US1673260A

US1673260A - Pump

Info

Publication number: US1673260A
Application number: US93820A
Authority: US
Inventors: Charles R Meston; Aleck W Meston
Original assignee: STACOLD CORP
Current assignee: STACOLD Corp
Priority date: 1926-03-11
Filing date: 1926-03-11
Publication date: 1928-06-12
Anticipated expiration: 1945-06-12

Description

June 12. 1928.

1,673,260 c. R. MEs-roN r-:T AL

PUMP

Filed Marca 11, 192e 3 sheets-sheet 1 im w , BY l mmm/( f ATTO NEYS June 12, 192s. 1,673,260

- Cv. R. MESTON El AL PUMP Filed March l1, 1926 3 Sheets-.Sheet 3 INVENTORS fqf'lr Mem!" /Zlcc/f Meat Patented June l2, 1928.

UNITED STATESl PATENT OFFICE.

CHARLES B.. MESTON AND' ALECK W. MESTON, OF YONKERS, NEW YORK, ASSIGNORS TO TBIE STACOLD CORPORATION, OF NEW YORK, N. Y., A. CORPORATION 0F NEW YORK.

PUMP.

Application led latch 11, 1926. Serial No. 93,820.

This invention relates to pumps and particularly to air or gas pumps such as are used in refrigeratingapparatus.

The invention has been particularly worked out in connection with pumps utilizing intermeshing gears for pumping air or gas. With this type'of pump, it 1s essential that the gear teeth fully intermesh and that there be no leakage of air around the teeth in the casingnat the outlet side of the pump or leakage from the casing around the pump shaft. When the pump is used. as a high pressure pump, it is very diiiicult to prevent leakage of air or gas from the discharge side of the pump. Furthermore, the high pressure acting on the pump elements tends to exert a thrust thereon and cause wear of the gears and contacting parts of tbe pump.

The invention has for its salient object to provide a pump so made as to obtain extreme accuracy in construction at a minimum manufacturing cost.

Another object of the invention is to provide a pump of the character described so constructed that there will be practically no leakage at the outlet or high pressure side of the pump.

Another object of the invention is to provide a structure ofthe character described in which the pressure is equalized at the ends -of the gear elements so that `no appreciable thrust is exerted on the gears.

Another object of the invention is to provlde a pump of the character described in f which the drive shaft is so connected to the pump that no leakage from the casing will occur around the shaft.

. Further objects of the invention will appear from the following specification taken in connection with the drawings, lwhich form a part of this application, and in which Fig. 1 is a sectional elevation of a pump constructed in accordance with theinvention;

Figs. 2 and 3 are transverse sectional elevations taken substantially on lines 2 2 and 3 3 of Fig. 11;.

Fig. 4 ,is a. sectional elevation taken substantially on line 4-4 of Fig. 1;

Fig. 5 is a sectional elevation taken mounting the gears and shaft bearings in straight bores, the bearings, bushings and gears will be positioned in accurate alinement thus providing extreme accuracy at a kminimum of expense in manufacturing.

If desired, to provide for taking upavear or other contingencies and to further insure an accurate fit, the plugs or bearing boxes have their centers disposed very slightly eccentric to the center of the bores inthe casing in such a manner that the pump gearing will accurately fit the casing at the discharge side of the pump but will clear thecasing at the inlet side of the pump. This prevent-s leakage at the high pressure side of the pump and prevent-s the gears -from dragging or rubbing on the casingat the intake side of the pump in case the gear shafts become worn or the bearings permit the gears to get out of alinement.

Means is also provided in the pump Afor eliminating end thrust and also for preventing lleakageof the air or gas from the pump casing around the drive shaft and for preventing air vfrom leaking into the casing. This is accomplished in one form of the invention by providing a drive shaft with a longitudinal recess at one end for receiving the gear. shaft. The recessed end of the drive shaft is iianged and the flange engages a' spring ressed collar, the s ring being enclosed wit in an expansible ran contractible metallic casing. The s ring presses ythe flange into engagement wit the collar and also presses the collar against a wall of the casing. The drive shaft is splined or keyed to the gear shaft. In another embodiment the drive shaft is splined or 4otherwise connected to drive one of the gears and is extended out through the casing end. 'A flange on the shaft engages a collar asin the Erst form described and prevents leakage. VBy means of this construction the gear shaft floats in its bearing and end thrust is 'largely eliminated.

Invthe form of the invention illustrated, sealing liquid is conducted to the ends of the gears thus equalizing the pressure at the ends of each lgear and a lubricant separate and distinct from the sealing liquid is used for lubricating the bearings.

Further details of the invention will appear from the following description.

The pump casing consists of a body` portion 10 and end plates 11 and 12. The body portion ispreferably cast in a solid block and is bored longitudinally to-form

straight bores

15 and 16. (See Fig.'3.) The-bores 15` and 16 as illustrated, consist of overlapping cylindrical opzenings which intersect in a common plane 1 There is positioned at each endpf each A bore a bearing box or plug 20 and 1n these bearing boxes or bearing plugs are mounted ball bearings 21. The bearing boxes or plugs 20. have substantially cylindrical outer surfaces but are formed with flat sides 22 adapted to be positioned in alinement with the common plane 17. v A

The pumping'elements consist of a pair of

intermeshing gears

25 and 26, herringbone gears being illustrated. The gear 25 1s mounted on aI shaft 27 and the gear 26 is mounted on a shaft 28, the shafts 27 andV 28 being mounted in the bearings 21v carried by the plugs 20..,VV

The straight bores thus receive the gears, shaftsand shaft bearings and because of this construction the elements specified can be accurately alined.

As shown in Figs. 5 and 6, the

bores

15 and 16 intersect in a knife edge 30 at the high. pressure or discharge sdeof the pump and 1t is very essentialthat the Vgear

teeth

31 and 32 of the gears 25 and `26 accurately lit the casing at this knife edge so asto prevent escape of the high pressure air or gas.

This' is accomplished by locating the plugs,V or bearing boxes 20, the gears, andgearV shafts in the

straight bores

15 and 16.

It has been found advantageous to 'compensate for wear and to further insure an accurate t of thel pump elements in the bores by locating th'ecenters of the plugs vor bearin boxes 20 slightly eccentricto the centers o the

bores

15 and 16. Such a structure is shown in Figs. 5 and 6, wherein the centers of the plugs are .located at a: and the centers of the bores are located at y. The point a: is located on 'a line disposed' substantially 45 from the .line y-'y connecting the centers of the bores. By so positioning the centers `of the bearing boxes or plugs, it will be clear that the gear teeth 31 and `32`will'bepositioned in full intermeshing relation with reference to each vother and these teeth will also accurately through aconduit 40 and opening 41 formed in the casing. The opening 41 communicates at its inner end with a recess 42 formed in the casing body opposite the knife edge l30.

The air or gas or -other substance being pumped leaves the casing body through

openings

45 and 46 formed in the plugs 20 and communicating with discharge conduits'.

47 and 48. l

In the form of the invention shown in Fig. 1, the drive shaft of the pump is s hown at 50 and is provided with a longitudinal recess 51. The shaft 5() has a fiange 52 formed on the end of the recessed portion thereof, the iiange being adapted to seat against a portion A 53 of the casing end plate 12.

The end plate 12 has formed thereon a boss 54 into which the shaft 50 extends and the' open end of the boss is closed by :a cap 55. A 4spring 56 seats at one endagainst the cap 55 and at its opposite end against a collar 57 which carries a packing 58 vadapted to engage the flange 52. A iex'ible'bellows is secured atone end to the collar 57 and.

at -its other end to a washer 59 which is securedl by the cap 55 against the outer end of the boss 54.

From the showing in Fig. 1 it will be seenV end Yplate 12, thus tending .to preventl the'4 escape vof any of the sealing liquid from the Y7 asimilar .shaft seal vis illus- AYtr'ated but infthis embodiment a an'ge 52^ is formed on the shaft 27f and this shaft is extended through the end plate and cap 55. The gear 25 is splined to or mounted on squared portion 27B of the shaft and is slidable thereon but rotatable therewith. .The flange 52A bears against collar or^washer 57 as before and the spring 56, washer 59, andbellows between washer 69 and collar 57A operate as in Fig. 1.

The body 10of the pump casing is mounted on a base plate 60 which in turn is mounted on and forms. the top for a cooling reservoir or chamber 61. Thecasingbody 10 has formed in its outer surface a pair trated, the liquid used for sealing the pump elements enters the cooling reservoir or chamber 61 through a conduit 70 and passes around a coil 71 disposed in the chamber 61 and through a conduit 72 to a strainer 73.

From the strainer 7 3 the sealing liquid passes through an opening 74 in the strainer casing into a conduit 75 which leads to annular recesses or grooves 76 formed on the l inner surface of the plugs 20 disposed at the ends of the gear 26. (See Fig. l.) Also, on referring to Fig. 2, it will he seen that the sealing liquid passes through a conduit 77 to a conduit 78 which is connected bv conduits 79 and 80 to the grooves 76 formed 1n the plugs 20 disposed at the ends of the gear 25. v

The conduit 77 also communicates with a conduit 81 which in turn conducts sealing llquld through minute passages 82 to the gear teeth, thus sealing the contactbetween the teeth and the casing at the high pressure side of thel pump.

Conduit 79 also conducts sealing liquid tp a. conduit 83 which in turn conducts the liquid to the outwardlv extending portion of the shaft 27 and the liquid thus conducted w1ll seal the contact between the collar 52 and portion 53 of the end plate 12.

The recess or chamber in the boss 54, around the bellows. is filled with oil at all times, due to the oil or sealing liquid that is forced out between flange 52 and wall 53 and to insure a supply of lubricant or oil in the chamber when the pump is started an opening 84 is provided in the boss. A plug 85 tightly closes this opening when sealing liquid is not being supplied to the chamber.

When the pump shuts down, unless all the valves are tight, there may be a vacuum in thepump and this tends to draw air into the pump. The admission of air is very deleterious to the pump especially where sulphur dioxide is the refrigerant and so it is very important to prevent air'frqm entering. This important functi'difis performed by the bellows and by sealing liquid in the chamber in boss 54, which seals the contact between washer 57 and ange 5255erA 52A.

In the form of the inventionl illustrated in the drawings, the sealing liquid is notl usedjn to lubricate the bearings but a. separate and distinct lubricant is used. l It will be noted that the en'd plates 11 and 12 are provided' It will be understood that the sealing liquid passes from the pump with the air or gas pumped, is extracted from the gas in a separator and returns to the coil 7l through pipe and under pressure of the gas or air delivered by the pump.

From the foregoing specification is will be seen that a pump'structure has been provided in which the gear elements will accurately fit the casing and prevent escape of air or gas and loss of pressure at the discharge side of the pump and in which the pumping elements will be free from or clear of the casing at the intake side thereof. Furthermore, by reason of the fact that the sealing Huid 'passes to both ends of the pump shafts, and by reason' of the form ofshaft seal and elimination of stuffing boxes, the pressure is equalized and end thrust is minimized.. The pump drive shaft has been so connected to the gearing that leakage from the casing around the shaft is eliminated or practically eliminated andthe pressure within the casing tends to prevent escape of air or gas from the casing.

Although certain specific embodiments of the invention have been particularly shown and described, it will be understood that the invention is capable of modification and that changes in the construction and 'in the arrangement of the variouscooperating parts may be made Without departing from the spirit or scope ofthe invention as expressed in the following claims.

What we claim is:

1. In combination, a casing, a shaft. mounted in' said casing` and extending through the wall thereof, a drive shaft 'telescoping with said shaft extens1on keyed thereto and slidable relativethereto, a flange formed on the outer telescoping member, a collar surrounding said member and engaging said flange, resilient means pressing said collar against said flange and an expansible and a eontraetible sheath surrounding said resilient means and secured to the collar and casing for preventing sealing liquid from leaking thereon.

2. In combination, a easing, a shaft mounted therein and extending outwardly through one wall thereof, a shaft having a recessed end slidably receiving the extended end of said first shaftand having a flange on the end thereof, a ,boss on said casing s urrounding said shafts and fiange and havlng an opening forming a pocket, a capon the outer end of said boss, the' shaft -ange be-A ing disposed in engagement with the wall of the casing, a Washer surrounding said shafts and engagmg said flange and a spring mounted between said cap-and said washer for pressing the Washer against the flange and the ange against the casing wall and a iexible metallic sheath secured between said cap and said Washer and surrounding said 'spring for preventing sealing uid from escaping.

In witness whereof, I have hereunto set In Witness whereof, I have hereunto set my hand this 8th day of March, 1926. ALECK W. MES'ION.