US1965783A - Liquid pumping mechanism - Google Patents

Description

July 10, 1934.

w. F. TRAUDT LIQUID PUMPING MECHANISM 2 Sh eets-Sheet 1 .Filed Aug. 6. 1950 N Filed Aug. 6, .1930 2 Sheets-Sheet 2 j fzyrma fi/M 4% kw,

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Patented July I0, 1934 LIQUID PUMPING MECHANISM William F. Traudt, Buffalo, N. Y.

Application August 6, 1930, Serial No. 473,35?

Claims.

This inventionrelates to pumping mechanisms or systems for handling liquids such, for instance, as acids or other chemicals, the leakage or escape of which would result in danger or annoyance 5. or entail objectional loss.

One usual arrangement heretofore employed for handling such liquids comprises a centrifugal pump located on the floor or .ground outside of the liquid storage tank andconnected by a suitable suction pipe to the tank. In such an arrangement the stufiing box of the pump shaft is subjected to the static pressure within the liquid tank, and the leakage of the liquid through the standing box is practically inevitable. .Another known arrangement is to mount a horizontal centrifugal pump, together with a primer for the pump on top of the storagetank or above the liquid level therein, but this arrangement also is objectionable since the stuffing box is subject to the static pressure of the liquid Within the priming chamber and leakage can occur through the stufiing box.

Among the objects of my invention are the following: to provide a pumping mechanism in which leakage of the pumped liquid through the pump stuffing box is efiectually prevented; also to provide a pumping mechanism which includes a priming device for the pumpand in which the stufiing box of the pump is arranged so as to prevent leakage of the liquid; also to provide a centrifugal pumping mechanism embodyi g a novel relationship of the pump stuifing box to the pump priming chamber whereby leakage of the liquid is prevented; and also to provide a pumping mechanism for liquids which embodies the other features of advantage and improvement hereinafter described and set forth in the claims.

In the accompanying drawings:

Fig. 1 is an elevation, on a reduced scale, of a liquid storage tank having mounted thereon a pumping mechanism embodying my invention.

Fig. 2 is an elevation, partly in section, of the pumping mechanism.

Fig. 3 is a sectional elevation, on an enlarged scale, of the stuffing box for the pump.

Fig. 4 is an elevation, partly in section, of a modified construction embodying the invention.

Referring first to the construction shown in Figs. 1 to 3, 10 represents a liquid storage tank which may be a container or reservoir of any suitable sort for the liquid to be pumped. 11 indicates the pump and 12 a priming chamber for the pump. The pump may be of known construction, but it is arranged vertically or with its rotary drive shaft 13 extending upwardly from the pump, and it may be driven by any suitable means, such for example as an electric motor. 14. mounted above the pump and connected to the upper end of the pump shaft 13. In the construction shown the pump 11, which is a centrifugal pump, and the priming chamber 12, are mounted side by side on a suitable base 15 which is stationarily secured on top of the liquid storage tank. The suction intake pipe 16 of the pump connects with the lower end or portion of the priming chamber 12, and a suction line connects the priming chamber with the liquid storage tank, the suction line communicating at its lower end with the tank at the bottom of the latter, and communicating at its upper end with the priming chamber at an elevation above that at which the priming chamber communicates with the pump intake 16. This suction line, as shown, is formed by a bottom suction connection 17 on the priming chamber, a pipe 18 detachably coupled to said connection and extending therefrom down into the storage tank, and a pipe 19, which is arranged vertically within the priming chamber, is connected at its lower end by a screw or other suitable joint with the suction connection 17, and opens at its upper end into the upper portion of the priming chamber. The upper end of the priming chamber is closed preferably by a removable cover 20 which may be tightly secured in closed position, as by a clamp 21. The pump discharge pipe or line 22 extends from the pump to a higher level.

Before the pump is first started for drawing liquid from the storage tank, the priming chamber 12 is filled with the liquid, preferably up to the level of the top of the suction pipe 19, which can be done by removing the cover 20 or inany other suitable way. The intake 16 of the pump being connected to the bottom or lower portion of the priming chamber 12, the pump will be primed by the liquid from the priming chamber, and when the pump is started, it will draw the liquid from the priming chamber, lowering the level of the liquid therein. Since the lower end of the suction line is sealed by the liquid in the tank 10, a partial vacuum is thus created in the priming chamber above the liquid, and this, if the suction line is air bound, will draw the air from the suction line and cause the liquid to rise in the suction line and enter the priming chamber. The capacity of the pump intake and the priming chamber up to the level of the upper end of the suction pipe should be at least'equal to and preferably somewhat greater, than the capacity of the suction line from its lower to its upper end, so that the liquid will rise through the suction line and enter the priming chamber 12 before the priming chamber can be emptied sufficiently to uncover the pump intake and permit air to enter the pump. Thus, after the priming chamber has once been filled and the pump started, the pump can continue in operation and will be kept primed until the storage tank is emptied, or the liquid lowered in the same to the lower end of the suction pipe 18. If the pump is stopped before the liquid in the storage tank is lowered to the bottom end of the suction pipe 1'7, the liquid will backwash from the pump discharge pipe 22 through the pump and pump intake 16 into the priming chamber 12, and if the volume of liquid in the discharge pipe is more than enough to fill the priming chamber 12 up to the level of the upper end of the suction pipe 19, the liquid will enter the suction pipe 19 and flow back into the storage tank. Liquid is thus always kept in the ,priming chamber and the pump is kept primed, so that it can be again started to withdraw more liquid from the storage tank, and this action can be repeated until the tank is emptied.

According to my invention, the casing of the centrifugal pump is provided with an extension or sleeve which projects upwardly around the pump shaft 13 and is provided at its upper end with a stufiin'g box through which the pump shaft extends. This casing extension, in the construction shown, is formed by a tube 23 secured at its lower end by a liquid-tight joint to the pump casing proper, and a stuffing box or hollow casting 24 which is secured by a liquid-tight joint to the upper end of the tube 23. The stuffi-ng box may be of usual construction having an adjustable gland 25 and screw cap 26 at its upper end for compressing suitable shaft packi-ng 2'7 surrounding the pump shaft within the stuffing box. The upper or outer end of the stufbox, which constitutes a part of the upward extension of the pump casing, is located at a level above the upper end of the suction pipe 19 in the priming chamber, and therefore at a level above the highest level to which the liquid can rise in the priming chamber. Because of this location of the stufiing box relatively to the priming chamber, there can be no leakage of the liquid out through the stufling box and the loss of the liquid or danger or annoyance from leakage of the same is prevented.

The pump may advantageously be of the type, well known in the art, which produces a suction at both faces of the shroud, so that suction will be created around the impeller shaft where the shaft enters the pumping chamber. Pumps of this type are disclosed, by way of example, in the patents to Jackson, 440,252 of November 11, 1-890, and 'Schoene, 768,911 of August 30, 1904.

Preferably the upper end of the stufling box is submerged in a body of oil or ot er suitable liquid 30 contained in a receptacle 31 into which the upper end of the stuffing box projects. This receptacle :31 as shown is mounted on a bracket 32 secured to the upper portion of the priming chamber 12 and forms the support for the frame 33 on which the driving motor 14 for the pump and the upper bearing 34 for the pump shaft are mounted. By thus keeping the upper end of the 'stufiingbox submerged in oil, the pump can be operated for pumping liquid from a tank containing a vacuum or under a condition where, due toa high suction lift on the suction pipe a vacuum might be created -in the pump column 23. The oil will seal the shaft opening of the stuiiing box and prevent entrance of air through the same.

The pump mechanism shown and described, comprising the pump and the priming chamber mounted on the base 15, and the driving motor mounted on the prirmng chamber, constitutes a unitary structure which can be handled and readily installed as a unit on top of the storage tank and connected to the suction and discharge pipes.

In the mechanism, as thus far described and as illustrated in Figs. 1 to 3, the pump is primed automatically or kept primed, and the mechanism performs as stated without the necessity for any valves or closure devices for maintaining the priming body of liquid in the priming chamber or suction line. This simple construction adequately meets ordinary requirements. Certain additional advantages, however, are obtained by the construction shown in Fig. 4.

This latter construction, shown in Fig. 4, is the same as described and illustrated in Figs. 1 to 3, except that the suction line is provided with a check valve 35, preferably located at the lower end of the suction pipe 18, and an open air pipe 36, which is preferably of small size relatively to the suction line, communicates with the priming chamber 12 above the highest level which the liquid reaches therein, and extends down into the storage tank substantially to its bottom.

Without the check Valve 35 and air pipe 36, when the pump stops, the liquid in the discharge line would backwash into the priming chamber and force the air therein out through the suction line; thus after the backwash had been completed, the suction line would remain full of air, particularly if the volume of the discharge line did not equal the volume of the priming chamber.

But with the check valve 35 in the suction line, the backwash will force the air trapped in the priming chamber out through the small pipe 3.6, allowing the liquid to remain in the entire suction line. The small auxiliary air pipe will not interfere in any way with the proper operation of the pump. The added check valve and small air pipe therefore extend the usefulness of the apparatus as a whole and make it more flexible.

I claim as my invention:

1. In combination, a pump, a priming chamber communicating with the pump intake, said parts being constructed so that liquid .can backwash through the pump into said priming chamber, a suction pipe communicating with said priming chamber at a level above that to which the liquid rises in said priming chamber, means which prevent backflow of liquid from said suction pipe, and an air passage extending from the priming chamber at a point above the liquid therein to a point. submerged in the body of liquid being pumped.

2. In combination, a liquid holding tank, a pump for discharging the same, a-priming chamber communicating with the pump intake, said parts being constructed so that liquid can backwash through the pump into said primingchamber, asuction pipe extending from said tank and communicating with said priming :chamber at a level above that at which the pump intake communicates with the priming chamber, a check valve which prevents discharge of liquid from the suction pipe into the tank, and an air passage extending from the upper portion :of the priming chamber and communicating with the lower portion of said tank.

3. A pump unit comprising a base, a :priming tank mounted on said base" and extending upwardly therefrom, a centrifugal pump also mounted on said base adjacent the lower part of said tank, said pump having an impeller shaft extending upwardly therefrom to a height above the upper end of said tank; said pump also having a tubular shell extending around said shaft also to a height above said tank, means connecting the upper end of the shell to the upper end of said tank whereby the upper ends of said shell and tank steady one another, a stufiing box at the upper end of said shell through which said impeller shaft extends, means connected to the upper end of said shaft for driving it,'a bearing for the upper end of said shaft disposed above said stufling box and connected for support to the upper end of said shell, a pipe connecting the lower part of said tank to the suction inlet of said pump, and a riser suction pipe opening into said tank adjacent the upper end thereof, whereby liquid will be drawn through said suction pipe into and through said tank on its way to said pump, and liquid in said tank will prime said pump automatically at the starting of the pump.

4. A pumping mechanism for lifting a liquid from a lower level to a higher level and comprising a pump located between said levels, a priming tank at a level above said pump and below said higher level, a suction pipe extending from the inlet port of said pump into the liquid to be elevated and including, in series therein, said tank with the connection from the tank to the pump opening into the lower part of the tank and with the portion of the suction pipe that leads to said tank from said liquid, opening into the upper part of said tank, whereby liquid elevated by said pump will pass through said tank on its way to said pump, a delivery pipe leading from said pump to said higher level, whereby back wash in said delivery pipe upon stopping of said pump will cause some filling of said tank to provide a priming supply therein, an automatic check valve in said suction pipe between said tank and the inlet end of said suction pipe, and a relatively small air pipe opening at one end into the upper part of said tank-and at its other end depending into the liquid to be elevated, whereby when said pump stops, the suction pipe and said tank will be kept substantially filled.

5. A pumping mechanism for lifting a liquid from a lower level to a higher level and comprising a pump located between said levels, a prim-- ing tank at a level above said pump and below said higher level, a suction pipe extending from the inlet port of said pump into the liquid to be elevated and including, in series therein, said tank, with the connection from the tank to the pump opening into the lower part of the tank, and with the portion of the suction pipe which leads to said tank from said liquid opening into the upper part of said tank, whereby liquid elevated by said pump will pass through said tank on its way to said pump, a delivery pipe leading from said pump to said higher level whereby back wash from said delivery pipe upon stopping of the pump will cause some filling of said tank, said pump having a vertically extending operating shaft, a sleeve surrounding said shaft and extending from the pump casing to a level above the maximum possible liquid level in said tank, a stufiing box between 1:00 the upper end of said sleeve and said shaft, whereby the maximum elevation to which liquid will rise in said sleeve, when said pump is quiet, will not exceed the maximum possible upper liquid level in said tank and reach said stufiing box, an 105 automatic check valve in said suction pipe between said tank and the inlet end of said suction pipe, and a smaller air vent pipe opening at one end into said tank adjacent the upper end thereof having its highest point below said stuffing box, and opening at its other end into said liquid to be elevated, whereby upon a stopping of the pump the suction pipe will be kept substantially filled, a supply of priming liquid will be available in said tank, and the pressure on the liquid in the pump 115 tending to cause it to rise in said sleeve will not cause an elevation of liquid in the sleeve above the highest point of said small air vent pipe.

WILLIAM F. TRAUDT.

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