US1280848A - Drifting and relief valve. - Google Patents

Description

H. F. RlPKEN. DRIFTING AND RELIEF VALVE. A'LICATlON FlLD MAR-23|1918 Pufoented' Oct. 8, 1918r mama . exhaust channel on that side.

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HUGO F. RIPXEN, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR OF ONE-HALF TO CHARLES A. MCCULLOCH, 0F MINNEAPOLIS, MINNESOTA.

nmrTINe Ann RELIEF VALVE.

Specification of Letters Fatentf utented @et sa 1918 Application filed March 23, 1918. Serial No. 224,198.

To all whom it may concern.' l

. Be it known that I, HUGO F. RIPKEN, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Drifting and Relief Valves, of which the following is a specification.

My invention relates to improvements in drifting and relief valves for reciprocating steam engines, and especially for those employed in railway locomotives using superheated steam.

The present invention is an improvement to be applied in the drifting valve shown in my pending application for Letters Patent on drifting and relief valves, filed June 1o, 1916, serial No. 108,328.

It will be understood that when the throttle valve of an engine moving under steam pressure, is closed to out oil' the steam supply from the cylinder the engine will drift for some time before it actually comes` to rest. In thus drifting, the piston will continue to reciprocate under the inertia of the locomotive.

When, in an engine the live steam supply entering the cylinders is out off, the pressure behind the advancing piston (during the drifting) is reduced to a degree which tends to or does'create a vacuum at that point. This causes an inrush of air through the usual cylinder cocks and also from the smoke box through the exhaust nozzle and exhaust chamber when'the piston valve in the steam chest has uncovered the port to the In engines having superheating` equipment thecreation of a vacuum behind the piston is very objectionable, the resulting inrush of air, gas and other foreign matter causing combustion and the destruction of the lubrication in the cylinder, thereby resu ting in undue friction and excessive. wearing of parts.

The object of the present invention is to positively controlling the movement of the yalve piston and for controlling the'pressure above the piston, when the throttle is closed.

Mo1e particularly the invention consists in the construction, combination and arrangement of parts hereinafter described and claimed.

In the accompanying drawings forming part of this specification,

Figure l is a vertical, longitudinal section through the middle of the cylinder and steam chest of a reciprocating' engine with my improved valve in elevation, and

Fig. 2 is a vertical section through the middle of. the valve alone.

In the drawings, rL-represents the cylinder 'of a reciprocating engine, B the piston working therein, and C the Steam chest in wliichworks a valve piston D, all of usual type.

The driftingvalve which is the subject of this invention `comprises a cylindrical casing or valve body 2, the interior of which ais opent'o communication with one end `of the interior of the cylinder through the me dium of the threaded mipple at the lower extremity of the valve body, the interior of which leads into a duct 4 extending around a bushing at one end of the steam chest to the cylinder port 5 on that Side of the piston B.

The compressed air or steam in that end of the cylinder will thus pass through the duct l into the lower partof the valve casing, under the valve, hereinafter described. l Y f Leading from the top of the valve casing 2 to the main steam supply pi pe or conduit E and communicating with the interior thereof is an auxiliary steam supply 'pipe fi communicating with the interior in the top of the casing 2, the casing being provided at one side, projecting laterally therefrom,

with a live steam inlet 7, which is open tol communication with the pipe 7 which is f u the point where it joins the lower portion, provide in my prior invention, means lou.

-'a circular fiat seat or Shoulder 9, which seats on a cooperating shoulder 9 in the casing.

The piston may therefore be termed a differential piston as it has a; top and bottom of different diameters and main and auxiliary bottom surface. A plurality of oblong portsY l0 pierce the periphery of the upper portion ot the piston` suitable piston rings to prevent leakage being provided above and of live steam supshoulder 14 in the the valve .piston 8,

below the ports therete.

, A bushing 11 wherein the piston 8 slides,

4thereby forming the annular walled chaminlet 7, the inlet being ber portion 'of the' open to communication with the interior of the supply pipe 7?. This inner wall of the inlet chamber portion is pierced by a circumferential row of ports 13, which are arranged to register with the ports'l when the piston l8 is slid upward against the casing.

Leading downwardly from the annular Vchamber portion of the inlet, in the casing y'wa-ll and opening into the interiorjot the casing at a point above the shoulder 9 (whereon the piston normally rests) through the port guarded aga-inst leakage rings in the piston.

lt will be noted (Fig. 2) that. the Ap orts 10 and 13 are adequately protected by piston lby suitable piston i rings to guard against undue leakage of steam :from the pipe .Opposite the port 15', piercing the wall of lthe casing at a point in the shoulder 9a is a vent 16 which acts as an erhaust and may he open to the atmosphere, or be connected with the exhaust chamberas shown in Fig. 1.

ln operation, when the throttle valve, not shown is closed, the pressure in the conduit immediately thereafter falls or is reduced, while the piston (lf ig. 1) will travel, (while the engine is drifting), to the right, compressing the gases before it, and producing a back pressure in the cylinder, in the port 5, and in the vduct 4. This back pres-sure is communicated to the bottom f causing itr to loe lifted from its seat in the casing and slide upwardlyl until it abuts against the shoulder Qt. When in this position, as hereinbefore stated, the ports and 13 are in perfect register, thereby establishing communicationv between the interior of the pipe 7 and the interior of the casing. i

Live steam from pipe 7 will now pass (as Vindicated by `the arrows Fig. 1) through the inlet into the casing 2 above the valve piston and through the medium of pipe G and con' duit ll enter the steam chestland cylinder, where it will prevent any vacuum forming tendency behind the piston.

lllyhei'einbefore mentioned, prior invention, operated, generally up to this point, as above described, but l have found by experiment that the pressure i thc conduit (when the throttle is closed) which is counteracted only by the back pressure generated in the cylinder and the friction of the parl(- ing rings (on the valve piston) and which, in my prior invention was solely relied upon t0 maintain the valupisto in operating and immediatelyV ralliacent i .15 is a duct the port being position, was not adequate, to prevent a fluctuating movement of the valve piston which lcaused the supply of steam admitted through the inlet 7 to be reduced to` such a degree as to render the pressure in the cylinder ina-dequate for drifting.

To prevent a' fluctuating movement of the valve, I provide the duct 15a having a port cessive conduit pressure on the top of the valve piston, thereby controlling movement of the piston. y

As the valve piston 8 is automatically raised, (by pressure generated in the cylin-v der), it uncovers the port 15 to admit live steam to the annular cavity formed between the seat, 9 and its copcrating shoulder 9 in the casing w(when the valve piston moved) the steam pressure in the cavity serving to regul'atethe pressurewhich causes the downward movement of the piston as will be hereinafter explained.

The vent 16 admit-s air to the cavity to prevent the creation of the vacuum therein (when the valve piston is raised) which would otherwise tend toy oppose-the back pressure generated in the cylinder. It also acts as a restricted, outlet for the inrushing steam, the vent 16 being appreciably smaller than the inlet port' 15, resulting in back pressurein the cavity, whereby the piston is controlled to descend only when there is execs sive steam pressure above it, which occurs when the engine .is drifting very slowly or actually comes to rest.

`When the engine comes to rest the valve piston descends, covering the ports 10 to cut off the live steam supply and then covering the port 15 from which point it will slowly descend, lridingion the air or steam pocketed in the cavity which is now expelled through 11()l the restricted vent, 16 by the descending piston, whereafter the piston valve comes to rest on itsseat.

While I prefer the particular construction shown in the drawings, I wish it understood that. many Variations in the general structure may be made without departing from the general principle underlying my invention.

I claim:

1. In a reciprocating engine, the combination with the cylinder and steam chest, of a drifting valve comprising an outer ycasing open to communication with the cylinder at 'one end and communicating with the steam 125 chest at the o'her end, an annular-'ported steam inlet chamber in the casmg to admit live steam, a ported shdable valve piston in thrl casing having a shoulder and adapted to register with its ports, the ports in said an- Leens-1s nuler chamber but nori'nallyl covering the latter and actuatable by the pressure in the cylinder when the engine is drifting and the Vic main steam supply is cut oli', and a duct the casing open to communication with said annular chamber at one end and opening at its other end against the sliding face of the poited valve piston above said shoulder and rendered operative, when the valve piston is actuated to uncover the ports in said annular chamber and said opening of said duct to admit live steam into contact with a part of the piston below7 said shoulder to'control live steam inlet to admit live steam, a ported differential valve piston in the casing norinally covering said live steamvinlet to liold the interior of thecasing abovethe piston closed to communication With the steam chesu and actuatable by pressure' in the cylinv der when the engine is drifting and the main steam supply is cut ofi', and having a main and auxiliary pressure receiving'. bottom s ur-' faceand a duct in the casing open to com-' munication with said live steam inlet at one tion with said auxiliary pressure receiving bottom surface at the otherend, but opened` to communicate therewith when said differentialv valve piston is actuated for the purpose set forth.

- 3. ln a reciprocating engine, the combination with the cylinder and steam chest, of a drifting valve open to communication with the cylinder at one end and communicating with the steam chest at the vother end, said drifting valve comprising an outer casing having a differential bore and an annularv ported live-steam inlet to admit live steam,

a. valve piston in the bore of the casing actuf atable by pressure in the cylinder when the' engine is `driftiii and the main steam supply is cut off and normally holding the interior of the casing above the piston closed to communication With said annular ported live steamV inlet anda duct open to communication with the annular live steam inlet, and having a port adjacent the point of differentiation in said bore and normally covered by the valve piston and rendered effective when the valve piston is actuated to admit live steam into the casing above the piston and said port is uncovered to admit live steam to completely surrounda part of Jsaid valve` piston to exert ,an 'upward pressure thereo 4. In 'a reciprocating engine, the combina-- tion with the cylinder and steam chest,l 'of a drifting valve, comprising ,a valve casing open to communication with the cylinder at one end and the steam" chest at the other endl, said valve casing having a live steam inlet and an internal shoulder, a piston'having a peripheral seat adapted to engage said shoulder and normally in engagement therewith 1 covering said live steam inlet, said piston being actuatable to disengage said' shoulder and uncover said live steam inlet by the pressure in the cylinder when the 'engine is drifting and the main steam supply is cut off, a duct in the casing open to communication with said live steam inlet and the interior of thevalve casing adjacent and above said shoulder,- and a vent piercing said shoulder and opening against said peripheral seat of the piston when the latter is in engagement 4with said shoulder whereby when the piston. is Vactuated to uncover said live steam 4inletto admit live steam into' the interior of the valve casing above the piston steam admitted through the duct tothe underside of said peripheral seat to exert pressure thereon may escape lsaidvent and duct differentiating in size for the-purpose set forth. end and closed by the piston to communica`.`

5. Ina reciprocating engine, 'the combinaftion with the cylinder and steam chest, of a Vand the steam chest at the other end, a movable ported device fitted slidably in the casing and dividing the interior thereof-` to pref vent conununicationdbetween said ends and actuatable by -thepressure in the cylinder when the engine is drifting and the main steam supply is cut olf, a ported live steam inlet/in the casing in the path of said ported movable device and ther with when thelatter is moved, a duct open to communication at one end with said adapted to register live steam inlet, and means in the casing and said movable device cooperating when the latter is moved to further divide the in'- terior of the casing and to uncover the other end of .said duct into communication with the interior of the casing for the purpose set forth. l

In testimony whereof I aflix my signature in presence of two Witnesses.

HUGO F. RIPKEN, Witnesses: i

GEORGE VOELKER, FLORENCE WINKLER;

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