US2124390A - Vacuum pump apparatus - Google Patents

Description

y 3- F. H. ANDERSON I VACUUM PUMP APPARATUS Filed May 7, 19:55

Inventor:

r UJ v p m -em PUMP APPARATUS u l 1 Frederick-1H."Anderson, Schenectady, N. Yr,f assignor to General Electric-Company, a corpora-t tion of New York ci I Application May 7, 1935, SefiaPNoLfZDJSS' u e n 1 4 Claims. (01. fast-222') s A v I Myinventio'n relates tot vacuum pump apparelon .enbugh -to clear the pump chamber and n l jtus, particularly t'ojroughing pump apparatus pump suctionpipe of all oilor foreign gases. At 2 operating inconnectionf with ahigh vacuum the-termination of this predetermined time ina mercury condensation "pump for' evacuating terval the valve control means operated to close 5 mercury arc rectiflers or like devices of the metal the relief valve, thereby cutting off theconnec- 5 "tank type; andfit'sgeneral objectis to provide a tion of the pump suction pipeto atmosphere and} t yacuum pump apparatus of this character which simultaneously'; to open the intake valve thereby is of *simplifledanddurable construction and of to connect the pump suction pipe to the exhaust v increased eflicie'ncy'and reliability i'n operation. pipeline of the rectifier fornormalevacuationof A particular object. of the invention is to prothe rectifier tank. I 10 a vide, for the -vacuum pump apparatus, a valve My invention will be better understood from the i means and automatically operated control means following descriptionwhen consideredin connectherefor'so' arranged that high starting 1 torque tion" with the accompanying drawing and its; t usually required in operation of the vacuum pump, scope will be pointed out in th'e appended claims; "ldand difficultlesgdue tofcreepa'ge of oil from the I Referring f to" the drawing; the" single? figure pump intocoritactwith valve members'ordue to thereof is a semi-diagrammatic cross; sectional l jcreepage f oilinto the vacuum chamber of the "view of a vacujum pumpjmechanism 'fori'an iron rectifier or likeldevice; are obviated. tarikr'ectifir or thelike, inflwhich'my invention i' [The 'pump'apparatus'inwhich my present inhas been embodied. t gdyen'tion has been embodied preferably includes an In the fi u e, the'lnumeral'l designates a" verelectrically drivenfpump mechanism which is estically mounted rotary xhaust pumpdriven by" 'sentially similar to pump mechanismsheretofore an electric motor 2. The pump and"motor' are; utilized as foompressors' forrefrigerator. apparaenclosed in a casing 3 normally filled witli oil to "'tus. This pump" mechanism is preferably versuch a heightjtha't the'pump is totallysubmerged 5 ticallymountedgth rotary pump itselfbeing subin the oil bath to prevent'air or othergas'es from s merged in an oil bath, in asubstantially sealed ente'ringthe pump andto seal the pump. Excontairier and being" driven by an electric motor haust gas'es'l from the rectifier enter the pump ;mounted in the container'and aboveltherotary through a pumpjsuction pipe 4 and afteripasspump. y [s 'ingthrough' the pump and pump exhaust "valve 1 In accordancevwithmy inventionhin the.suc'-. .(not1fshown) into the casing 3 escape to atmose 30 tion pipe leadingfroina point on the pump below phere through an air port 5. 1 f I 1' *thefoilf level' to the exhaust pipeline of the The 'motor is supplied with current from' a" R g rectifier is, mounted a combined intake valve ap' suitable current source; such as a "single phase paratus and relief'valyieapparatus, the combined alternating current source, for example, con- 7 n aipparatusbeing so arrangedand controlled that heated to supply lines 6, the current being conwhen the pump is brought to a stop, the intake trolled for starting and running through suitable valve is closed and;siinultaneouslygthe rcliefkvalve motor t control means indicated by the rectangle isopened to admit airnlat atmosphericpressure I, the control means 'I being connect'e d'to the into the suctionxpipeofthepurnp, h v motor by; leads 8 insulated from the'eover 9 Thje i'elief valve remains open Whilethe pump-{by bushings'lfl. In order to start and stop the 40 'standls idle,'therebydestroyingthevacuum in the pump manually a switch means indicatedbyft he pump and pump suction pipe'and' preventing all numeral II is providedin thesiipplylinesto the possibility'of creeping ofoil or'oilvapor into conmptor. t n v v I v v i tact with the intake valve and into the vacuum To control the connection of the pump lt ofthe l 4 chamber of the rectifier. Upon-restarting of the exhaust line llwhich is connected to-the'lvacuum 45. pump the intakeyalve is held closed and'the chamber (not shown") "of a devicesuch as an iron 7 .7 relief valye is heldopenfor apredetermined time. tank rectifier, and to control the admission of 1 i inter-val to admit-Lair as above described to the airata'tmospheric pressure to the pump, a'con,' j pum'p'and pjump'suction pipe." This time interval trol'valve apparatus designated generally by the Y a c L 'isisuflieient'to permit the pump to come up to 1 numeral 'l3;-is' connectedbetween the pump -sue 50 1"normalwspeedi'unloaded; thereby eliminating the tion pipe Mand the exhaust line 12. The valve high star-tingtorque encounteredwhenthe pump, apparatus in the present embodiment'of thein-i is required to start against vacuum. The time vention is preferably constituted by a unitary 215- a interval is extended'afterthe pump comes up' to sembly mounted on the cover 9 of the pump cast- I 1 t 5 speed, fo'r'such 'a period that the" pump runsidle ing '3 and comprising a main valvemeans l'l for member 2|.

exhaust line I2, and a second valve means I5 to control the admission of air at atmospheric pressure to the pump.

The main valve means I4 includes the upper open end of pump suction pipe 4 and a valve disc I6 of rubber or other suitable material mounted in a valve foot I1 which is connected to the lower end of a valve stem I8.

The valve foot I1 is welded or otherwise fas-' tened in vacuum-tight relation to the lower end of a bellows or sylphon valve member I9 which is provided to give flexibility to the movement of the valve stem I8 and to seal off the valve means I4 from atmospheric pressure. The bellows I9, valve foot I1 with its rubber disc I6, the upper end of pump suction pipe 4, and the lower portion of valve stem I8 are enclosed within a vacuum-tight casing 20 having a cover member 2|, the upper end of bellows or sylphon member I9 being connected in vacuum-tight relation to cover A sleeve 22 for guiding the stern I8 projects downwardly from cover 2|.

The second valve means, l5, includes a valve seat member 23 slidably mounted within a valveseat casing 24 and having in its lower face a:

valve disc 25 of rubber or other suitable material, and further includes the upper end or tip 26 of .the valve stem I3, this upper portion of the stem being adapted to slide freely in the lower portion of valve seat casing 24, into and out of contact with disc 25. The valve seat 23, together with its rubber disc 25, is biased downwardly toward the valve tip 26, by a spring 21 mounted in valve seat casing 24. Downward motion of the slidable seat 23 is limited by suitable stop means such as an offset 28 in valve seat casing 24, and upward motion of seat 23 and its disc 25 is also limited by a stop means, such as a downwardly extending portion 29 of aplug 30 which retains spring 21 within valve seat casing 24.

To mount the valve seat 23 and its disc 25 of the valve means I5 in proper alignment with stem I8 and to provide a support for means to actuate the valve mechanism, a supporting and mounting member 3| is provided preferably constituted by a casing member so arranged that the interior of the casingisat atmospheric pressure. The support or casing 3 is preferably mounted on the cover 2| of the vacuum-tight valve casing 20.

To admit air at atmospheric pressure through the upper valve means I5 into the pump suction pipe 4 and the pump I, a hole 32 is provided in valve stem I8 extending longitudinally therethrough and registering with a hole 33 provided in valve foot I1 and rubber disc I6 of the lower or intake valve means i4.

To operate the valve mechanisms I4 and I5 an electrical actuating means is preferably provided which inthe present embodiment of the invention comprises a solenoid 34 having a plunger 35 which is connected as by suitable link and lever mechanism, comprising, for example, two links 36 and two levers 31, to valve stem I8, thelevers 31 being pivoted on thesupporting and mounting member 3|. The solenoid 34 is connected by leads 38 to the current supply line 6 through a switch means designated by the numeral 39. Inv

through a thermostatic switch 43 having a heater element 44 to close contacts 45 in one of the solenoid leads 38 and simultaneously to shortcircuit the heater 44 through contacts 46.

In operation of the apparatus above described, 7

upper side of valve foot I1, and relief valve I5 is open permitting air at atmospheric pressure to enter the upper end or tipv 26 of valve stem I8 and to flow through longitudinal hole 32 of stem I8 and hole 33 of valve foot I1 and valve disc I6 into the pump suction pipe 4 and thence into" pump I. After a predetermined period of time, for example 30 seconds, the thermostatic element of switch 43 operates to short-circuit itself, thereby to supply sufficient current'to actuating coil 4| of relay to close the contacts 45. The period of idle running of the motorv is sufficient to permit the clearing of all oil or foreigngases out of the pump before normal operation begins.

When contacts are closed by the relay coil 4| at the end of the time interval determined by thermostatic switch 43, current, is supplied to solenoid 34 through leads 38; the plunger 35 is then drawn up thereby lifting the valve stem I8 by an amount sufficient to open intake valve I4 by the lifting of rubber disc I6 away from the end of pipe I4, and simultaneously to close relief valve I5 by the forcing of tip 26 of valve stem I8 into contact with rubber disc 25. The upward'motion of valve stem I8 is preferably such that valve seat 23, carrying disc25, is forced upward against the pressure of spring 21 into contact with stop 29, the end of valve stem I8 then preferably continuing its upward motion for a short distance to dig slightly into the rubber disc 25 to insure a vacuum-tight joint between the disc 25 and the tip v 26 of the valve stem.

' of valve stem I8, the relief valve is caused to close and the 'intake valve I4 is caused to open, the

pump. is now sealed from atmosphere and is connected to exhaust line I2 for normal operation in exhausting the evacuated chamber of the rectifier or other device to which exhaust line I2 is connected.

When the pump mechanism is .stopped, as by the manual opening of switch II, solenoid 34 is deenergizedplunger 35 drops to its lower position illustrated in the drawing, and valve stem I 8' moves downwardly thereby reclosing intake valve I4 and reopening relief valve I5, the valve seat 23 which carries rubber disc 25 being moved down, in contact with the upper end of the valve stem, by the pressure of spring 21 until the valve seat 23 rests against the stop 28. When the pump is thus stopped and theintake valve I4 is caused to close, air at atmospheric pressure is immediately admitted to the pump suction pipe 4 and pump I through valve I5 as hereinbefore described. Therefore the vacuum existing in these parts of theapparatus is. destroyed and creepage of oil from casing 3 or from the pump into contact with rubber disc I6 of the intake valve I4, or creepage of this oil past the valve I4 into connected to'atmosphereriollow by the closing 1 oil of the valvebetwee and the opening or the;

' a I particiflarembodiment- 1 p I I us It is to be understood fieifclrthuttl'ijefine ventlon ;is susceptible cv yai'ious changesiand modifications and thkitlb thejappendedclaim's I .intend to coverany gsuch; b lflcations as iaii aiothinkthe truef'spirit and acopefiiof ,my invenn r u m v i a in closed position and to exclude air to said pump,

the exhaust the n and {thence to thefevacuated chamber oi the rectifier DriOtheId2Y10e; is eflectuallyprevented.

' Upon furtherstarting pump the above described cycle of operations, including the period of idlerunning of. themotor- 1 v urpose's not; illustra My invention-has? between an exhaust line'and an exhaust pump, said 'valve' apparatus. including a hollow valve stem. valve means at one extremity of said stem'adapted. to open and to close the path from said exhaust line to said pump, and a second valve means at theiothe'r extremity of u said stem operable simultaneously with said first-named valve means toIadmit air through.- saidste'm to said pump from outside said ex-j' 'haust line whensaid tirst nameduvalve means is from outside said exhaust line when said firstnamed valve means isin open position.

2. A control valve apparatus adapted to be interposed ,,between an exhaust lineand an exhaust pump, said valve apparatus including a hollow valve stem, a valve casing: ands. valve supporting member, the interior of said valve casing beingxat 'thepres'sure oi said line, the interior of the valve supporting member bein 'at atmospheric pressure, .a valve means in said valve casing at one extremityhoi" said stem'to control the conncction'ol-said pump to said exhaust line, a valve means at the other extremity of said-stem in said valvesupporting member to d. pping 1 of the I a t I ciaim,as:,ne' anddesire to secm'ty v1 vni iettersrPatent in the United States is:

1 lm-A control valve apparatus-adapted to be 7 control the admission of air at atmospheric presi sure to said'pump through said hollow stem andl means to operate said two valve'means simultaneously.

3..A unitary control valve apparatus adapted to be'interposed between an exhaust line and a vacuum pump; said valve apparatus comprise ingr tj jvalve stem having a'longitudinal aperture:- herethrough, an intake valve between the pump- -anditheexhaust line including a valve disc G021, fn'cte'd tome and of said valve stem and having an aperture therethrougli registering-withsaid aperture of said stem, a relief valve open to atmosphere and comprising the other end of saidj stemand' a valve disc adapted to close said aperture of said stem, and means to move said valve stem'longitudinally toactuate said-intake and 1 relief valves, whereby said control valvelappa-y ratus is operable, to connect the pump to the exhaust line and simultaneously to disconnect the pump fromatmcsphere and operable there- 1 after to disconnect the pump frornvthe exhaust line and simultaneously to connect the'purnp'to atmosphere. H I 5 e g 4. A control valve apparatus adapted to be interposed between an exhaust line and a vaca *"uum pump, said '7 valve apparatus comprising a valve stem, an intake valve between the pump 1 and the exhaust line including a valve disc memj ber connected to anend of said stem, said-stem and 'saiddisc member being apertured to per ,mit'the passage of air therethrough, a resilient vacuum-tight support connected to said disc member and surrounding said, end oi said stem.

a vacuum-tight casing surrounding said resil-- ient support, said disc member, and said end ot'said stem, said casing being connected to saidexhaust line and to said pump, a relief valve, a relief valve supporting member, said relief valve comprising the tip-oi the other endof said stemand a valve disc 'slidably mounted take valve and simultaneously to close said re-- lief valve. a

in said relief valve supporting member, and.

means to move said valve stem to open said -in-

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