US1662918A - Unloading system - Google Patents

Description

Match 20, 1928. 1,662,918

. H. v. HAIGHT UNLOADING SYSTEM l Filed June 2e, 1925 4 sheets-she'i 1 INVENTOR. @y' nizw IIR-iat Nimh 2o, 192s. 1,662,918

H. V. HAIGHT UNLOADING SYSTEM Filed June 26, 1925 4 Sheet-Sheet 2 Hw I' IN V EN TOR.

H. V. HAIGHT UNLOADING SYSTEM Filed June 26, 1925' 4 Sheets-Sheet 3 March 20, 1928. 1,662,918

March 20 1928.

INVENToR.

4 Sheets-Sheet 4 A J 4 Y HIS AIjToR EY H. v..|HA|GH-r UNLOADING SYSTEM Filed June 2e, 19,25y

Patented Mar. 20, 1928.

UNITED STATES PATENT OF-F'ICE.

HARRY lv. HAIGHT, 0E sHERRRooKE, QUEBEC, CANADA, AssrGNoR To INGERsoLL- RAND COMPANY, 0E JERSEY CITY, NEW JERSEY, A CORPORATION oF NEW JERSEY.

UNLoADING hsr'srint.

Application mea June 26, 19:25. serial No. '3936s.

This invention relates tounloading systems and presents features 'of general appllcation especially adva'fitageo1'1s whenapphed to a system in which it is desired to maintain the 'power consumption within a predetermined maximum limit. Insuoh a system there may be two or more devices consuming power, one of which is adapted to be unloaded to reduce 'the -power consumption while the other is operating or 'at leastdurmg its accelerating Ip'eri'o'd so that `the total power consumed shall not exceed a given `amo unt.

An inst-'ance of a 'systemy to Which'this in-f vention is applicable is "found in most inine installations 1n which therels provided a main air compressor for 'furnishing air fory operatingl n'liscellaneous machines, suoli 'as drills, 'and a hoist for raisingandlowering material from the mineV shaft. Generally, the hoist and con'ipresso'r are both electrically Idriven and the power purchased at a rutebase'd upon thefmaximum demand. It

is therefore desirable 'that peak-loads bev avoided. At the start-ing up ofthe hoist and during its acceleration period, a heavy draft. of current occurs for a short tlme'so that it is desirable that the current con-4 sumption of other'apparat-uses such as the compressor be dismissed at that time.

One object 'of this invention is to enable the peak-load due tosudden power demands ot' short duration to be done away with. This is accomplished by providing apparatus which unloads the compressor or one of the power consuming devices, while another, such as a hoist, is 'drawing' an abnormally large amount of current, as for instance, during its accelerating period. Another object of the invention is to control the yvarious power consuming devices pneumatically such as by means of :compressed air, this being available in installations including a compressor. It will be understood that this systen'i may be employed in steam driven plants. One advantage of this hoist is that it will not be necessary to provide a power generating Vplant of a size sulicient to supply steam :for peak-loads in such a case.

Other objects and advantages of the -invention will be in part obvious and in part pointed out hereinafter. n

In the drawing forming part of the speciication and in which similar reference 'characters refer to similar parts,

Figure 1 is a "diagrammatic representa! tion of a'system'including an yair compres-v sor and va vhoist provided withpower unloading means-for the compressor automatically operable wlienthehoist is being Started and during its acceleration period,

Figure 2 represents a power consumption f curve for the air compressor motor, i

Figure 13 represents a power consumption curve of the hoist motor 'during its accele'ration period. n

4 representsthe combined power consumptionfcrves of the air compressor motor and the hoist motor during the accelerating period of the latter, y

,l Figure 5 is a detail view partly in section of I an electrically y controlled pilot and relay valve for nlo'z'tding the air compressor,

I `i`gu`re` Gis a detail ofthe pneumatic` relay for operating lthe unloading mechanism ofthe air compressor, l

Figure Tis a-view of a mechanically operated, vand Figure. 8 is a detail View of the mechanically 'operated pneumatic"l relay `shown in Iigure 7 in another of its operating positions. y y

Referri"ngA to thek drawings and more espneumatic relay `pecilly ,to Figure l, V`the compressor includes inder H and :piston (not shown)v therewithin v exposed to air supplied from the receiver G mieu-gh a pipe J. The. regalata isSubs-tan-- tially like that disclosed in Patent No. 1,099,457 of aan@ 9, 1914, granted to F. v.y D. Longace andis proyi'd'ed with a pilot valve chest lK, having a. plurality of air lines L, O, P and Q into which a regulator 'valve (not shown) within Ythe valve vChest K is arranged to control the flow of compressed air Y or other suitable, vmotive fiuidfor lselectively` operating unloadingpvalves R, S, T and ,U for the cylinder Band unloading valves V, W, X and Y for the compressor cylinder `A substantially as lshown in Prellwitz Patent No. 1,027,757 of May 28, 1912. The`regula` tor valve within the valve chest K is arranged to successively supply compressed air.

to the pipes L, 0,713 and Q, for successively operating pairs of unloading valves. For instance, at the iirst stage of'unloading the pilot valve releases compressed air in the pipe L whichleads to the unloading valves R and X1 whereupon suitable clearance chambers (not shown) in the cylinders B and A respectively are opened at oppositeV ends of the cylinders B and A respectively, causing y one quarter unloading of the, compressor.

Zie

*l Preferably the unloading oi the cylinders A and B is equal and opposite in the cylinders A and B so` as to balancethe load on the mtor C, u The pipes L, O, P and Q may be successively'connected sov as to operate succesf sive un o` be a hoist motor b arranged to operate a hoist drum dthrough gearing of any suitable description.=` The hoist motor b` is adapted to be controlled by a starting rheostat e which may be hand controlled.-

The starting rheostat is `provided with a rotating shaft f which, as shown in Figure 5, also supports a cam g to be rotatedwith the shaft f. As the shaft f isrotated ina clockwise direction to operate the rheostat e for starting the motor b the cam g is adapted to strike against a block h pivotedon a lever ,71: cooperating with an arm on the switch blade p causing the switch blade p to break contact with a switch contact g.

The lever [cis pivoted at one end `on a pin amounted on a base s and is provided with a' spring t supported on a boss u on the base s tending to pressthe lever k toward the left normally'out of engagement of the arm j on the switch blade pl The blockh is pivoted on pin e` and bears against afpin w mounted on thelever 7c 'forwardly and below the block 7L so `as to prevent downward movement of the block 7i. when pressed by the cam g-"romabove.` A spring m normally tends to' hold the block 7i against the pin lw. Due

to the pivoted arrangement ofthe block h,

on the lever 7a the cam g upon rotating in a counter clockwise direction will strike the block 7i moving it upwardly without operat ing the lever lc.

The Switch tud@ p und rheswach Contact giare adapted normally to complete a cir# cuit"`through` the conductor yleading from one of `the,electric conductors D to a binding post e, a spring 2` the switch `blade p, a switch contact g, a binding post 3, a conduc tor 1, an electromagnet 5 and a conductor 6 to theother side of the line D; c

The electromagnet 5 forms part of an electropneumatic relay having an armature pivoted intermediate its ends on a pin 8 and connected at its lower end by a link 9 to a lever 10 having a pivot 10. The base 11 of the electropneumatic relay supports a valve chamber 12 having a bore 13`within whichv a valve stem 14 is adapted to reciprocate. i The end ofthe valve stem 14 extends from the valve 'chamber 12 into the path of the lever 10 so that when the armature 7 is released upon deenergization ot' the electromagnetf a spring 15 attached to the lower end of the armature is adapted to retract the lower end of the armature causing the lever l0 to press against the end of the valve stem 14 pressing it inwardly.` A valve 16 is mount`-` ed onf the valve stem 14 being separated thereitromby a. reduced neck 17' permitting thepassage ot air` into the bore 13 of the valve chamber and thence into a transversely bored Ypassage 18 arranged to be connected by means ol a pipe connection 19 with a pipe 20. The valve 16 is provided with a tapered seat 21 and is arranged to open and close communication between a larfrer bore 22 in the valve chamber 12 and tllepassage 18 leading from the bore 13. The larger bore 22 is provided with a screw threaded plug 23 having a passage 24: leading to a pipe threaded aperture 251or connection with an air supply pipe 26. As shown in Figure 1 `the pipe 26 is supplied with compressed air by a supply pipe 27 Connected with the receiver Gf l Upon energization ofthe electromagnet the armature 6 draws the lever 10 out of the path ol the valve stem 111 upon the air pressure supplied to the interior of the valve chamber 12 seats the valve lshutting oit the supply of compressed air to the pipe 20. Upon deenergization of the electromaguet 5 the armature 7 drops back by tension o'l' the spring 15 and the lever 1() presses against the valve stem 14 unseating the valve 16 and permitting compressed air t0` flow Yfrom the interior of the valve chamber 12 past the valve 16 into the pipe 20.

comprises a body portion 28 having a cylindrical bore 29` to lit closely a plunger 3l) upon which ismounted a 'Hat valve31 se.'-

cured to a boltlike extension 32 of the plunger by means 'of a nut 33 and washer The pipe 20 connects with a pilot valve shown in detail in Figure 6. The pilot valve withdrawn-from the body portion 28. Compressed air is supplied to the pipe20 from the electromagnetic relay into the recess 36 and air pressure forces the plunger down causing the flat valve 31 to seat on a valve seat 38 closing communication from a chamber 39 within the body portion 28 to a small longitudinal bore 40. Upon closure ofthe valve 16 of the electropneumatic relay. the air contained in the pipe 2O and the recess 36 is permitted to leakl out through a bleeder hole 41 in the body portion 28. v v

Upon depression of the plunger 30 the bolt like extension 32 is arranged to engage the end 42 ot a second plunger 43 in alignment with the plunger 30 provided with a valve 44 attached to the plunger 43 by means oit a nut 45 and washery 46.V The plunger 43 is arranged to reciprocate in a bore or guide 47 in a plug 48 closing the lower end of the body portion 28. The valve 44 is adapted to close communication between a lower chamber 49 in the bodyportion 28 and the longitudinal bore 40. The chamber 49 is conf; stantly supplied with compressed air from the pipe 27 through a pipe 50 connected with the chamber '49 at thethreaded aperture 51. The upper chamber 39 isprovided with an atmospheric escape port 52 which permits compressed air to exhaust from the longitudinal bore-40. The valve 44 is prevented from opening and closing too suddenly a dash pot formed by the borev 47 and the plunger 43 there being a bleeder port 53 leading from'the lower chamber 49 to the bore 47 below the plunger 43.

One of the functions of the pilot valve is to supply and exhaust compressed air to and from a cylinder 54 (Figure l) provided with a piston 55 connected by means of a connecting rod 56 with thearm 57 of the regulator. To this end there is provided a pipe line 58 connected at the pipe threaded aperture 59 with a p assage 60 leading to the longitudinal bore of the body portion 28 of the pilot valve. Compressed air admitted into the cylinder 54 causes the piston to rise lifting the arm 57 and operating the pilot valve within the valve chest K to unload the compressors A and B in the man- Y ner above described.

'Upon operation of the rheostat e to trip the switch blade p the. electromagnetl 5, being deenergize'd, permits the valve'16 to open, supplying compressed air to the recess 36 of the lpilot valve,- depressing the plunger 30 as shown in Figure 5, causing the valve 31 to close communication to atmosphere through the port 52 from the pipe line 58, and unseating the valve 44 to permit compressed air to flow from the pipe 50 through the longitudinalbore 40 and the pipe line 58 to the cylinder 54.. Thereupon the regulator arm 57 rises, causlng the regulator valve within the valve chest K to operate the unloader valves R, S, T, U, V, W, X and Y, unloading by'diminishing current consumed by the `compressor `motor C. The unloading ofthe.

compressor motor C is simultaneous with the maximum consumption of power by the hoist motor b since, as is well known, an electric motor upon draws a. much'greater current than at greaterspeeds. i

- yUpon rotation'of the shaft f beyond the lstarting position of the,v rheostat e the -cam g disengages the block 7L onlthe lever c permitting the switch blade p again to contact with the switch contact g vdeenergizingithe electroi'i'iagnet 5- and closing. the valve .16,`

wherebysupply oit compressed air-to therecess36 is cut ofi. The compressed air remaining in the recess 36 is permitted toescape-.through'the bleeder 41 -to atmosphere. The `pressure on both sides of the plunger 30 under this condition is atmospheric-and pressure within the longitudinal bore ,40.V

with the regulator arm57 and the com-' pressed air in. the pipe line 58 leak back through the passage 60 and the bore 40 past the valve 31 to atmosphere through the port` 52. This permits the lregulator arm 57,to lower by gravity and correspondingly the regulator valve within the valve chest K rcloads the compressor cylinders A and B.

Figure 2 represents approximately the power consumption curve. of the compressor motor C starting-at a time represented by the point 6l with compressork cylinders A and B unloaded and continuing so to a time represented at the point 62 at which the` reloading' of the compressor starts. 63 represents the time of complete loading. :trom which the curve continues as a straight line, the current consumption-being substantially constant at full compressork loading.

Figure 3 represents a typical power! curve of a motor such as the hoist motor b. The

the compressor and therestarting under load orsl powerv increases trom'zero toa maximum as Y represented at the portion 64 of the curve f as soon as the rheostat is operated. The

rate of current consumption drops olf slightly, as is indicated in the sloping portion 65 as the motor accelerates and then drops down suddenly as indicated in the steeper sloped portion 66 thereafter dropping of more gradually, as represented by the gently sloping portion 67, as the motor speeds up.

The combined power consumption of the two' power consuming devices, the compressor motor C and the hoist motor Z2 is represented i with a to slide in a "lis,

'i in Figure 5.

. 7 0 provided and spring pressed against the pilot valve is provided 82 faced with suitable seat material 83 co- 'operating in Figure 4 the `curve shownin Figure 3 being `superposed on u the curve shown in Figure 2. The vdotted portion 68represents the` peak eliminated by unloading the compressor motor C and the peak now is represented by the ordinate at the point 69. The charge for power consumed by the combined plant is7based upon the peak-load represented at 69 rather than the greater peakload represented at 68.

In Figures 7 and 8 there is shown a modified form ofV pilot valve adapted to be actuated mechanically instead or' through the medium of the electropneumatic relay shown This pilot relay is shown arranged to be actuated in combination with a rheostat in which the moving element instead of beinga revolving shaft as shown at f in Figure 5 is a reciprocating member with a cam surface 71 for actuating a lever 72 pivoted` at a pin 7 8 on a base 7 4. The Vlever 72 is provided with a pivoted block 75 similar in function to the block L pivoted on -ya pin 7 6 mounted on the lever 72 p a pin 77 on the lever 72 by means ot' the spring 78. The spring 78 and the block 75 are held on the pin 7 6V by means of a washer 79 held in place by a cotter pin 80. The body portion 81 of with a fiat valve with the valve seat 84 between a chamber 85 connected by means of the pipe and a smaller bore 86 leading to a central chamber 87 The valve stem 88 which pro jects, through the end of the main body 81 to be engaged by the lever 72 is arranged y bushing 89 fitted in a bore 9() of the body portion 81. Between the valve 82 andthe end sliding in the bushing 89 the valve stem 88 is reduced in diameter as at 91 to permit free passage of air in the bore 86 and forms a. shoulder 92 cooperating with a bore 93 between the central chamber 87 and an exhaust chamber 94. A vent 95 to atmosphere is provided in the wall of the body portion 81 leading from the exhaust chamber 94. The pipe line 58 in this embodiment is adapted to be connected at a threaded aperture 96 with the central chamber 87. With the valve in the position as shown in Figure 7 the pipe line 58 is connected through the central chamber 87 and the pipe constant source ot compressed air 92 cutting oil the atmospheric escape from the port 95, and simultaneously the valve 82 is lifted from its seat 84 permitting compressed air to pass from the chamber 85 into the central chamber 87 and thence into line .58 to actuate the piston whereupon the regulator acts as before described to operate the unloading valves R, S, T, U, V, W, X and Y to unload the compresser. a n

I claim:

1.111 an inter-control system, the com-4 bination of two power driven devices and means for decreasingthe power consumption of one of said devices whilethe other said device is being started in operation including a pneumatic unloader' `for the irst Said device and a valve associated with, the second said device ada )ted to supply pressure fluid tol said unloader during the acceleration period vof said second device and adapted to exhaust the pressure fluid rom the unloader' thereafter to reload the first saidV device. l i

2. In an inter-control system, the combi nation of two power driven devices and pneumatic means for decreasing the power consumption of one of said devices while the othersaid device isbeing started in operation including a pneumatic unloader for the first said device, a pilot valve adapted to supply pressure {iuid to said unloader and to exhaust the pressure fluid therefrom, and an electro-pneumatic relay for controlling said pilotu valve automatically operable during the acceleration period of the second said device.

3. In an inter-control system, the combination of two power driven devices, a starting means for'one of said devices, and an automatic pneumatic means associated with said starting device for decreasing the power consumption of one of said devices in anticipation of and only during the acceleration period of the other said device.

In testimony whereof I. have signed this specification` HARRY V. HAIGHT.

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