US3015279A

US3015279A - By-pass for pumping apparatus

Info

Publication number: US3015279A
Application number: US763658A
Authority: US
Inventors: Leonard M Nechine
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1958-09-26
Filing date: 1958-09-26
Publication date: 1962-01-02
Anticipated expiration: 1979-01-02

Description

Jan. 2, 1962 L. M. NECHINE 3,015,279

BY-PASS FOR FUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 1 hl l l\ Jan. 2, 1962 M. NEcHlNE 3,015,279

BY-PASS FOR PUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 2 Jan. 2, 1962 l.. M. NECHINE 3,015,279

BY-PAss FOR PUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 5 Filed Sept. 26, 1958, Ser. No. 763,658 6 Claims. (Cl. 103-11) 'This invention relates to pumping apparatus and is particularly concerned with a novel ilow system through which sewage may be delivered to a sewage basin while pumps are operating to Withdraw sewage through said system Vfrom said basin.

It has been customary to provide a single ow system comprising a pump and apump by-pass valve so arranged that sewage delivered to the system through a main sewage inlet may ow through the system and around .the pump to the basin when the pump is idle. In such systems the pump often wasdesigned for greater lift than required by actual conditions, or discharge pressures changed as a result of -varying operating loads. The variations in the pressure ofthe pumpow create greater or less differential pressures on the upstream and downstream sides o f the by-fpass valve. These diierential pressures affect the by-pass valve in a manner to cause unstable operation of said by-pass, valve, with resultant leakage and loss of pressure in the pump ow.

In accordance with the present invention the ow of sewage or other liquid to and from the sewage basin is through a ow system that preferably includes two ,or more pumpsfand associated by-pass valvesI selectively operated in such manner that any or all of the pumps may operate to pump sewage from the basin without impeding the flow of sewage to the basin. For yconvenience, the system comprising the invention will be described as a two-pump installation, but it will be understood that it is not limited to two pumps, and maybe used with a single pump or with more than two pumps.

Separate pump control means are provided to sequentially start and stop the pumps. The operation of the control means is such that when the liquid in the basin reaches a predetermined high level, a first pump is operated to pump liquid from the basin. Operation of this pump closes a related by-pass valve and a Vcheck valve in the inlet conduit, thus stopping the flow of'sewage therethrough to the basin. Should the continued ilow of liquid to the basin through the other inlet conduit and the other by-pass valve result in the liquid level continuing to rise, a second pump is operated. Operation of the second pump automatically closes a by-pass valve related thereto and a check valve in its inlet conduit. However, when both pumps are being operated, sewage may continue to tlow to the basin from the main sewage inlet conduit through a bar box provided therein.

The dual-pump system herein described includes two reverse-flow pipes or conduits in direct ilow communication with a main sewage inlet conduit. Eachpipe has a fitting provided with a by-pass valve and connected to a common conduit, leading directly into the sewage collecting basin so as to permit the free and uninterrupted United States atent O inow of liquid through the inilow pipe to said basin'when 1 both lpumpsare idle. When both pumps are operating to withdraw liquid from the basin, said withdrawn liquid is owed under pressure through the pump by-pass iittings in such manner as to automatically close the -by-pass valve in each fitting and the check valve in each inlet conduit. rl`he liquid is then owed through the reverse-flow conduits in a direction reverse to that of the inflow, and into discharge pipes, one of which is in llow communication wth each reverse-dow conduit, for disposal.

When the check valves in both inlet conduits and the by-pass valves in both fittings are closed by the operation ice of both pumps, the inilow of liquid in the main sewage inlet :line backs up therein and overilows a bar box in lsaid line. The liquid spilling over the weir sides of the bar box is delivered directly into the basin. When only one of the pumps is operating, the-ow from said purmp is through the related by-pass iitting as described hereinabove, and the ow of incoming liquid continues through the vby-pass fitting connected with the pump that is idle. Suitable screens and strainers are arranged in the flow system to intercept sewage solids and thus prevent such solids from entering the basin and being subsequently withdrawn through the pumps.

Chatten'ng of the valve elements in the by-pass valves, `and resultant leakage and loss of pressure in the pump flow, is avoided in the present flow system byjconnecting the by-passI passageway of Aeach valve in direct flow communication with the sewage basin at -a point below the lowest level of liquid therein, thereby providing a water seal for each by-pass valve.

The "structure by means of which the above'noted and other advantages of the invention-are attained will be described in the following specication, taken in conjunction withthe accompanying drawings, 'showinga preferred embodiment of the invention, in which:

-FIGURE 1- is a vertical transverse section view 'of a collecting basin, taken substantially on line i1-1 of FIG. 2, illustrating a sewage pumping apparatus embodying my invention connected therewith, with parts broken away to facilitate illustration;- f

FIG. 2 is an elevational view of the apparatus as viewed from the left side of FIG. l;

FIG. 3 is a -top plan view of the apparatus; and

FIG.4 `is* an enlarged sectional view of `one of the pump by-pass littings. l

Referring now to the accompanying drawings, and -particularly to FIG. 1, there is provided a sewage collecting basin 11, into which sewage for example, is delivered for subsequent pumping to a suitable place for disposal by means of the novel pumping apparatus associated with it. `Sewage or other liquid containing solids, suchas debris, abrasives, etc., enters thelsystem from' an influent conduit external of the structure disclosed, through a main sewage inlet conduit 12. The inflowing liquid passes through a diversion fitting 13, through a pair of

conduits

14, 15, each containing a normally open service valve 16 and a check valve -17, and into reverse ow conduits 1S and 19 respectively. A conical screen 21 is provided in each of the conduits 18, V19 for screening out solids in the incoming liquid owing'through said conduits into valve controlled pump by-

pass ttings

22, 23 respectively. Each of these lay-pass fittings has a leg 24 in direct flow communication with a Y-tting 25 connected to a conduit 26 leading into the interior of the collecting basin 11, adjacent to its bottom. A normally open service valve 27 may be provided in the conduit 26.

The other leg 2S of by-pass tting 22 is connected to the discharge volute 29 of a pump 31, whereas the correspondingleg 28 of by-pass fitting 23 in connected to the discharge volute 32 of a pump 33. These

pumps

31 and 33 may be of any conventional construction, and each has associated with it anelectric or other suitably driven

motor

34, 35 respectively, having its shaft connected to the impeller of the related pump fordriving the same. The suction inlets to said pumps are connected to

pipes

36, 37 respectively, which are in direct flow communication with the interior of the basin 111, also adjacent to its bottom. y Y e As noted hereinabove, when both pumps v131, 33 are idle, inowing liquid passes freely through both

pump bypass fittings

22 and 23, through Y-tting 25 and then into the basin.` The by-

pass fittings

22 and 23 are identical, hence the following specic description of one is duits associated with the pump that is idle.

i l, both check valves and both `(and Vthe Yinflow of liquid through the flow system is equally applicable to the other. As best shown in FIG. 4, pumpby-pass iitting 23 has a valve element 38 `mounted adjacent to the by-pass passageway 39 in plate 41 se- Y cured to the end of its leg 24. The valve element 38 is in the form of a disc having a top wall 42 which seats on o ow from entering the diversion fitting 13. When both a valve seat preferably formed by an annular member 44 -which'is fitted into said passageway, as by a drive tit. The top wal1-42 preferably has a cup shape, and its concave side is .in the direct line of How from the pump when Vthe valve element is in the open position shown.

-The valve element 38 is pivotally mounted along one -ofitssides on a bolt or pivot pin 45 for swinging movernient into open and closed positions. A curved skirt or shroud `portiondt on said valve element overlies a helical spring 47, `which surrounds the pivot pin. Spring 47 has one end 48 anchored in the plate `41 and its other end 49 engaged in an opening 51in the valveV element. `Itv is manifest from the drawings that the shroud 46 protects they spring against the accumulation thereon of any small solids which might pass 'the strainer and thus `is a torsion spring `and it is Vprimarily adapted to maintain valve element 38 in the normally open position shown.` AIt functions Valso as an anti-slam device when the low through the fitting is sharply reversed,v as when theassociated pump is started. Y'

The operation, insofar asthe assembly hasfbeen described, is such that when the liquid in basin 1 1y is at a predetermined low level, as shown Yat 52, the motors and basin raises suciently to cause an enlargement 54 on its `rod 55 to engage and Aclose a normally'open switch 56,

controllingV the operation of one of the pump Ymotors 34 Operation of one of said motors and its pump will, in a'ma'nner to be described presently, cause the related check valve and by-pass valve to close withdraws liquid from the basinand dischanges it at a suitable place Vfor'disposal. However, inasmuch as only one of the pumps is operating, incoming sewage will continue to enter the basin through the systemv of inow con- Should the inilow'of liquid be in excess ofthe capacity of the pump ythat is operating, the level of the liquid will continue to rise in the basin, the float will be raised further and its rod enlargement 54'will then engagel and close a second `normally open switch 57 controlling operation of the secondV pump so as to place said pump in operation. VWith both pumps operating Vto withdrawliquid'from the basin, by-pass valves are closed,

prevent successful operation of the valve. The spring 47 while the pump of these check valves are closed, the inow of liquid vthrough the flow system is stopped, thus causing incoming sewage to back up in the main sewage inlet conduit 12 and spill over the weir sides of a bar box 62 mounted V in said conduits and into the basin. The bar box 62 is stopped. When the yliquid level in the basin recedes, the Y Ypumps passes through .the respective by-pass fittings 22,

23, up through the' strainersY V21, carrying with it the solid matter accumulated around the strainers, and is discharged with the solid matter through respective discharge pipes 58 and 59 (FIG. 2). Ifdesired, a service shut-,off valve 6 1 may be provided in each o f'the pipes 36, 37A.

V The pressure of the pump` flow in the conduits 18 duit connecting said provided with a screen 63 to prevent solids of objectionable size Ifrom passing over the sides 'of the box intov Y basin V11. When the pumps stop, and the sewage resumes its normal ow, the liquid owing through Vthe main inlet conduit carries the solids from the underside'of screen 63 through conduits 18 or 19 Vto strainers 21.

Because of the use of two or Vmore pumps and their related ow systems, the ow capacity and lift power of each pump may be much smallerl than that 'required of a single pump, owing to the periodic operational requirements arising from varying volumes of liquid required to be drawn from the basin. As a result there is less Vwear on the pumps and their motors, Yand maintenance and operational costs are reduced.v Furthermore, the lowest permitted level of liquid in the Vbasin is maintained above Vthe level of the' by-pa'ss valve 'elements s'oas to provide a water seal on the'suction side by Ythe by-pass valves whenptheir related pumps are operating.V reduces Vthe possibility .of valve leakage, valve chatter, and unstable operation of the pumps through loss of pressure on their discharge side. g

Although I have described a Vpreferred embodiment of my invention in considerable detail, it 'willbe understood that the description' thereof is intended toV be illustrative, rather than restrictive,V as many details ofl the structure may be modified or changed without departing from the spirit or Vscope of the invention. Accordingly, l do not desire to be restricted to the exact construction described.

1. In combination, a sewage basin, a'niain inlet conduit bridging the basin, a diversion fitting on said conduit, said'fitting comprising a plurality of branches, a reverse flow conduit in "flow communication with each branch of said diversion fitting, a pump operatively connected to each reverse flow conduit, eaclil of said pumps being Vspaced Ifrom said sewage basinand operable to pump liquid from Vthe basin through its related reverse flow conduit, a motorfor operating each pump, a pump by-pass passageway inl each reverse. flow conduit, a common con.- by-pass passageways with the basin, a valve element in each by-pass passageway, means to hold each `valve element in open position to permit ilow of liquid to the basin through the related reverse flow conduit while the related pump is idle, each of Vsaid valve elements being moved automatically into closed position when the related pump is started, separate norm-allyopen switches for each motor, Vmeans for successively closing said switches in response to rises of the liquid level in the basin, the operation of Yeach pump stopping the ilowof liquid to the basin through its related reversefilow conduit, and an overflow bar box in thejmain inlet conduit through which liquid may spill into the basin when all of the pumps are operating. p' l 2. In combination, a basin, `reverse ow. conduits through which liquid is iiowedin one direction to the basin and in an opposite directionifrom the basin, a pump voperatively connected to eachy reverse ilowconduit and Y passage'ways with the basin, saidV by-pass'passageways and the connectingV conduit being arranged below the lowest liquid level in said basin to maintain kliquid in Vsaid connecting conduit and by-pass passageways at all times, a.

valve element in each passageway, means normally holding said Valve elements in open position to permit liquid ilow to the basin through any' reverse ow conduit when the related pump is idle, said valve elements when in open position each lying in the path of liquid iiow trom the related pump when said pump is operating and being so dimensioned as to be moved by said flow into closed position against the action of said holding means, and means responsive to diierent predetermined high liquid levels in said basin to selectively operate said pumps while permitting liquid to flow into the basin through reverse llow conduits related to pumps not in operation, the by-pass passageways related to said idle pumps, and said connecting conduit.

3. in combination, a basin, a main inlet conduit, reverse flow conduits in flow communication with said main inlet conduit, a strainer in each reverse ilow conduit to separate solids from liquid ilowing to the basin, a pump opera- -tively connected to each reverse ow conduit, means for operating each of said pumps to pump liquids from the basin through the related conduit, said means being adapted to operate any of said pumps individually or simultaneously, a pump by-pass passageway in each reverse ow conduit, a common conduit leading from said passageways to said basin, a valve element in each passageway, means for automatically moving each of said valve elements into closed position to prevent liquid flow through its passageway to said basin when the related pump is in operation, and means for permitting screened sewage to flow from said main inlet conduit directly into said basin when all of the pumps are operating.

4. In combination, a basin, a main inlet conduit, a pair of reverse ilow conduits in flow communication with the main conduit, a discharge conduit in iiow communication with each of said reverse flow conduits, a pump operatively connected to each reverse flow conduit, means for operating each of said pumps individually or simultaneously to pump liquid from the basin through the related reverse ow conduit and to the respective discharge conduits, a pump by-pass passageway in each reverse ilow conduit, a common connecting conduit leading from said passageways to said basin, a valve element in each passageway, a spring operatively connected to each of said valve elements, each of said springs being adapted to move the valve element to which it is operatively connected automatically to open its passageway when the related pump is idle, means for automatically moving each of said valve elements to close its passageway when the related pump is in Operation, said valve elements and said connecting conduit being below the lowest level of liquid in said basin to maintain a liquid seal at each of 6 the valve elements when it is in closed position during operation of the related pump.

5. in combination, a basin, conduits for liquid ilowing in one direction to the basin and in an opposite direction from the basin, a pump operatively connected to each conduit, means for operating any of said pumps individually or simultaneously to pump liquid from the basin, a pump by-pass passageway in each conduit, a common conduit connecting each of said by-pass passageways with said basin, a valve element in each passageway for opening and closing the passageways, spring means connected with each valve element to hold it in open position when the related pump is idle, each valve element when in open position being in the path of liquid ow from the related pump and being so dimensioned as to be directly responsive to said flow to be moved into closed position against the action of said spring means when the related pump is in operation, said by-pass passageways and said connecting conduit being located below the lowest level of liquid in said basin so as to maintain a liquid seal at each ot the valve elements when it is in closed position during operation of the related pump.

6. ln combination, a basin, a main inlet conduit, a pair of reverse llow conduits communicating with said main inlet conduit, a common connecting conduit communicating with both of said reverse flow conduits and said basin for iiowing liquid to said basin, a pump operatively connected to each of said pair of reverse flow conduits, each of said pumps being spaced from said basin and operable to pump liquid through its related reverse flow conduit in the opposite direction, means to operate said pumps individually or simultaneously, a by-pass fitting in each of said reverse ow conduits adjacent said pumps, liquid being adapted to flow from said main inlet conduit through one of said reverse ilow conduits and its by-pass tting when the related pump is idle, a valve in each of said bypass iittings to prevent ow of liquid from either of said reverse ilow conduits to said connecting conduit when the related pump is in operation, and means for flowing liquid from said main inlet conduit directly to said basin when both of said pumps are operating, said valves and said connecting conduit being below the lowest level of liquid in said basin to maintain a liquid seal at each valve in its closed position.

References Cited in the le of this patent UNTTED STATES PATENTS