CA1160319A - Pump failure protection for liquid transmission pipelines - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
When heavy duty electric pumps as those used in muni-cipal water mains and sewage systems are operating, they are working against the static pressure of the lines already full of liquid and usually flowing upgrade from the pumping station for a long distance, to water storage tower or point of dis-charge. This mass of water flowing away from the pump of course has momentum. The outlet of the pump into the main is through a heavy duty check valve to prevent back flow of water from the pipe into the pump. When there is a breakdown of a pump or motor, or less power to the pump when it is work-ing, the sudden drop in pressure in the main with the volume of water in the main still in motion, a shock wave is set up in the pipe line that travels with the speed of sound toward the discharge point or first high point in the line, and it reverses with amplified force back to the pumping station which will open the line to a drain to relieve the force of the returning shock wave. If this valve opens immediately upon stoppage of the pump vast amounts of water will be spill-ed from the system, perhaps with no provision for its adequate disposal. The present invention introduces a time delay relay system at the pumping station that delays the opening of the surge valve for a preset period of time but in advance of the return shock wave that will spill enough water from the main before the shock wave returns to break the force of the returning shock wave to dissipate harmlessly.

Description

Pump Failure Protection for Liquid Transmission Pipe Lines `
S ecification This inven~ion rela~es to the transfer of liquids, most commonly water and sewage lines where liquids in large volumes are pumped from a lower to a higher elevation through relatively S long pipel~nes. In these and other similar systems heavy damage may result where there ls an unexpected power failure or mechanical breakdown of a pump.
Generally, and almost exclusively, pumping systems of the kind to which this invent~on is applicable employ more than a single pump and usually more than two pumps in parallel to meet variable output demands or input supply bu~ keep uniform pressure in the pipeline, which is preferable to a single large pump, but this invention is appl,icable to systems having one or more pumps.
The expression "last pump" in the case of a system having only one pump will apply to the single pump, and also the use of the plural "pumps" may mean such single pump.
Where the system is operating normally and for some reason the pump or the last pump stops, there is an initial drop in pressure in the pump header as the lar~e volume of liquid ~ ahead continues to move through the pipe but the loss of pressure sets up a shock wave that travels throu~h ~he lIquid at the speed Oe sound ln water, that is, around 4000 Eeet (1200~ meters) per second. Reachin~ Lhe remote termi,nal of the pipeline, a pressure wflve rcturns, oEcc~ ~f destructive orce, whtch may clama~e the ~S pipeIlne nncl its supparts ar break ~he pumps~ For thls reflsan It ls the usu~I pr~ctice to cannect a surge vaIve inta the header at i~ 33~

the pumping station arranged to open when such failure of the pumps occurs.
Generally, a surge valve has a valve closing the inlet to the valve caslng while the c~sing has a normaLly unrestricted ou~let. The valve element is sli.dable in the valve chamber wi.th its end remote from the seat of larger area than its seat on the inlet 5 this end of lar~er area belng exposed to the i.nterior of a pressure chamber which also communica~es with the pump header. As long as the pressure in the pressure chamber is equal to the ; 10 header pressure tendi.n~ to open the valve, the valve wi.ll remain closed or seated because ~of the larger area i.n the pressure chamber. If the pressure drops in the header, a pi.lot valve will operate to release the pressure in the pressure chamber to atmospheric pressure whereupon the val.ve will lift from its seat and allow a free outflow of water from the header throu~h the surge valve and pipeline to waste, thereby protecti.ng the pump and pipeline from the impact of the pressure sur~e. Heretofore a : hydraulic pilot va].ve was provided ~o open the surge valve whenthe unscheduLed stoppi.ng of the pumps reduced hydraulic pressure in the surge valve pressure chamber.
A drawback to this arrangement is that in a very long pipeline the hydraulic pilot valve wilL open well before the return surge reaches the pumping station where, in other cases and with shorter pipelines, the surge may return before the hydraulic pressure valve will have openecl sufficiently to effect full opening of the sur~e valve~ or perhaps no opening of the : surge valve will have happened whereupon the surge valve was unprepared to meet the pressure surge in tLme to effectively effect the desired relief~ aLthough a pressure relief valve was 30 also provided.
It has heretofore been proposed to replace the hydrau-llc pressure reli.ef valve above referred to with a solenoid operated reli.ef valve for openi.ng the surge val.ve and to su~stltute a pressure switch th~t will ener~ze the soleno.icl valve to open Eull.y almost instantaneously when the pump d3.s-charge pre~fiure lowers Cl-le to ~udclen ahnormfll shl.ltclown oE pump hut whl.ch, oE cc)ur~e, cloes not happen wJ.th the ~racll.lcll controllecl shut(lown n~ the pump~.

3 i`~

The present lnvention utilize~ such a solenoid and pressure swi.tch but i.n con~unction with a control clrcuit means desi~ned, but not necessarily required, to be contained within a sin~le conveniently located box or housing and arranged to anticipate the pressure surge and assure the surge valve bein~
open at the required time and to effect gradual closi.ng o~ the surge valve a~ter a predete~mined~time interval adequate for the surge valve to have relieved the pressure surge. This control circui.t means is energized from:the same power source as the pumps but includes a b~ttery ~hich functions if the power to the pumps fails, utili.zing`a::uni~que ba~tery charging clrcuit with a nickel cadmium battery~and~'~a battery condi.tion indicator that will keep the operator~'lnormed ~5~ to the battery and charger condition and even pr~vide~'warning'sf a blown fuse or defective circuit or battery. Adju~able.time delay relays i.n the circuit sequences operations, as~..h~reinafter::described ln detail, and in such manner that aft~r-.thèré:ha~b~en an operation of the surge valve and the circuit~ s~ bout to re-arm itsel for the next emergency, and wlth the re~storation of power to the circuit, only a light emi.~tin~ dlode'~on~'~.th~':battery conditi.on indicator will show a light, ~: If, at thls time, the pressure swltch or th~.sur~e~valve sh4uld be closed but no pump should be operating, an~mber panel light wi.~l start flashin~. If now a pump is started, the amber panel l.ight will stop flashing and remai.n constantly lit;.'~
The starting o'.the~pump or pumps will result in the first time delay relay `star~lng:~to run. At the preset time interval a con~rol relay'~will~de-energiæe the amber panel. light and a green panel li~ht will be steadily l.it. The elap~d time to this point will ordinarily delay the li~htin~ of the green light for sufficl~nt t~me th~.minor startup pulsations which could result ln opening the presæure switch (which will previously have been closed by ehe head of waCer ~emaining in the pipeline after the brief opening of the- surge valve) wi.ll be inefective to cause a sur~e valve openin~'. Usually a timer allowi.ng a periocl up to 300 seconds wi.Ll be ad~qua~e for this startup.
The "tlmin~ outl' o tho ~irst ti.me delay reluy at this poLnt es~abllshes a clrcuit tc~ ~a s~cond ~ime dela~ relay which Ln lts Ini~:l.al. concll.ti.on wi.~l have n~ lmmeclinte eE~ect, but IE thcre ~ 3_ :: .

i.s a power fai.l.ure or an opening of the pressure switch for some other cause, the first tlme delay relay loses its ground or negative circuit, establishing a circuit through the solenold switch to cause opening o the surge vaLve, extinguishing the green panel light, li~hting a red panel light warning that a pressure surge is to be anticipated and setting in motion ti.me delay relay No. 2. This assure~ that the surge valve will remain open for a predetermined period of time. At the end of this time, time delay relay No. 2 will de-ener~ize the circuit completely.
This will also open the circuit to the control relay which, however, will not occur :immediately due to an off-delay device including a capacitor that will delay such opening of the circuit for perhaps 30 seconds.
Provision is made for manually closing the valve from the outlet header of the pump to the surge valve and a push button switch, in series with the pressure switch may open the circuit as if the pressure switch had opened and thereby put the circuit through a test run,~which will even trip the solenoid valve switch and open said valve and also test the panel light sequence.
The inventlon~ fur~her provides a solid state flasher circuit and unique solid state battery condition indicator and battery charging circuit.
In the accompanying drawings showing one preferred embodiment of our invention with a solid state circuit capable of being contained, if desired, in a single enclosed metal box:
Fig. 1 is a more or less schematic view of pumping stati.on surge valve and controls, wi.th a multiple pump arrange-ment;
Fig. 2 is a block diagram of the various circuit components;
Fig. 3.i.s a schematic solid state circuit diagram wlth certain duplications of some elements to nvoid confusing cross-wiring;
Fi~. 4 is a schematl.c circuit cliagram o~ the power supply cJ.rcult;
Fl~. 5 J.s a schematic view o~ ~he Insher c:lrcuit;
F:l~. fi :I.s fl sch~matic vlew o~ the "O~ l.fly"; ~nd Fi~. 7 is a schematic view of the "Battery Condition Indicator."
Fig. 8 is a fragmentary detrail view for use in 8 pumping station with a check valve in the pump outlet and means to prevent closing of the surge vaLve before the check valve has closed.
Fi8. 9 is a circult diagram similar to Fig. 3 but with one timer having a circuit arranged for long pipelines between the pump and the discharge ~erminal.
Fig. 10 is a schematic view of a compound switch arrangement for use with Flg. 10.
In the following description all reerence charac~ers preceded by the capital letter D reier to diodes which are con-ductive in the direction of the pointed electrode or arrow. All relay contacts are indicate~ by parallel lines, but where the contacts are closed when the circuit is ready for start-up, they are crossed by a diagonal line. To dist~nguish from capacitors, one of the two confronting lines of a capacitor Ls slightly curved. Time delay relay terminals for the number 2 time delay relay are designated TDK 2 followed by a circled number, as TDR 2 , where the circled number ls a manufacturer's designation, whereas reference numerals ha~ing no circle are in the tradi-tional deslgnation where an uncircled reference character is an arbitrary designation. In some cases, to avoid complexity of circuit lines, the same part, as for example TDR-2 ~ , wilL
appear at different locations in the diagram. This is understood in solid state circuit diagrarns.
Also in this application, reference to operations relates to abnormal conditions, such as mechanlcal breakclown or loss of power to the pumps, and not to the normal shutdown of a station where the shutdown is controlled in such gradual manner as to avoid surge produci.ng conditions in the pipeline.
Referrin~ first to Fig. 1, there is here schematically shown a surge valve installation for fl purnping station having one or more electrically driven pumps P. In the dia~ram three pumps are indicated, all dlscharging liquicl to be transported to a common heMcler. Dependlng on the demands oE ~he system, one or more pumps flre normaJIy operatin~ to Eorce li quLcl ~rom a source o~ supply, not InclicA~ecl, in~o ~he hea(ler ~o erl~er the plpe ~ ~V 3~

throu~h which the li.quid will ultimately be conveyed to a remote polnt oE discharge elevated above the l.evel of the pumping station.
The surge valve itself i.s a known and widely used S devi.ce hsving an inlet A which, in this instance, i.s connected to the header through a manually operable shutoff valve B. The inlet opens into a chamber C with an outlet D. A valv.e element E is arranged to open or close the inlet A and the upper end of this valve element is located in a separate chamber F, the valve having a sliding fit in the body of the valve. The upper end of the valve element has a larger effective area than the lower end.
: Fluid from the header enters the chamber F through pipe G and needle valve G' and, as long as the pressure in the upper chamber lS is as great as the pressure in the i.nlet A, the differential area will keep the valve element seated and the valve will remain closed. If the pressure in chamber F drops below the inlet pressure under the valve element E, element E will be llfted from its closed position, opening the inlet to flow freely through the valve body to the outle-t~
As lon~ as one pump is operating, normal pressure will prevail ln the header; but, if there be but one pu~p or any of a multiple number of pumps stops under abnormal circumstances as previously explained, there wi.ll be a drop in pressure in the header which will close a cireuit through which the solenoid valve J will be energi~ed to relieve the pressure in surge valve chamber F to open the surge valve, and if there i.s an over-pressure in the header, the overpressure valve will be directly opened by the opening of overpressure valve ~ to relieve the pressure i.n chamber F.
The needle valve G' provides for the gradual restora-tion o pressure ln chamber F when normal condi.tions return.
This invention is primarily concerned with the electri-cal equipment involved in operation of the solenoid valve J, the startup and operation of the pumps, the overriding of the operatlon o~ the solenoi.d when, after an abnormal or unscheduled shutdown o the pumps, operation i.s restored and incli.cating the condlti.ons of the control ci.rults at all ti.mes, inclu(ling delayed openLng o~ ~he surge valve for a pre~et time, givi.nR of advance l~o warni.rlg that the c-J.rclli.t l.s prepared or armed ~o e~Eec~ delaye(l opening, and other features, as will hereinafter appear. The electrical equipment is especially designed to be incorporated in a single wall mounted box as a single uni-t but may be divided into sections, some of which would be housed separately from others and interconnected. In either case, this equipment will be hereinafter referred to, both in the description and the claims, as the "box." The box need not be in immediate proximity to the pump itself but located at the attendant's station which is usually nearby, but it may even be somewhat re-motely located from the pumps; but preferably, though not nece-ssarily, it is where an attendant can have ready access, in case of need, to the pump, and the box is connected to the power supply lines to the pump or pumps in the immediate vicinity of the pumps, that is, assuming the pumps to be electrically driven.
Fig. 2 is a block diagram of the box in which each block contains equipment, as indicated by the printed legend in the block. The box operates from a standard 120 volt, 60 cycle alternating current (AC) power source, which in this case is common to the power source for driving the pumps of the pumping station. The "Battery Charger" converts the AC to 24 to 34 volt direct (DC) current and supplies it to the storage battery, which is desirably a nickel cadmium battery that "floats" or is at all times connected across the battery charger output lines. The square marked "BATTERY COND" controls the selective operation of red and greed indicator lights, as hereinafter described.
The following block marked "Mode" includes a manually operable switch which selects which of two procedures is the better suited for a particular station or under some certain condition. There follows a flasher unit that is energiæed under ccxkain cond:itions only when a Elashin~ gxeen or amber light should be ~lispla~ed by elec-tric lamps ~,~ or Al~ in the uppex righ-t corner o~ khis ~i~uxe. Nexk ~o the ~lashex khexe 1~ an "~EE

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Delay'` relay ~hove which is ~elay CR l. To the let o~ CR-l there is a fi~st time delay relay TPR 1 and above this is TDR-2 .
T~R~2 is the last o~ the several blocks in the dia-gram but it will be observed that out o TDR-2 are two lines 5 and 6 which are the box terminals of lines 5 and 6 of the solenoid valve J of Fig. 1. Also to the left of TDR-l are lines 3 and 4 these being the box terminals of lines 3 and 4 of the pressure switch PS of Fiy. 1. There are two other terminals 7 and 8, these being the terminals of the power supply lines 7 and 8 of Fig. 1.
While designated as power supply lines, they are actually lines to the starter switches of the pumps P~ but since they open when a pump stops and are closed when a pump starts, they may be referred to as power indicating lines or auxiliary motor starter contact lines.
Coming now to the explanation of the actual circuit, the first two blocks of Fig. 2 are combined in the square marked "Power Supply" in Fig. 3, the 120 volt AC input lines of which are designated 120 AC. The positive 24-34 volt DC output is designated by line 10 that extends from the positive terminal of the power supply downwardly, then across the diagram in Fig. 3 and then up to the positive termlnal of the battery. A fuse is indicated in line 10 at lOa close to the battery. Line 10 also includes diode D-13, which allows the flow of direct current through line 10 toward the battery but not in the reverse direc-tion, that is, from the battery back to the power supply. It may be here pointed out, since the circuit includes a mulptipli~
city of diodes, the "point" o~ the arrow indicates the direction of current 1OW, but that current may not flow in the reverse direction, this bein~ the common practice ln the diagrammin~ o~
solid stat~ circuit~, The negative terminal oE the DC power supply i~ ind;Lcated hy the conventional cJround indication, and there is a return line ~rom ~he nec~a~ive pole of the battcr~ ~nd ~ - 8 -line 12 to ~xound, ~ indicated at 13.
A branch line l~ le~ds from line 10 at point l~a between diode D-~3 and the battery and te~minates at relay contact 15 of the control relay CR-l, the outline of this relay being indicated as a block in Fig. 2 and in broken lines in Fig. 3.
Contact 15 is open at this point. Opposite or above contact 15 there is indicated another pair of contacts 15' of a single pole, double throw relay which are never used. It has previously been explained that throughout ~he diagram the contacts indicated only by spaced parallel lines are open, but they are closed when crossed by a dia~onal line.
There is a branch line 16 leading from the positive side of the power source of contact 17 of time delay relay TDR-l ~also outlin~d generally as a rectangle in broken lines). It is a standard piece of equipment available as an off-the-shelf item and per se is not~of our invention. It may be purchased, for example, from TKS Engineering Company of Mennetonka, Minnesota.
In addition to contacts 17, this relay has contacts 18, 19 and 20. The timing circuit represented by 21 is the relay coil, and ther~ is a one-way shunt circuit with diode D-22 across its term-inals. There is a positive biasing voltage connection leading from the positive side of the power source through line 23 in which is resistor 24 to the base of a transistor 25 conventional-ly indicated with a base, a collector and an emitter.
As here diagramed, the emitter of the transistor leads to mode switch 26 that connects to both one side of the coil 21 of the relay and the input side of diode D-22.
To explain ~urther what may be termed the ~ositive (-~) energized there is a branch connection 27 from line 10 between the bat-ter~ and the ~ower sc)urce with one lead 23 le~~ing -to terminal 7 o~ th~ pump circuit, as ex~lainecl in Fiy. 1. Another lead from 27 i9 connection 2~ includin~ diode D-30 leadin~ to the _ g flasher pQrtion o~ the app~atus, ~hich in Fi~. 3 is xepresented by the block marked "~L~HER," an o~posite terminal of uhich connects th~ou~h .~ine 31 to ~round or negatiVe at 13.
A l~ne 32 leads from the flasher to connector 33 having a branch 34 leading through contacts 35, here indicated to be closed, to conductor 36 leading to one side of an amber light 37.
Another pair of contacts leading from flasher connection 32 and the other branch of 34 is indicated at contacts 38-39 in line 40 connected with one terminal of a green electric lamp 41.
Another element at all times included in the circuit is the battery condition indicator unit 42 connected at one side to connection Z and the other side to ground through TDR-2 contacts 10-14 and by which red and green light emitting diodes (LED), generally designed for mounting on the door of a box, are ener-gized, these being separate, of course, from pilot lamps 37 and 41 and also the red lamp hereinafter referred to which are also, but not necessarily, mounted on the door of a box.
Further considering Fig. 3, the principal negative side of the circuit, starting with ground 45 at the right of the diagram, this part of the circuit comprises TDR-2 closed contact 46 across terminals or pins 14 and 10 across normally closed push-button circuit testing switch 47, across pressure switch contacts 3 and 4, here shown in closed position, to line 48 with a branch connection to the other terminal of amber light 37 and another to the second terminal of green light 41. Line 48 then extends to branch 48a which includes diode D-49 connected with the emitter of transistor 25. ~nother branch of 48 leads through connection 48b to the open terminal of mode switch 26. Line 48 also extend~ throu~h lines 48c includin~ resistor 50 that balances s:irnilar resisto~ 2~, both circuits thus lead.in~ to -the base oE
transistor 25.
At this point, conslcleratioll may b~ cJ;iven t:o the opexation o$ the circuit. Assu~ing the pump or pumps to be dxiven from a usual ~C current source, then, for the box to be-come armed and initiate the timing sequenc~, 120 volts ~C must be supplied to the input lines of the power supply, and in the case here shown, this should be derived from a power source com-mon to that which drives the pumps, or in some cases just one pump, at the pumping station. There should be sufficient pressure in the manifold by reason of the back pressure of liquid still remaining in the pipeline after closing of the surge valve to close contacts 3 and 4 of the pressure switch PS and the circuit should be closed across the terminals 7 and 8 by the auxiliary mo$or starting contacts when the pumps are started.
If there is no AC voltage applied to the power input lines of the power supply, there will be no pilot lights operat-ing. If there is 120 volt AC current applied to the power supply input with no closure of the pressure switch, only the battery condition light will light.
If there is 120 volt Ac to the p~r intake terminals and there is a closure of the pressure switch contacts 3 and 4 by reason of the closing of this switch due to the pressure head of undrained liquid in the pipe line, most of which is not lost when the surge ~aæ~e is temporarily open, with no pump running and therefore no closure of the circuit across terminals 7-8, the amber light A will flash intermittently in addition to the bat-tery condition light being on.
If a pump now starts, closing circuit across terminals 7 and 8, the ~lashing amber light will change to a steady amber li~ht. This happens because when a circuit is closed ~rom 7 to contact 8, a ci~cuit is then closed ~rom 8 through line 83, diode D-83 and line 32, thereb~ shunkin~ out the flasher. ~lso at this t.ime ~C currenk i~ then supplied to the -kimin~ cirCuit 21 oE 'rDR-l which provide~ a time delay th~ precludes the possibillty o~

X - 1.1 -3:~
surge y~l~e ~ctuation d~e to ~inor pressure variations during pump Start-up, this circui~t heing fr~m 8 through diode D-51, line 52, line 52a, timin~ circuit 21, to swi-tch 26 which, as here shown, is through transistor 25, diode D-49, connection 48a to ground at 45. When TDR-l has timed out, the TDR-l and coil 21 are enerc~ized, the relay will operate to open contacts 19 and close contacts 20, to then establish a circuit through D-52, line 53, branch 54, D-55 and line 56 to one side of coil CRC of control relay CR-l, the other terminal of which is con-nected to ground line 57, TDR-2 normally closed contacts 4 and 5 through the off-delay to ground. Energizing relay CR-l opera-tes to open its contacts 35 to extinguish the amber light and apply current accross contacts 38-39 to apply steady current to green light G.
When steady DC flow has been established in this way through line 56 to the coil CRC of CR-l relay contacts 38-39 they will remain in this condition unless or until the circ~it is de-energized and it must then be again re-established through the operation of TDR-l, as will only occur with the next open~
ing of the pressure switch PS. The display of the solid green light indicates that the circuit is armed and ready to function.
As long as the pumping station is functioning normal-ly the green lamp will stay lighted. With the mode switch 26 in the position shown and the eoil 21 of TDR-l remaining ener-gized~ no change will occur, assuming of eourse that the battery and charger remain in good condition. However, should there be a power failure to the pumps or should the pressure switch open, or both take place, and the coil 21 becomes de-ener~ized, the proteetiVe sequences will ~e initiated.
The batter~ condition indic~tor, o~ course, keeps the operato~ In~ormed ;LE there i~ a ~atter~ condition at fa~llt.
A~uminc~ ir~ that sw;l-tch 26 is Ln the posltion shown 3~

in Fig. 3, the ci~cuit ~or coil 21 i~ through the transistor 25 to ground ~l~ne 48~. If there is ~ power failure to the pumps, there will also be a power failure to the power supply unit, since the pumps and pcw.er supply derive their current frorn the common source at the pumping station. This then will de-energize line 23 from the pcwer source to the base of transistor 25 because line 23 is not in the battery circuit. Transistor 25 thereupon becomes instantly nonconductive and there is, there-fore~ no conducting ground connection through the rela~ coil to line 48 and TDR-l instantly returns to its normal condition opening contacts 20 and closing contacts l9. CR-l relay is not affected by the power failure, and current will then flow from line 14 on the plus pole of the battery across closed contacts 15, line 53, now closed TDR-l contacts 19 to the upper end 52a of line 52, solenoid valve terminal 5, through the solenoid valve J to ground at terminal 6. Also there is a circuit across terminals 5 and 6 through red light 66 to light said light. As the same time branch line 60 is connected through TDR-2 contact ll and through this relay to ground 61.
The same thing happens if, instead of a power failure, the pressure switch opens, TDR relay 1 loses its ground through the pressure switch to ground connection 45.
Operation of TDR-2 opens contacts 4-5 at the end of its timing cycle to de-energize the coil of CRC o:E control relay CR-l, returning this relay to its original condition, thereby also extinguishing the red light and closing the solenoid valve.
Both. times, as is usual, have a dial (not shown~ to adjust the length of the dela~ and reset themselves after they operate for the next operation at the same dial settin~ until th~ dial sctting is chan~ed. Typlcally, the ~ime delay .relay o~ TDR-l ma.~ bc3 acljusted to r~n~Je ro~ a period of a few ~econds to 300 sccond~, or more, and -the purpose of this delay, a5 pre-,~ - 12cl -3~

viously indicated, is to aYoid surge valve opening with minor surges and pulsations that Qccur during pump start-up.
Time delay relay TDR-2 is set to provide a shorter and more accurately tim0d operating cycle. It may be explained that with an abnormal shutdown of the pumps such as will give rise to a downsurge of water pressure, the shock wave that begins with a drop in pressure in the pump header travels, to the discharge terminal of the pipeline and then returns to the pump-ing station as a pressure surge or backflow of water and, in a long pipeline, this interva~ may be any time from several seconds to minutes. Even the sound of the onrushing surge of water will be clearly audible at the pumping station before its actual arriva~. It is only necessary to open the surge valve for a short period of time preceding the pressure surge valve until after the force of the pressure surge has been dissipat-ed and TDR-2 therefore is set to time the opening and closing of the solenoid valve to meet this schedule, which will differ with different stations, elevation of the discharge above the pumping station, and length of the pipeline.

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Reference has hereto~ore been made to mode switch 26 in the upper :I.eft corner area o~ Fig. 3. It is a manually operated two-position swi.tch, anc~ these positions are usually referred to as ~lode A and Mode B; but, to avoid possible confusion with A and B of Fig. 1, they wi.ll be here referred to as MA and MB. In the diagram in Fig. 3, the switch 26 is in the MB position. If the swi~ch 26 is moved to bypass, the circui.t through transistor 25 and make direct connection with wire 48b to l.ine 48 where coi]. 21 wi.ll lose power only after the openi.ng of the pressure switch to break the battery circuit to ground. Hence, in this setti.ng, a power failure does not directly result in openi.ng the sur~e valve.
If the mode switch 26 is in the MA mode and power failure to the pump~ occurs, the circuit goes i.nto a standby armed condition for about 30 seconds during which the green li~ht 41 flashes, the only circuit at this time bein~ rom the battery into the flasher through switch 15, ~-55, ~-83', through line 32, connector 34 and contacts 39 to green lamp 41. A 30-second armed condition after power failure i.s achieved throu.~h the off-delay unit, the negative charge of whi.ch provides a continuing negative polarity to the ma~net coil of CR-L. If at this. ti.me a pressure sur~e is imminent, the T~R-2 contacts ~ and t~ will close and assure completi.on of a full cycle even if the off-delay time has expi.red. ~ ~
Should no pressure surge occur during the standby armed state, the off delay will cease to maintai.n a negative voltage on the negative pole (upper end in the diagram) of the reLay coil at the end of its deLay peri.od. This removes positive current flow through the timin~ circuitj whereby it then deactivates th~
circuit completely.
ShouLd, however, the circult be armed in either the ~IA
or MB modes and a normal pro~rammed shutdown takes p]ace, openin~
the circui.t across auxiliary motor starter terminals 7-8, the off delay circuit loses posi.tive DC controL voltage and begi.ns its delay period o approximately 30-seconci to a nonconductlng stcltc for removi.ng the negati.ve polarity tsomet:l.mes conveni.ently re-fcrred to AS ~lnegfltLve DC~) to the ne~ative terminal of the reLay coi.l. of CI~L. IE a ~lowllsur~e occur~ dur:inp ~his perlod, the clrclli.t wll.l resl)ond wl.th the instant opening oi the solenoi.(l 3 i'~

valve J, as previ.ously described.-llowever, if no downsurge occurs during this period, aswill hereinafter more fully appear, but with the exceptlon that since the 12Q volt AC current is not interrupted, the amber light will resume fl.ashing, indicating a standby unarmed ci.rcuit condi.tion.
In Fig. 3 it will be observed that there ls a line 65 which comprises a conductor between the power supply and TDR-l.
When contacts 17 close, this conductor supplies current directly to provide a shunt around conductor 26 after contacts 19 and 20 are closed to take care o~ the increased load at this time without~ however, charging the circuit with the battery.
The push button test switch in Fig. 3 is shown in series wi.th the pressure switch and switch 46, for ease of following the overall circui~. However, the diagonal dot-and-dash line positions it near the lower center of the dia~ram. Testing of the circuit may be efected even though the pumps are not operating in a normal manner and the circuit i5 not armed.
For ease in following the test operation, the reference numerals will be marked with a prime t') for followin~ the test.
Positive ~C is supplied from line 10 and branch line 80' to switch contàcts 81' arranged to bé closed by pressure on push button switch~82i. This will allow posi.ti.ve DG through ~iode D-82 to line 56~, to line ~ to one side of the ~oil CRC of control relay CR-l. From this poi.nt current wi.ll flow thr~ough said coil, line 57~ and off-delay to ground'at.l3. At the sa~e time, current will flow through D-~4' and D.-8,4 causing the off-delay to conduct. This will result.in the openin~ of the surge valve during timi~g on TD~R-2 through the cLosed contact 19 and of TDR-l ~ the operation of the solenoid valve as previously described. At this time, manually operable valve B (Fig. 1) will be opened onl.y slightly to avoi.d spilllng unnecessary amounts o water throu~h ~he surge valve :In thi.s test.
~ D~J
As prevlously stated, the battery is a nickel~cadmium (Ni~d) battery. Fi.g. 4 di.scloses one power supply for this battery, but the invention is not nece~sari.ly restricted to such a power supply. As i.ndicated, the AC :I.nput connecl:i.ons connect flcross the pri.mary Oe a step-down transformer, ~he secondary lQ0 -l4-~`

o whi.ch i.s connected across the input terminflls of a full wave rectifier indicated by the square wLth oppositely directed di.odes leadin~ i.n divergent directions to the positive (~ and negative (-) output terminaLs. Line 101 from the ~ side of the rectifi.er S has two resistors indicated as 2W and lW. TDR-l contacts short out lW when the current requirements of TDR-l and CK-l are added to the output to keep the charging current to the NiCd battery unchan~ed. Biasing volta~e for the transistor 25 i:s provj.ded by the positi.ve half wave positive off-take 23, which is not in the battery circuit.
This circuit is unique in that voltage regulator VR is so connected that current fLowing through external circuitin~
must keep a regulated volta~e across the two load resLstors lW
and 2W. This results i.n constant current charging for the NiCd battery. Closing of normally open contacts 17 of TDR-l shorts out load resistor lW, increasing the current required to maintain the regula~ed voltage across resistor lW.
This arrangement is important in the charging of NiCd batteries which must normally be continuously charged at a generally uniform rate. With the arran~ement here shown, the charging rate to the battery is normally regulated through the two resistors but, i.f the load increases as when TDR-l and CR-l have their coils continuously energized and the green lamp is constantl.y burning one of the resistors lW is shunted out, supplying more current to the load demands without increasing the current suppLy to the battery, which requi.res a constant charging rate.
As here diagramed, 2W and lW are indicated to be of unequal value, but these values wi.ll be seLected according to the requi.rements of a particu1.ar installati.on. While the ci.rcuit here shown is oriented to Fig. 3, it wiLl be understood by those skilled in the art that it will be applicable to other circuits employin~ the same type of NiCd battery or constant current requirements.
The Flasher I ~
Conventi.onfll fLasher circui.ts o vari~-ls types may be uscti, such n~ maRneti.c on-o~E swi.tches, ~herm~l. on-oEE switches but, ~or compnctness, li~htness and absence oE heacing elements, but the si.mpl.e ci.rcuit shown in Fi.g. 5 has proved most satisfactory.
When positive DC current is app:Lied to li.ne 29' through either of the diodes D-30 or D-83' ~see Fig. 3), the then discharged 0~2 capacitor A-43 in the flash-out circuit A-44 applies bi~s through resistor 220 to the base oi transi.stor A-42 to thereby a~ply voltage through resi.stor 6.8 to the base of transistor A-CJ2. Current then flows from the collector of A-92 to A-44 leading to contact 35 or 39 o~ Ci~-1 to flash either the arnber or green light as the case nnay be. When 0.2 capacity again becomes completely charged, causing transistor A-42 to turn off, in turn causing transistor A-92 to turn off, extinguisi.ng the lamp. The capacitor 0.2 discharges throu~h the filament of the lamp and the 220 kQ resistor to the base of A-42. This results in driving transistor A-42 hard to the cut-off condition, keeping the lamp extingui.shed. When capacitor 0.2 completely discharges, the cycle repeats with a frequency determi.ned by the circui.t components. We prefer about 100 cycles per minute~
The Off Delay (Fi~ 6)

2~ Referring to Fig. 6, poslti.ve current from line 83 (Fi.g. 3? i.s connected through diode D-84 to the 1.me.~ohm resistor and the base of transistor 85 to conduct current to a negative current path which is established throu~h transistor 86 from ground 13 ~Fi.g. 3) to contact 5 of TDR~2. When positive current i.s lost across terminals 8 and 7 due to a power failure or the stopping of the l.ast pump, the 18 mfd capaci~or 88 supplies an "on" bias to keep transistors 85 and 86 conducti.ng for about 30 seconds after which the negative si.de of the ci.rcuit from C~ of TDR-2 to 13 ceases to conduct.
~attery ConditLon Indicator (Fig. 7) In Fig. 3 the b~ttery condition indicator is eonnectecl to the positive l~ne ~ from the power supply and its negative side leads to contacts ~ and ~ oE TnR-2 and g~ound. Its purpose, of course, Ls to Indieate if the ba~tery is fully charge(l and capabl.e o~ operati.ng the sol.enoicl pllo~ val.ve J ~F.Lg.
1) ancl i:he nssoci.ated circuitry. The lndi.cati.on Is shown in recl or ~reen, prefernbl.y on the door of ~he box, 1 e there .Is a single ~c~x a~ l.revl.ousl.y expl.ninecl, or at some associat~tl flr~a where ic Is always vlsl.hl~. Pre~erabiy, a ~rl.chromatic l.i.~h~ em:lc~in~

31~

diode (LED) (Fi.g. 7) suppli.es the indi.cation, i..e., red or ~reen as conditi.ons req~lire. The circuit is desi.gned so that the recl indi.cator appears at all times except when some specific circum-stance prevails, that is, circumstances indicating that the battery voltage cluring constant current char~in~ Ls within certain prescri.bed limi.ts. These limi.ts vary i.nversel.y with the b~ttery temperature. IE these li.mlts are met, the red light is extinguished and the green LED signal. light i.s energized This green ~ED is of course unrelated to ~reen light 41 i.n Fig. 3.
Red ~ED ;s energi.zed throu~h transi.stor 105 from connecti.on Z (Fip. 3) through conductor 106 in whlch are diodes 107 and 108, the emi.tter of 105 connecting to positive line 106 through branch li.ne 109. The collector of transistor 105 is connected through li.nes 110, 11 whi.ch includes resi.stor 112 and terminates at the red LED. The ci.rcui.t from red LED to ground or negative circui.t i.s through ~onductor 113 and TDR-2 ~ .
Red LED i.s biased at thls time through connection 114, in whi.ch i.s resistor 115 which connects with line 116 connecting the collector of transistor 117. Wi.th this arrangement .the red ~ED will never li.ght when the ~reen LE~ i.s t.i.~hted because, when transi.stor 117 i.s conclucti.ng, line 116 chan~es Erom negative to positive, reversing the po:larity of the base of transistor 105.
There i.s a circui.t compri.sing l.ine 118, trarlsistor 119, negati.ve line 120 from the transistor to zener diode 121 and also through branch line 122 wtth resistance 123 to the ne~ative li.ne 109. There i.s thermistor circuit sh~mted around transistor 119 comprisi.ng line 1~41 resistor 125, thermi.stor 126, posi.~ioned physically between the cells of the battery where it responds to battery temperature, and line 127 in whi.ch i.s a 150 ohm resistor 128 and a vari.able 200 ohm resistor 129. A l:ine 130 from the ,'~latter biases the base of ~ansig~or 11~ ancl there i.s a connection 131 with resi.stor 132 to l.i.ne 11~. It wi.ll be notecl thclt transistor 119 :i.s; In efEect, reversed wl.~h respect to the other three transistors (sometlmes referred to as transi.stors 1 to 4 in the:Lr top to bottom order in the cli.agram). This reversal is to mai.ntaln a negfltive potenti.al ~rom ~,ro~lncl t:o chc emi.tter o~ l:L9 to rneet the reverse conclllcti.vLty oE a zencr cli.ocle.
When l:he vol.t~l~e o~ the emltter oE transl.stor 11 reaches ,l val.-le sucll l:hflt the zener dio(le wi ll. concluct, resistcr 132 pUtS suffici.ent nepati.ve bias on the base of transistor 117 througl~ line 133 so that it conducts, li~hti.n~ the green LED and extin~uishi.ng the red, since the collector of 117 which previ.ous-ly was negative now becomes poslti.ve, removin~ the negative bi.as fronn transi.stor 105.
The green light i.ndi.cates the battery vol.tage is normal.
for the temperature of the battery at the cons~ant prevaLLing charge rate. If, however~ the negative blas on the base of the third transistor increase~. sufficiently to bias the base of the third transistor 136 through resistance 135 for an overriding voltage to be appli.ed to line 133 above resi.stor R5, the bias on the base of the transistor 117 becomes posi.tive and ceases to conduct whereby line 116 will again apply a negative bias to the second transistor to again l.i.ght the red LED. Thus there i.s a flip-flop from red on undervoltage, green in the proper charging ran~e and back to red on overvoltage, the green range bein~ a relatively narrow band which indicates the nj.cke] cadmium battery condi.tion as good Çor any given temperature. The thermistor is in physi.cal proxim.ity to the battery to respond to its temperature but electri.cal.ly separate. It responds inversely to a temperature increase so that, as the ternperature of ~he ba~tery rises, the base of transistor 119 becomes increasingly posi.tive through connection 118 and 1313 increasing the ne~ative flow in line 120.
Red on the undervoltage side of green indicates a shorted cell or discharSJed battery and, on the overvoltage, indi.cates an open cell or a bLown fuse. Green spreads over a sLight vari.ati.on Çrom one side or the other of normal indicati.nS7 that the battery and battery circuit are in operati.ng condition and properly charged.
In the fore~oi.ng ba~tery condi.tion :Lndlcator circuit a trichromatic LED ).s preferred to separate red and green light emitting diodes, si.nce in a border zone, when a change from one to the other i.s about to take place, both diodes may be operatin~
and their combined operati.on wiLl prociuce a yell.ow color that will rep].ace the red or green to attr~ct attent:ion to a chan5~i.n), si.tuatlon.
F:l5,. S~ i.s n schemnti.c illustrnl:i.on oi a mocliÇ3cation wherei.n the ~ump clischar~Q ~ystem i.nclucle~s tl check valve chat opells away ~rom ~he ~ rnp i.n~.o t;he pipeline and whlch may sometlmes be open after the surge valve has closed. To prevent closin~ of the surge valve before thi.s check valve has elosecl, the arrangement disclosed i.n this ~igure provi.des a simple solution.
In this modi.fication~ 200 i.s the check valve having a gate 20~ that pivots about a sha~t 203, at leasL one end of which extends outside the casing. The view is an expl.oded vlew where the dotted line indicates the axis of this shaft and on the projecting end of the shaft there is indi.cated an extension or cam 205 which, when the eheck valve is in the elosed position, holds open a microswiteh indicated by a easing 207, and an arm 208 that is raised slightly to the open position when the valve gate ls closed.
When the valve gate i.s even partially open, the extension 205 swings down, allowin~ the microswitch arm 208 to spring down and elose the :switch. Two leads 209a and 209b from the switeh connect across terminals ~ and 0 of TDR-2 (Fig. 3~. If TDR-2 is at that ti.me about to open the cireuit to CRC oE CR-l to close the surge valve by opening the ei.reuit to the solenoid valve, the mi.croswitch then bein~ closed provi.des a shunt cireuit across contacts ~ and ~ so that CR-l does not "know" that the cireuit between ~ and ~ had otherwi.se been opened, and therefore keeps operating to hold the solenoid valve eireuit energized and keep the surge valve from~closing. When the ~ate swings to elosed position, the mieroswitch opens in the manner above deseribed and the brid~in~ of the circui.t aeross eontacts ~ and ~ is removed and the surge valve will close.
The circuit shown in Fig. 9 i.s a modification of Fig.

3, but all e].ements eommon to the two eircuits have like reEerence numerals. This eireui.t ls especlally <lesi.~ned for ~Ise ln pumpin~ stations where the surge vaLve ancl p3pe dischar~e terminal are a lon~ di.stance apart, so that there is a relatively long time lapse between the downsur~e or pressure drop at the pumping stati.on when an abnormal or ~mprogrammeci pump stoppage 3S occurs, anci the tlm~ the resultin~ press~lre sur~,e arrives from the pi.pe terminal to th~ pumpi.n~ statJon may be a period oE many seconds to a~; much as ~wo minutes or more.
In Fl.~. 3, TDR-2 opens Lhe solenoi.d valve to open the 3~

surge vaLve almost instantly for a peri.ocl of tLme selec~ed on TDR-2, nominaLly rom lO seconds to 30 seconds after the pressure drop or downwsurge at the pumping station and then initiates the gradual closing o:E the surge valve. 1lowever, with long pipelines, the opening of the surge valve should not occur until a few seconds before the arrival of the press~lre wave or surge at the pumpi.ng station, 60 that excessi.ve amounts of water or other liquid would not be drained from the line during that period.
In Fig. 9 there is shown a modifi.e~ TDR-2 type relay with an added set of contacts which will close so~etime following the initiation of the operatin~ time of the relay and the expira-tion of the period over which it is tirned to run, and the circuit in Fig. 9 with the compound series of two switches that may be used to accomplish our pu~pose, that fs, start the running o~ the lS time relay in its scheduled sequence but delay opening the solenoid valve to start the opening of the surge valve at some definite time perj.od thereafter.
In Fig. 9 the TDR-2 relay is here shown with contact in series with ~ through a normally closed switch as diagramed.
The switch contacts, shown at TDS ~these being the initials for time delay switch) are in series with 5, leadi.ng to the solenoid valve, as does the numeral 5 in Figs. l and 3. The numeral 6 is the return line from the solenoid switch to ground, as in Fig. 3.
There is a diode D-90 between 5 and 6 and in series between this diode and 6 there is a red light R corresponding to 66 in Fig. 3.
However, there is here included the flasher as in Fig, 3 through line 32A, TDR-2 contacts ~ and ~ ~whch are normally provided on these relays but not used, and therefore not shown in Fig. 3~, and line 3~ so that when TDR-2 starts timing and beore TDS
contacts close to 5, the light R will flash red" indicating the delay time before the surge valve opens by closing of TDS. Duri.ng this flashinr~ iod, diode D-90 blocks the positive flashing to the solenoi.d valve terminal S. When TDS contacts close, energiz-ing solenoid valve diode D-90 conducts positlve to lLght the red li~ht continuousl.y during the time the va1.ve is open.
In Fi.g. lO, a manually ad~ustat~le electrical:Ly operated ~i~ncr compr~ e~ 9wltch rr~s. r~R-2 determlnes tha overall running ~ime L~PSQ ~rom It5 be~linning to the tlme i.t rcaches its "of"
condl.tlon. I`he tlmer X wlll. be ~at to c:Lose th~ cLrcul.t betwaeo TDR-2 and the o~f time of TDR-2. Therefore, even though T~R-Z is running for the overa'l.l ti.me from i.t start with cLosi.ng of TDR-l contacts 19, the circuit to the sotenoi.d va].ve wi'll he closecl onLy when timer ~ starts running unti.l TDR-2 runs out.
Conclusi.on As prev;.ously pointed out, the herei.n de~cribed ci.rcuit is capable of operating in either of two rnodes, to be selected by the operator by manual. operati.on o ~he rnode switch accordi.n~ to the requi.rements of a parti.cular installati.on. The MB mode pro-vides surge valve actuation on each power failure or pressure switch actuati.on any time the circui.t is armed anti for a time peri.od of 30 seconds after the last pump i.s shut down.
The MA mode provides for surge vaive actuation with ~n openin~ of the pressure swi.tch only any t3.me the circuit is armed and for a time peri.od up to 30 seconds after the tast pump is shut down. It is desirable where a power failure may be of a character where r,o si.gnificant downsur~e will fol].ow. For exam-ple, if there were a power ~aj.lure to a single small pump in a lar~e pumping stati.on, the pressure switch might not respond because the effect would be too small to produce a surge, even if at the ti.me of the power failure, the demand at the output would require no other pumps to be operatin~ and this remai.ni.n~ smal]
pump would be the l.ast pump to operate.
Briefly summari.zi.n~, the i.nvention prov;des a compact soli.d state ci.rcui.t for use i.n a pumpi.n~ station as described, wherei.n an operator at a glance can be aware of the condition of the surge control system and is ~iven advance warning of condi.ti.ons whi.ch may be expected to produce a pressure surge of potenti.ally destructive character and open the sur~e valve sufficientl.y i.n advance of the surge, but not so prematurely as to spill excess}ve quantities of water beore the actual sur~e takes place. It pr.ovi.des for re-a-rming itsel-' after the surpe has passe~i and normal condi.ti.ons are restored, i..e., AC power, normal pressure, pump startecl, and the ~nventlon .i.nEorms the operator of when the ci.rcuit i.~ i.n concl-iti.t~n to sa.i~el.y react-ivate the pumps hut preventC3 opern~.ion of the sur~c val.ve in a preset ti.me perlo(l. 'iiwo manunlly acljustcqble tl.me clelaY relnys nncl a sinRIe cl.rcult rel.ly are uncler the cont.rol of ~ne or tht.~ other time delny relny.q. ~lo(le sel~ction prc)vi~le~ l'or ti~o a~laptnti.c)n oE n single un;.t or box to different pumping station requirements most likely to be encountered. Overpressure c:ondltions are taken care of in the usual manner wi.thout lntervention or operatLon of the present circuit or box.

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Fox use with a pumping station having at least one pump driven from an AC power source which operates through the closing of an auxiliary electric motor circuit and wherein the output of the pump is against the resistance of a flow of liquid through a pipeline to a discharge at a remote location higher than the pump so that, if output pressure at the pumping station fails to sustain the required line pressure there may result a pressure surge of liquid in the pipeline of potential-ly destructive magnitude and wherein there is a surge valve in close proximity to the pump operable to release liquid from the line to reduce the force of the pressure surge, the apparatus comprising: (a) a pressure switch responsive to a drop in pres-sure at the output of the pump, the abnormal stoppage of which may result in a pressure surge; (b) a solenoid valve operable upon energizing the solenoid to effect the opening of the surge valve; (c) a relay controlled DC storage battery circuit with a power source energized from the AC power supply to the pump including the pressure switch which is opened upon such drop in pump pressure and produces conditions to initiate the open-ing of the solenoid valve and thereby open the surge valve; and (d) means in said DC circuit to thereupon energize the solenoid valve within a preset time interval following the opening of the pressure switch.

2. The apparatus defined in claim 1 wherein there is a selectively operable means arranged to energize the solenoid valve upon any abnormal opening of said auxiliary electric cir-cuit to the pumps even though said pressure switch may not have opened.

3, The apparatus defined in claim 1 wherein the DC
circuit includes means whereby the circuit will be de-energized to close the solenoid valve and preclude any repeat opening thereof for a predetermined time interval beginning only after at least one pump is restored to operation.

4. The apparatus defined in claim 1 wherein said DC
circuit includes a first time delay relay adjustable within a predetermined time range, a circuit control relay that is intial-ly energized through the operation of said first time delay relay and which, when operated, remains in the attitude to which it was operated by the first time delay relay so long as at least one pump in said pump operating electric circuit is work-ing, and wherein a second time delay relay is energized by said circuit control relay upon the said circuit control relay being operated through its being so energized from the first time delay relay.

5. The apparatus defined in claim 1 wherein said DC
circuit includes a first time delay relay adjustable within a predetermined time range, a circuit control relay that is in-itailly energized through the operation of said first time.
delay relay and which, when operated, remains in the attitude to which it was operated by the first time delay relay so long as at least one pump in said pump operating electric circuit is working, and wherein a second time delay relay is energized by said circuit control relay upon the said circuit relay being operated through its being so energized from the first time delay relay and wherein the de-energizing of the DC circuit by the second time delay relay includes an off-delay circuit for the second time delay relay which comprises a first transistor with its base connected into the output of a condenser which is posi-tively charged during the time a pump is operating, and a second transistor, the base of which is biased from the output of said first transistor to delay the effect of de-energizing the second time delay circuit for about 30 seconds after the circuit to said second time delay relay is opened.

6. The apparatus defined in claim 1 wherein said DC circuit includes a power source in which power line voltage is converted to a battery charging DC voltage and the said power supply is connected across the terminals of a battery to con-tinuously trickle charge the battery and wherein, when no pump is then running, said DC circuit relay is connected to one terminal of the battery through a flasher and said terminal then connected through an amber light to the grounded negative pole of the battery through the pressure switch to indicate that the circuit is ready for pump start-up.

7. The apparatus defined in claim 6 wherein the closing of said auxiliary electric motor circuit is arranged to energize the DC circuit to shunt out the flasher and provide a continuous flow of DC current to the amber light.

8. The apparatus defined in claim 7 in which a first time delay relay is included in said DC circuit and energized for a preset time and the DC circuit is so arranged that when the preset time has expired circuit control relay will operate to extinguish the amber light and energize a green light, indi-cating that the circuit is armed and prepared to respond to a pressure surge.

9. The apparatus defined in claim 8 wherein the open-ing of the pressure switch in anticipation of a pressure surge will deactivate the first time delay relay and energize a second time delay relay from the circuit relay and simultaneously close a circuit to the solenoid valve to energize and open said valve to initiate opening of the surge valve and light a red indicating light after which the circuit relay will return to its initial condition, extinguishing the red light, but the circuit for said amber light is thereupon in series with the now open pressure switch and the cycle beginning with the flashing of the amber light will repeat unless or until a pump is in op-eration.

10. The apparatus defined in claim 1 wherein there are means energized from said power source but independent of the battery circuit for operating the solenoid valve independent-ly of the pressure switch upon failure of the pump supply vol-tage and for rendering the DC circuit ineffective to repeat operation of the surge valve until operating voltage has been restored to the pump.

11. The apparatus defined in claim 10 wherein the battery circuit includes a transistor with a base electrode that is conductive only when the base electrodes is energized from said independent DC source.

12. The apparatus defined in claim 11 wherein there is a battery condition indicator that discloses if the power to the pump circuit is off or on.

13. The apparatus defined in claim 12 wherein there is an intermediate relay effective between the first and second time delay relays and signal lamps in the relay and DC circuit including the battery comprising: (a) a red lamp and means for energizing it when the second time delay relay is prepared to open the solenoid valve and remain so until the solenoid valve has again been closed; (b) an amber light and flasher circuit therefore which is operable when there is AC power available to the pump means but before start-up of the pump means; (c) means for shunting out the flasher to continuously light the amber light when the pumps are running for a pre-determined time interval; and (d) means for extinguishing the amber light when the first time delay relay has timed out and lighting the green light which thereafter remains lighted so long as the pressure switch remains closed and is operating normally.

14. For use with a pumping station having means wherein the output of the pump is against the resistance to the flow of liquid being pumped through a pipeline to a place of discharge at a remote elevation higher than the pump so that, if after the pump is in operation the pump pressure falls, except through controlled shutdown of the pump means, to an extent that may result in a pressure surge of liquid in the pipe-line of a potentially destructive magnitude and wherein there is a surge valve near the pump outlet operable to release liquid from the line and reduce the force of the downsurge, the apparatus comprising: (a) a pressure switch and circuit control-led thereby responsive to pressure at the pump outlet which is closed under conditions of normal operation and a circuit which will open upon an abnormal reduction in pressure at the outlet of the pump means into the pipeline; (b) a DC circuit with a storage battery and a power source energized from an external current source and which circuit includes said pressure switch;
(d) means including first and second time delay relays, the first of which is arranged at all times to maintain normal opera-tion of the pumps as long as the pressure switch is closed;
(e) said first time delay relay also being arranged so that upon opening of the pressure switch, operation of the second time delay relay is effected; (f) a third time delay means interposed between the first and second time delay relay for use in long pipelines to delay energizing the second time delay relay for a predetermined time interval between the operation of the pres-sure switch and the operation of the second time delay relay whereby the surge valve opening is delayed until the downsurge in the pipeline is close to the pumping station; (g) said second time delay relay being arranged after a predetermined time to energize said solenoid valve to effect opening of the surge valve for a short time interval adequate to release a pressure surge which follows the opening of the pressure valve or AC power failure and then close the solenoid valve and when AC voltage for operation of the pump means is again available to restore operation of the pump means; and (h) said first time delay relay being arranged to then maintain the pump means operating and for a predetermined time interval to maintain such operation of the pump means and prevent start-up pulsations in the discharge from the pump means into the pipeline from effecting the pres-sure valve and thereby prevent opening of the solenoid valve from such start-up pulsations.

15. For use with a pumping station having pump means comprising at least one power driven pump wherein the pump operates against the liquid pressure in a pipeline between the pumping station and an outlet remote from and at an elevation higher than the pump so that, if there is an unscheduled drop in the output of the pump means that may result in a downsurge of potentially destructive magnitude and wherein there is a surge valve at the pumping station upstream of the pump means.
designed to open in the event of a downsurge to exhaust liquid from the pipeline to relieve the force of such a downsurge, the invention comprising: (a) a pressure switch which monitors the pump outlet pressure and responds to a drop in outlet pressure such as might induce a pressure surge; (b) a solenoid valve arranged to effect opening of the surge valve when it is ener-gized; (c) a relay controlled DC circuit comprising a storage battery and including the pressure switch and solenoid valve so arranged that an unscheduled drop in pressure in the pump outlet energizes the solenoid valve to effect the opening of the surge valve; (d) timed relay means arranged to effect closing of the surge valve after it has been open for a predetermined time interval sufficient to relieve the downsurge but avoid unnecessary dumping of liquid from the pipeline after the down-surge has been relieved; and (e) means in said circuit to pre-vent repeat operation of the surge valve after it has been closed and until predetermined pressure has been restored to the pump outlet,

16. The apparatus defined in claim 15 wherein the pumps are electrically driven and the DC circuit and storage battery is energized from the current supply to the pumps.