US2608477A - Automatic control of inspirators for gas plants - Google Patents

Description

D. W. SHAEFFER AUTOMATIC CONTROL OF INSPIRATORS FOR GAS PLANTS Filed Nov. 5, 1947 m m" M W 5 V H U m N R D MA .A Y B mm m0 lb A oo wm Nb mm o-.

Patented Aug. 26, 1952 AUTOMATIC CONTROL OF INSPIRATORS- FOR GAS PLANTS- David W. Shaefier, St. Louis, Mo., assignor to Phillips Petroleum Company, a corporation of Delaware Application November 3, 1947, Serial No. 783,661 (01. 48180) 4 Claims.

This invention relates to gas air inspirator systems. In one of its more specific aspects it relates to an electrically operated and fully automatic gas air inspirator system.

One object of my invention is to provide an electrically operated and fully automatic gas air inspirator system. Another object of my invention is to provide an electrically operated and. fully automatic gas air inspirator system which continues tofunction even during periods of electric power failure. Still another object of my invention is to provide an electrically operated inspirator system, which during times of electric power failure, continues in smooth and uninterrupted operation.

Electrically operated inspirator systems are relatively simple to construct and operate and the operation of such systems is very easy to control. However, in case of electric storm when the electric power is interrupted or when power is cut off for any reason whatever, such inspirator systems as now in operation cease to function. I have devised an inspirator system which, as mentioned hereinbefore, is adapted to continue operation even during periods of electric power failure.

The figure illustrates diagrammatically one form of apparatus in which to carry out the improved method of my invention. Referring to *the figure; reference numeral Iwrefers to the gas or liquified gas storage tank which contains gas to be inspirated. Gas from the storage tank I passes by way of a pipe la, a valve 3 and a pipe 2 to a pressure reducing valve 4. From this valve the gas continues passage through line 2, a valve 5, .a line B, a line 9 and a valve In to a second pressure reducing valve I. From this valvethe gas continuespassage on through a line 9, a valve 12, some pipes i6 and 3|", a pipe 28, some valves 29, 2'1 and. From 'pipe 28 the gas passes then through a pipe 34 into a manifold 35 which distributes the gas through some individual lead pipes 34a, 31, 39 and 4| through some valves 36,

38, 4D: and 42,-=resp.ectively, into severalcunits of V the insp'irato'r Zsyste'm: Reference numerals 43, :44; 45" andf46" refer. to some solenoid: operated on-off. valves. From; thesesolenoid.;operated valves gas p'assesinto-the respective inspirators 41,48, 49 :andf50. Fromrthese inspirators the gas air mixture'or mixtures pass through some ducted to my inspirator system through wires, and a. These wires connect with a pressure operated multiple controller switch unit ,65. From this unit 65, some lead wires 60, 62 and 64 are connected directly with the solenoid valves 45, 44 and 43 respectively. Some return wires 59, El and 63 from these three solenoids are connected to a common return wire 68 which in turn is connected'with one side 66a of the power line. To this return wire 68 is also connected a return wire 51 from the solenoid valve 45. The other wire 53 from this solenoid valve 46 is directly connected to the source of power wire 56. The wire 5'! passes through one portion of a signal assembly H and through the electrical switch portion of a pressure operated electrical switch 69. From this pressure operated switch, a pipe it leads to the gas main 56.'

Also from the pressure operated multiple controller switch 65 a pipe 61 leads to the gas main 56. Pipe 1 and valve 6 serve as a bypass: around the pressure reducing valve 4, and pipe I4 and valve 13 serve a similar purpose around the pressure reducing valve II. In a like manner, pipe 32 and valve 33 form a bypass around the valve 21. From pipe 3| a pipe I! leads to a pressure reducing valve I8, the downstream side of which is connected to a pipe 19 which carries a restricting orifice 20. On the downstream side of the orifice 20 a pipe 24 leads to the underside of the motor 26 of a motor regulator valveassembly 25. This assembly consists of the motor 25, a valve 21, which are connected by a valve stem 2 I.

To the downstream end of pipe I9 is connected a valve 23 which is aback pressure regulator type of valve. From this valve pipe 22 leads to the gas main 56.

The pressure reducing valves 4, II and [8 are of the constant pressure outlet type of valve, and in operation valve 4 is intended to reduce the gas from its storage tank pressure to about 50 pounds per square inch Valve H is intended toreduce the pressure from this 50 pounds to about .25 pounds while the valve la is intended to reduce the pressure from 25 pounds to that of an 18inch column of water. i Lowpressures in. such systems, that-is, .pressures of a few ouncesper square inch are frequently measured and expressed in terms of inches of a column of water, for example, the 18 inch water column pressure above mentioned means the pressure exerted by a oolumnof water 18 inches high; if i i The motor re'g ulator valve assembly 251 is of the zero governor throttle type and isvintendedto 3 throttle the flow of gas through valve 21 or to shut olf entirely valve 2? in response to gas pres sure in pipe 24.

The solenoid operated on-off valves 43, 44 and 45 are of a type that when electric current is flowing through the solenoids, the valves are held fully open, and conversely when the electric current is not flowing through these solenoids, the valves automatically close. The solenoid operated on-off valve 45 is like the other solenoid valves excepting it operates in exactly the reverse manner, when the electric current is flowing through wires 5'! and 53 the solenoid holds valve 46 closed and when electricity .ceases to. flow through wires 51 and 53 from any causewhat-- ever, the valve 46 opens.

The pressure operated multiple controllerswitch 65 is standard equipment and may be purchased from instrument supply houses. This pressure switch 65 operates in response to gas pressure in the main 55 and. as pressure in the main 56 decreases; the valve 43 opens, when pressure in 50: decreases'further the, valve 44- also opens andsimilarly uponra still further decrease in main pressure the third valve 45 opens.

1a the. operation of my apparatus, the valves 5; l3 and are normally closed so that gas to be inspir ated" will. he forced to pass through the 1 'ul'ators 4,. H and valve 2:! and accordingly high: pressure gas suchaspropane from the storagetankwill flow through: line [a at tank pres- Su'r'eto the regulator valve 4. Thisvalve reduces the pressure onzthn propane to. a 50 pound discharge pressure. This 50 pound propane then continues. through line 2,.line. 8, line 9 to valve II. On passing through; this valve. the pressure on the; propane is reducedzto a constant outlet'value of about pounds. per. square inch. This 25 pound. propane; then. flows on through. line 9, valve I 2 through. pipes 31 and 28. In normal operation, the motor va ve. 21. is fully open and the propane of 25 pounds pressure or approximately at that: pressure passesion through valve and line. 34; to the manifold 35-. From the manifold 35' the. propane passes through the in- .spirators 41,. 48 and 49 depending uponthe gas requirements of the system. In one casein which aisystemwasdesigned for a maximum demand of 20001 cubic feet per hour output, the inspirator 4:1 was: of: such: size: as to have a capacity of 500 cubic; feet per hour, inspirator had a capacity of 1500 cubic feet per'houninspirator 49 had a capacity-'of2000' cubic-feet per hour. The standby; inspirator 50'had a capacity of 3000 cubic feet pershouri. Thuswith. a normal maximum demand M12000 cubic feet. per hour, inspirators 41 and 48 could carry the load. When demand exceeded 2000 cubic. feet. per hour, then inspirator 49 would turn-chin responset'o apredetermined drop. in gas main: pressure. With this inspirator 49 operationthe': total outputof the three-inspiratorswas 40.00: cubic feet. per hour and this large output would soon raise. the pressure in the gas main to such arr extentthat the controller switch 65 would operate-triclose the solenoid operated valve 45. In like manner, when the valves 43 and 44 were open permitting the production of about -2000icubi"c*feet; of gas per hour and if the load 65 to close off the valve 44 for such a length o'itime until the gasxmain pressure dropped sufrficientlytoopenthe valve 44 again.

times while electric current is available.

' propane from.manifold line 35 through pipe 4|,

through valve 42-; valve 46 and through the inspirator-50. This inspirator 50 may be of a 3000 cubic feet per hour capacity so that it can more than satisfy the normal maximum demand on the system. Discharge from the inspirator 50 flows through-ivalve; 54-, the manifold line. 55 into the gas: main 5.6; Since the valve 45 is of, the fully opened or fully closed type, when it is open pressure in the gas-main usually'builds up quite rapidly if the demand onthe system is less than 3000. cubic feet. per hour. I have devised athrottling' control for use under such condition so that .the pressure in thegas mainwill not continue-to increase to such an extent as to rupture pipes or'otherwise create hazards. The throttling action mentioned is accomplished by the operation of. the zero governor-valve assembly 215. In normal plantoperation if. thev gas. pressure in the main 56 is intended to. be. a maximum of about 6 inches of water column (W. C.) when the pressure. in the. main exceeds; 6 inches, water'column very. slightly. the, back pressure regulator valve 23 operat'esrto. close part-1y. This; partial closing of.valve .23. causesthe pressure, on the downstream side; of orifice 20 in line IE: to increase somewhat and this increase. of" pressure is; transmitted through pipe: 24 to the underside ofv the diaphragm in themotor-ZG and this increase ofpressure on the diaphragm operates tov close partly or throttle. the: valve. '21 In this manner the propane reaching the valve 21: leaves this valve at a pressure less than: 25 pounds per. square inch. And. at. a pressure lower; than 25 pound per square inch less propane. flows through manifold line 35' and through. the. solenoid valve 46 and inspirator. 50. and accordingly pressure in :the gas main. 56' drops. These several apparatus par-ts, that is, control valve 23, the zero governor 25, cooperatively operateito maintain a desired max.- imum gas. main. pressure of about 6 inches W. C. If for some. reason. pressure. inthe gas main decreases below 6 inchesW. C; valve 23'opens some- V spirator, the regulator valve 25 and the pressure regulator valve- 23 are so adjusted that the valve 2T will be. throt'tled tosuch an extent-"thatit will passapropanea at about. l0 pounds per square inch pressure. At this pressure the inspirator 5 0 will add sufiicientair that the mixture discharging from this inspirator will. have a. B. t; u. content of approximately 8.00 per cubic 'foot'.-Of course, the inspirator 50 canjbe set to discharge: the gas air mixture at any desired-B. :t. urcontentn When the three inspirators 4.1, 48q-and 4,9 are operating under 2.5 pounds pressure tqgproduce'approxi mately 800 B. u. gas air mixtures, the inspirator illsh" uld be so adjusted as to proddceagas air mix ur'efof the-same h'eating' value-so that standpaperless-win be the same as 'normal 'opera- At'ti'meswhen the demand on; such' a system i's exceedin ly great, I'have made provisionthat inspirator Silmay be opened to the system to help satisfy "the demand. The apparatus which permits simultaneous use of a large inspirator 59 is aypressure operated electrical switch 69'.- The pres'sureportionpf this switch is connected by pipe 'to "the gas main 56. In operationwhen the inspirators 41, 48 and 49 are making gas and the-pressure in the gas main decreases to a low value as forexample, 4 to 5 inches W. C. this low pressure is transmitted throughpipe 10 to the ressure operated switch 69which causesthe switchtd dp'en'and break the electrical circuit flowing through-Wires Hand 58. When this circuit i'sbroken-the solenoid valve 46 snaps open and-propane at pounds pressure then flows through inspirator and into the gas main 56. Under such conditions pressure in the gasmain soon increases to such an extent that the pressure'operated electric switch 69 operates to close the circuit in wires 51 and 58 and close the solenoid operated valve 46. I

I As mentionedabove, the inspirator 59, in one installation, was adjusted to produce an 800 Bxt. u. gas airmixture at apropane pressure of 10 pounds persquare inch and under this adjustment. when propane flows through this inspirator at 25 pounds per square' inch proportionately more air isdrawn into the gas and the gas air mixture emerging has a lower B. t. u. content. In

one case, atapropane pressure of 25pounds per square-inch, I found that the B. t. u. content of the gas air mixture was 750 per cubic foot. While this B. t. ,u. contentmay be abnormally low, yet it will have only a small effect on the B. t. u. content of the gas air mixturein the main 56, since that issuing from inspirator 59 will be mixed with the mixtures issuing from the other three inspirators. v l I The same condition will exist at times of power failure when the standby inspirator 50 snaps into operation to-replace the inspirators 41, 48"an'd 49. Atthe instant of change when inspirators 41,48 and 49 close and inspirator 50 opens, propane will reach the latter inspirator at 25 pounds per square inch. This high pressure will cause the pressure in the gas main to increase rather quickly above 6 inches of W. C. and this increase in gas main pressure will be transmitted to the regulator valve 23, cause pressure in pipes I9 and 24 to increase and this increase accordingly operates the motor 26 to throttle the valve 21. This last operation takes place quite rapidly so that the large volume of propane at 25 pounds pressure passes through the inspirator 50 for only a very short time and accordingly the low B. t. u. gas air mixture from inspirator 5D is discharged and enters the main 56 only momentarily or for such a period of time until the motor valve .25 throttles to reduce the propane pressure reaching the inspirator 5B. As soon as this propane pressure is cut to 10 pounds per square inch then the normal gas air mixture of 800 B. t. u. will be produced in the inspirator 50.

I have found that the switching from the inspirators 41, 48 and 49 to the standby inspirator 50 is so rapid and noiseless that an operator seldom knows that the change has been made. Of course, the change is made on account of the power failure,'and when a power failure occurs the operator should be warned in some manner;

To furnish a warning under such conditional have shown in the drawing a signal assembly" which isintended to turn on a light or ring' a hell or otherwise warn the operatorthat theelectrlc power has failed and that the standby inspirator 50 is in operation. In case the signal assembly includes an electric light bulb or a bell, a battery should be provided to furnish electricity for this signal. The operation of this assembly is very simple and is such that when the current. fails to flow in wires 51 and 58 for any reason whatever, a relay Ila. operates to cause the battery circuit to ring a bell or light a light. And. when the current starts to flow along wire 51, this *relay Ha then operates to open the signal circuitto shut off the light or stop the ringing of the bell;

. In the operation of the back pressure controller valve 23 and of the restricting orifice 20, the pro pane or other gas which flows through'the. small orifice 20 fiows on throughthe valve23 and into the gas main 56. Since the orifice 2D is very small and since the gas reaches the orifice. at only 18 inches of water. column pressure the amount flowing through the orifice 20 and regu lator 23 into the main 56 is so small that it has little. to no eifect on .the B. t. u. content of the gas in the main. I I l 1 In the illustration given herein I have shown a three inspirator system with-one standby inspirator, but I do not wish to limit my invention to sucha number of inspirators since it will be obvious to those skilled in the art that any number of inspirators of. any desired capacity may be used. For example; if sixinspirators are of the type of inspirators .47, 48 and 49 then the pressure operated multiple controller. switch .65 should have six control Wires such as wires 60, 62 and 64 leading to the six inspirators. In like manner, the number of standby inspirators may be more than one. For exampleit may be desired to use two or three or more smaller inspirators in place of the large one which I have described. i 1

Materials of constructionmay ordinarilybbe selectedfrom those available on the market and suitablefor the purpose at hand. In like mariner,

the solenoid control valves, the pressure'operated 7 multiple controller switch 65 and the zero governor throttle valve assembly 25, the back pressure regulator 23 and the constant pressure outlet valves 4, H and I8, are all standard equipment and may be purchased from manufacturers or dealers.

It will be obvious to those skilled in the art that many variations and alterations may be made in such a system as herein disclosed and yet remain within the intended spirit and scope of my invention. I wish to be limited not by the particular example given but only by the appended claims.

Having disclosed my invention, I claim:

1. In an electrically operated gas-air mixing system which is operable during times of electric power failure as well as during times when electric power is available, the combination of a source of liquefied gas under pressure, afirst inspirator for mixing air with gas, a conduit for passage of gas from said source to said first inspirator, a gas main, a conduit for passage of mixed air and gas from said first inspirator to said gas main, a first electrically operated control valve for controlling the fiow of gas from said source to said first inspirator, said electrically operated control valve adapted to open while electric current flowing to the. electricalecontrol of ;said valve and to'close. whencurrent-is not flowing thereto, a first pressure responsive control meansadaptedto. control saidfirst electricallyoperated control valve in response to gas mainpressure, a second in pirator .for mixing air with; as,,@a-. conduit-forjpassage of; gas from said. source to .said second inspirator, a conduit forrpassageof mixedair and gas-from saidsecond. inspirator to "said gasmain, a second electrically operated control. valve for controlling the-gflow cigas. from said. source to said second inspirator, saidsecondelectrically operated control valve adapted. to: close when electric current flowing to the :electricalcontrol oi said second valve and to. open when currentv is not flowing thereto; a. second... pressure-responsive control means. adapted: to.:contro1. said secondv electrically operatedcontrol valvein response torgas main pressnreandmsaidifirst and second electrically operated control valves. operated by electricity from a commonlsource. 12;; Int an. electrically operatedgas-air mixing system. which is'op'erable'during timesjof electric poweriiailure iaswell' as during times when electric powerxi iavailable, the combination.comprising av source .ofliquefied gas under pressure, a first inspirator means for mixing airwith gas, a gas-main, a' first conduit for passage ofmixedair and gas fromsaidinspirator means to said main, a firstcOnduitmeansfQr passage of gasfrom said source; to said. inspirator means, a pressure reducing means .insaid. conduit means, said pressure. reducing means in said conduit means re.- sponsive. to pressure in said gas main, a first om-off. electrically operated flow control valve in said. conduit means, said first electrically operated flow-control valve adapted to remain open during suchtime as electric current is flowing to the. electrical. control of said flow-control valve and to close when current is not flowing thereto, a first "pressure responsive control means adapted to control said first electrically operated control valve in response to gas main pressure, a second inspirator for mixing air with gas at a greater rate than said first inspirator means, a second conduitfor passage: of air-gas mixture from said second inspiratorto said gas main, a second conu t en e seem s dewe rs reducing. means in. said. first conduit means said second inspirator, asecond electricallyroper ated on-off flow-control valve in said secondzcon v duitmeans said :second electrically operated flow-control valve adapted to remain closed during such time as" electric. current is fiow-ingtothe electrical control of said second. flow-control valve and to openwhen. current. is. not. flowing thereto, .a.-second: pressure responsive control means adapted; to controlzsaid. second. electrically operated on -ofi control valve in response-to..gas main pressure andsaid firstrand second electriecally operatedcontrol valves operated city fromacommonsource,

3. The apparatusof claimz-inwhich said first inspirator means. includes a plurality-of inspirators, said-first 'on.-oif electrically operated flowcontrol: valveincludes a ,pluralityot onx-off elec? trically operated flowcontrol. valves, one eacl'r of said plurality of on-ofi electrically operatedfiowcontrol valves disposed in said conduit meanssto control flow ofgas fromsaidsource to one each of said plurality ofinspirators, and saidplurality of on-oif electrically operated :flow controlva-lves adapted. to close. and to open successively in re:- sponse to successive changes of :pressure in said gas. main, and each of. said plurality of: valves adapted to close'in 'caseof electric power failure, and wherein said secondelectrically operated on-ofi flow control valve is responsivestoipressure in said gas main and is adapted to opezrini case electric poweris cutoff therefrom.

4. The apparatus of claim 3' further characterized by an alarm means. disposedi'operatively with said second electricallyioperated on'vofliinow control. valve to. indicate the opening of this valve. 7

DAVIDW. S'HAEFFER;

REFERENCES CITED The following references are of recordi'inthe file of this patent? UNITED STATES PATENTS' Numberv by electrls

Claims (1)

1. IN AN ELECTRICALLY OPERATED GAS-AIR MIXING SYSTEM WHICH IS OPERABLE DURING TIMES OF ELECTRIC POWER FAILURE AS WELL AS DURING TIMES WHEN ELECTRIC POWER IS AVAILABLE, THE COMBINATION OF A SOURCE OF LIQUEFIED GAS UNDER PRESSURE, A FIRST INSPIRATOR FOR MIXING AIR WITH GAS, A CONDUIT FOR PASSAGE OF GAS FROM SAID SOURCE TO SAID FIRST INSPIRATOR, A GAS MAIN, A CONDUIT FOR PASSAGE OF MIXED AIR AND GAS FROM SAID FIRST INSPIRATOR TO SAID GAS MAIN, A FIRST ELECTRICALLY OPERATED CONTROL VALVE FOR CONTROLLING THE FLOW OF GAS FROM SAID SOURCE TO SAID FIRST INSPIRATOR, SAID ELECTRICALLY OPERATED CONTROL VALVE ADAPTED TO OPEN WHILE ELECTRIC CURRENT IS FLOWING TO THE ELECTRICAL CONTROL OF SAID VALVE AND TO CLOSE WHEN CURRENT IS NOT FLOWING THERETO, A FIRST PRESSURE RESPONSIVE CONTROL MEANS ADAPTED TO CONTROL SAID FIRST ELECTRICALLY OPERATED CONTROL VALVE IN RESPONSE TO GAS

Images