and said pinion, a shaft for driving one of said gear elements, a bushing on said shaft, a seal ring on said shaft having a lapped surface on one end, a Hexible member effecting a. fluid tight connection between the other end of said seal ring and said shaft, a venting collar disposed between said ring and said bushing, said collar having a lapped surface .coacting with said hrst mentionedsurface and having a relatively limited rotary movement, a pair of venting passages leading respectively from said inlet and discharge passages to said venting collar, and a pair of ports in said collar adapted to be moved selectively into registration with the openings of said venting passages, and opening to the space about said ring.

4. A rotary machine having, in combination, a casing having relatively high and low pressure spaces, a fluid handling mechanism iii said casing, said mechanism comprising a rotary element, an operating shaft for said rotary element, a seal ring mounted on said shaft, a diaphragm connecting said seal ring to said rotary element, a member on said shaft, said ring and said member having coacting bearing surfaces, and means for venting the space about said ring automatically to the low pressure space re ardless of the direction of rotation of said s aft.

5. A rotary machine having, in combination, a casing having relatively high and low pressure spaces, a fluid handling mechanism in said casing, said mechanism comprising a rotary element, an operating shaft for said rot-ary element, a bushing for said shaft, a seal ring mounted on said shaft, fluid tight means connecting one end of said seal ring to said rotary element, a collar bearing between said bushing and said shaft, and means controlled by said collar for venting the space about said ring to said low pressure space.

6. A rotary machine having, in combination, a casing having relatively high and low pressure spaces, a Huid handling mechanism in said casing, said mechanism comprising a rotary element, an operating shaft for said rotary element, a seal ring mounted on said shaft, fluid tight means connecting said seal ring to said rotary element, and a member caring against said seal ring, the inner edge of the bearing surface of said ring being beveled.

7. A rotary machine having, in combination, a casing having an inlet passage and a discharge passage, a gear rotor in said casing, a pinion eccentiically related to said rotor and meshing therewith, a partition located between said rotor and said pinion, a shaft for driving one of said gear elements, a bushinor for said shaft, a seal ring on said shaft having a lapped surface on one end, a flexible member effecting a fluid tight connection between the other end of said seal ring and said shaft, a venting collar disposed between said ring and said bushing, said collar having a lapped surface coacting with said First inentioned surface and having a relatively limited rotary movement, means controlled by the position of said collarffor venting the space about said ring to said inlet passage, said ring having a peripheral notch in the end having the lapped surface.

8. A rotary machine having, in combination, a casing having relatively high and low pressure spaces, a fluid handling mechanism in said casing. said mechanism comprising a rotary element, and an operating shaft, for said rotary element, the pressure in said spaces being interchangeable by reyersal of said rotary element, coacting sealing members, one having a luid tight connectlon with said casing, and another having ailuid tight connection with said shaft, one of said connections being yieldable, and

means automatically operable to vent the space at one side of said yieldable connection to the low pressure space regardless of the direction of rotation of said rotary element.

9. A rotary machine having, in combinat-ion, a casing having relatively high and low pressure spaces, a fluid handling mechanismin said casing, said mechanism comprising a rotary element, and a shaft for said element, said casing being formed with two vent passages, one leading from each of said spaces and terminating in a port opening to the space about said shaft, a shift-able member having two openings adapted to be moved alternately into and out of communication with said ports respectively upon movement of said shitable member in opposite directions, and means for shifting said shiftable member upon reversal of rotation of said shaft.

10. A rotary machine having, in combination, a casing having two separate spaces, fluid handling mechanism in said casing, said mechanism comprising a rotary element, and a shaft for said element, said casing having two vent passages, one leading from each of said spaces and terminating in a port opening to the space about said shaft, a rotatable member positioned over said ports and having two openings adapted to be moved alternately into and out of communication with said ports respectively upon rotation of said member in opposite directions, and means for rotating said member upon reversal of rotation of said shaft.

11. A rotary machine having, in combination, a casing,relatively reversible high and low pressure spaces, Huid handling mechanism in said casing, said mechanism comprising a rotary element, two vent passages leading respectively from saidv spaces and terminating in ports opening to the space about said element, a rotatable member overlying said ports and having two openings adapted to be moved alternately into and out of communication with said ports respectively upon movement of said member in opposite directions, means for limiting the movement of said member and means for rotating said member upon reversal of rotation of said element.

In testimony whereof, I have hereunto axed my signature.

IRVEN H. WILSEY.

Images