US2021613A - Pumping system - Google Patents

Description

or other water supply and outlets 4. to which Patented Nov. 19, 1935 PATE ' PUMPING SYSTEM Allen, Gordon. Sheppard, Elmira, N. Y;, assignor I to American-La France and Foamite Corpora-.

tion, a corporation of New York Application January 6, 1933, Serial No. 650,400 I 3 Claims. (01.103-42) The invention relates generally to pumping systems, such as automotive pumpers for fire department use, in which a pump is operated to furnish water underhigh'pressure to anumber of hose lines. Customarily each line terminates in a nozzle furnished with a valve by which the fireman handling it can control the discharge and shut off the water stream, the other lines meanwhile continuing in action. To guard against the pressure increase which would otherwise result from shutting off one or more of the lines and which might raise the pressure at the remaining active nozzles to such a point and with such suddenness as to jeopardize the safety of fireman handling them from a ladder or other precarious footing, it is necessary to provide a relief valve which automatically limits the maximum pressure which can obtain in the high pressure side of the system, thereby avoiding the dangers incident to sudden or undue pressure increase which might result from the foregoing or other causes.

The object of the invention is a compact relief valve which, in its preferred ,form, may be 'readily atttached to the pump or removed from it, as a unit, and which is reliable in action, sufliciently sensitive to allow only a minimum and safe increase above the-normal operating pressure, and

' relatively stable and non-pulsating, the pump being so organized as to facilitate themounting of the unit and, more particularly, serving to cooperate withit to the best advantage and so to position it as to ensure its protection against in jury, while locating it for convenient access to the several unit controls and parts, all as more particularly pointed out below with reference to the accompanying drawings in which:

Fig. 1 is an elevation, partly broken out, of a pump and the relief valve connected to it.

Fig. 2 is an end view of the same, being'a side view as this type of pump is customarily mounted i. e. transversely of thetruck chassis.

Fig. 3 is a section on the line III'III of 1.

Fig. 4 is an enlarged view of the relief valve detached from the pump. i H

Fig. 5 is a section on the line V-V of Fig. 4.

Fig. 6 is a sectionon the line VIVI of Fig.5, and

Fig. 7 is a section corresponding to Fig-.5 but with the parts in a different position.

The pump I will be recognized as a type commonly used on fire apparatus, having rotary impellers 2, intakes} for connection to a hydrant the hose lines are coupled, and while this type withadjacent outlets land Bin the end 9 ojf the pump casing, which is facedQoff to provide 'af'seat for the relief valve structure intermediate the parallel inlet andoutlet passage of the pumpfihe 10 function of the reliefvalve being/to-short-circuit the pump by permitting the water to dis-.- chargefrom passage 5, the high pressure side of 3 the system, back to passage 6, the low pressure side,'in responseto predetermined pressure in 15 the former.

, In its preferred form the relie'fvalve structure is organized as a unit, comprising a hollow body portion l0 (Fig. 5) having an internal dividing wall I I forming high and low pressure chambers, 20 I 2 and I 3' respectively, with outlets l4. and I5 adjacent each other in one end of the body, which is flanged and faced oil to seat on the complementary face 9 of the pump housing to whichit can readily be bolted, to support the entire valve 25 structure, the outlets l4 and l 5'then registering respectively with outlets 1 and 8 As a result of thisconstruction of pump housing flandgrelief valveunit the latter is convenient of access, may be readily applied to the pump or removed from it, and in the latter event a closure plate can be bolted over the seat face 9, thereby sealing pas sages 5 and Gand enabling thepump to be put into service again without delay, or an entire unit may as readily be substituted for the one 35 removed.

The relief valve proper, also known as the churn valve, comprises heads l6 and I1 united by vHead I 6 comprises apiston which, as below described, reciprocatesina controlchamber or cyl-r inder '22, moving to the' left to open port 20 when- 45 ever the pressure on the face of the valve lex-v posed to chamber l2 exceeds-that onflthe back of the valve, that is, in the control chamberZZ, the. pressure in the latter'being "determined. bya

pilot valve controlled by the pressure on'the high to pressure side and adjusted tooprate when the predetermined limit pressure is reached. A spring 2| and a bumper extension'itflserve respectively to cushion and limit the opening of the churn valve. u

The lower end (as viewed in'Fig. 5) of the a seat for a pilot valve housing 23, the face of the housing (Fig. 6) being channelled to provide ducts 24, 25 and26 which communicate respeqtively with the high pressure chamber l2 (through port 21), the low pressure chamber l3 (through port 28) and the control chamber (through port 29). Mounted in a longitudinal bore 30 is a slide valve 3| and opening laterally of the bore are a number of controlports 32, 33, 34, 35 and 36 which are designed to provide commimication vas follows: 32, from the high pressure duct 24 to the end of the pilot valve bore, whereby the pilot valve is forced to the right when the pressure is sufllcient to overcome the resistance of spring 31, the tension of which may be adjusted by the hand wheel 33; 33, from the bore 30 to duct 26 and thence through port 29 to the control chamber 22; 34, from the valve here to high pressure duct 24; 35, from the valve bore to duct 23 and thence, through port 29, to the control chamber 22; and 33, from the valvebore, to the low pressure duct 23. In its normal position (Fig. '5) the pilot valve therefore serves to connect the back of the relief valve (chamber 22) with the high pressure side of the pump and, the area of head I3 subject to this pressure being greater than that of disc I 3, the

relief valve is held firmly against its seat to close in the first of which, as already described, it

serves to maintain the churn valve closed., The second position (which results from movement of the valve to the right in response to excess pres sure) is illustrated in Fig.' '7 wherein it will be seen that ports 33 and 34, which formerly were in; communication (through bore 30) are cut off from each other, so that the high pressure in duct 24 is no longer communicated to the back of the churn valve. In its third position, resulting from continued movement to the right, the pilot valve places ports 35 and 36 in communication and so vents the back of the churn'valve (chamber 22) to the low pressure chamber l3, whereupon the churn valve is opened by the pressure on disc I! and the pressure on the hose lines relievedby the shunting of part of the pump output through passage 5, chamber l2, port 20, chamber I3 and passage ltothe pump intake. As soon as the normal output pressure is restored, the pilot valve resumes its original position. (Fig. 5) under the action of spring 31, in its return movement first shut ting off the control chamber connection to the low pressure side of the system and then opening'that chamber to the high pressure side, thereby balancing the pressure on the ends of the churn valve which is closed by spring 2|. At

no time, therefore, is the control chamber in ly, a tendency to surge back and forth, producing a wide fluctuation of pressure in the hose lines, and, more particularly, a large initial pressure increase which, while not as great as would occur if no relief valve were used, is nevertheless suflicient to constitute a source of danger 5 to the firemen. On the other hand, when the relief valve is controlled as above described, it opens promptly (the movement of the pilot valve from its left hand, through the intermediate, to its right hand position consuming only a fraction of a second) and immediately assumes a relatively stable position, moving back from port a distance determined by the amount of water discharged into the suction side, the distance increasing as a second or third hose line is shut it; off. A pressure rise of as little as fifteen pounds is suflicientto render a hose line unmanageable if the pump is normally delivering at as high as 65 or 70 lbs. pressure and, due to the failure of relief valves heretofore to keep the pressure 20 variation within reasonable limits, it has been necessary, whenever the men were required to handle the hoses from ladders, roof ridges, or other precarious positions, to operate the pump at a pressure fifteen or more pounds below normal, so that even when increased by that amount, the pressure would not be excessive. But with the construction above described, the pressure rise which results from the closing of a hose line is so slight (about 7 lbs. with the pump discharging 640 gallons per minute at 80 lbs. pressure) that no such allowance need be made and maximum efllciency may be maintained at all times.

The churn valve is also subject to manual control and to this end a shaft 40, carryin a cam 4|, is mounted transversely of the valve and intermediate its heads i6 and H, the shaft passing between the cage bars i8 which are so spaced that the valve clears the shaft throughout normal, automatic movement of the former. One 40 end of shaft 40 is extended, through a stumng box 42 (Fig. 4) to the outside of the valve body and there carries a control handle 43 having a spring latch 44 engageable in one or another of the notches in quadrant 46, the handle normally 45 occupying the position indicated in Figs. 2 and 4 and the cam 4| the position shown in Figs. 3 and 5. When the handle is swung to the left from the position shown in Fig. 2, shaft 40 is rotated and cam 4| moved to the left hand position indicated in dotted lines in Fig. 3, engaging the inner face of head It and moving back the churn valve to open port 20. When latch 44 is engaged in the notch marked "open the chum valve is therefore locked in such position. When the handle is swung to the right from its Fig. 2 position, the cam is moved to the right hand dotted line position of Fig. 3 in which it engages an abutment 41 on the rear face of head l'l, obstructing movement of the valve from its to closed position, if it is then closed, or -moving it to its, closed position if it is open. When latch 44 is engaged in one of the notches marked close" the churn valve is therefore locked in its closed position. 7 65 The arrangement of bore 30 and the several ports in the pilot valve housing 23 is such that they are readily guarded against stoppage by freezing by means of a jacket 48 which constitutes the entire outer end of the housing (Fig. 5) and substantially encloses the bore 30' (as indicated in dotted outline in Fig. 4) and is arranged in heat exchanging relation tothe ports and also the spring chamber, the inlet and outlet pipes 49 and 50 serving to connect the Jacket 76 in an engine exhaust or hot water circuit, where v by the entire housing can be readily heated. I claim: r

1. The combination with a rotary pump hav-' ing' a suction intake and a discharge outlet dis' 'pos'ed one above the other in parallel relation,

of a seat face intermediate them, adjacent outlets in said-seat face, said outlets communicatingrespectively with said suction intake and discharge outlet, and a removable relief valve unit adapted to be applied bodily to and toengage said seat face and controlling the fiow from the dischargeoutlet to adjacent outlets.

2. The combination with a pump having a horizontally disposed suction intake and a horizontally disposed discharge outlet fOI connection respectively to asource of water supply and hose lines, of a passage opening from said intake,'a passage opening from said discharge outlet, said .passages terminating in adjacent outlets faced ofi to provide a seat, a relief valve unit having two chambers with outlets adapted to register with said adjacent outlets when the unitis applied to said seat, the latter, and the unit-being located intermediate said horizontally disposed the intake by way of said intake and discharge outlet, and'a reliefvalve insaid unit controlling the water flow from one of said chambersto the other.

3. The combination with a pump having a horizontally disposed suction intake and a horizontally disposed discharge outlet for connection respectively to a source of water supply andhose lines, the pump casing being cored to provide passages opening from said intake and outlet and sure chambers communicating respectively with the said adjacent outlets from said passages, arelief valve in its said housing controlling the flow, from the high to the low pressure chamber and a pilot valve in said pilot 'valve housing adapted to respond to predetermined pressure in said high pressure chamber and controlling the movement'of said relief valve ALLEN GORDON SHEPPARD.

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