US1412833A - Coling of pistons and piston rods - Google Patents

Description

H. H. BLACHE.

COOLING 0F PISTONS AND PISTON RODS.

APPLICATION FILED FEB. I4. 1922.

jmnggf, mme@ Apr. I8, w22.

NETE@ STATES enfreint ernten,

-EANS lil n "f 1 BLACKS," 0F HELLMUP, NEAR COPENHAGEN; DWK.

CGDLING 0F PISTNS AND JPESTON RODS.

Specicationof Letters Patent.

Patenten een te. rena,

Application ledrliebruary 14,1922. Serial' No. 536,561.

hagen, Denmark,.have invented certain new s and useful Improvements Relating to the Cooling of Pistons and Piston -fRods, vof which the following is a specifcatlon.

rllhis invention relates to internal combustion engines and more partlcularly to double-acting internal combustion-engines of the type in which a hollow piston 1s cooled b the circulation of oilor other cooling medium through the piston rod and hollow piston, the oil being supplied to the piston` rod through the crosshead from a port or ports in the crosshead guide. v

Heretofore it has lbeen proposed to provide the crosshead with inlet and outlet channels, communicating with corresponding ports in the crosshead guide. ln suchcase the channels in the crosshead must be of such a length as to uncover the ports in the lcrosshead guide during the full stroke of the piston in order to ensure the uninterrupted supply and escape of the coolingpmedium, which is supplied to the engine vunder pressure. t

The object of the present invention is to create the circulation of the cooling -medium through the piston and piston rod by the accelerating and retarding action of the moving parts and without the necessity of supplying the cooling medium under pressure, which is ordinarily necessary in order to overcome the accelerating and retarding action on the cooling medium.

According to the present invention the crosshead only uncovers the port or ports in the crosshead guide during more or less of the outer part of its stroke, so that the said port or ports are only open 4for admission of the cooling medium to the piston during the louter part of the stroke of the piston, the outlet being open the whole stroke. By this meansl the acceleration and retardation of the parts creates a circulation 'of the oil through the piston and piston rod.

Tn order that the invention may be more clearly understood, reference is hereinafter made to the accompanying drawing showing one construction of the cooling means by way of example. v

Fig. 1 is a longitudinal section showing a double-acting internal combustion engine and Fig. 2 is a corresponding view showing the piston, piston rod and crosshead removed from the en ine. Figs. 3 and 4 show a modified form with a valve placed 4in the supply-pipe.

rlhe crosshead a is connected to the piston rod b which carries a piston, the latter being preferably made in two parts', an outer hollow part c and an inner hollow part d. The inner part d of the piston is provided with a tubular extension or sleeve e which surrounds the piston rod b and entends from the piston beyond a stuffing box f into e the crank-housing z. The sleeve e does not transmit the thrust of the piston to the crosshead a2 but loosely surrounds the piston rod b,form1ng an annular chamber m around the piston rod. rllhe sleeve c is of'such a length that its inner end is situated within the enclosed crank housing z' even when the piston is at the end of its out stroke, i. e. in the position shown in Fig. 1. The sleeve e is formed at its inner endwith a Hange g which forms a tight iit with the piston rod, and the sleeve e is also provided near the fiange g withv a plurality of holes h connecttition which is provided with a pipe 7c of suitable` length extending into the outer part c of the piston and thereby forming a connection between theV inner and outer chambers of the piston. An extension of the sleeve e within thehollow part d? of the piston7 provides a channel or channels Z opening laterally into the inner chamber of the piston and thus connecting the latter with the interior of the enclosed crank casina- 'llhe cooling medium is supplied throu h av pipe a which opens into a port a in t e crosshead guide, the crosshead a being pro-l vided witha recess or channel o adapted to register with the port n. The channel 0 does not extend the whole len h of the crosshead, but is only'of such a ength that the supply pipe n' is uncovered during more or less of the outer part of the stroke of the piston i. e. from the position of the piston shown in F ig. 1 half the way or less than half the lway of the stroke before and after this position. The channel o communicates by way of a pipe p with a central bore y in the piston rod b in such a manner that the cooling medium is sup-plied by the channel o to the outrjchamber c of the piston..

The arrangement is such that when the crosshead a is in the position nearest the engine cylinder, it uncovers the supply pipe i reaches the middle of its stroke.

When the piston is reciprocating between its' middle position and top dead centre, the direction of the retarding .and accelerating forces, which act on the coolino medium within the piston and piston rord; *will be that indicated by the arrow A in Fig. 1, and in consequence thereof the cooling-oil will collect as shown at 7' and s (Fig. 2) within the piston and extend along the annular chamber m to such a level as that indicated by the letter t in Fig. 2.

During this period the cooling medium will fio-w through the pipe from the inner chamber d to the outer chamber 0 of the piston. As soon as the piston has passed the middle of its stroke and is reciprocating between its middle position and the bottom dead centre, the acceleratinoq and retarding forces on the cooling-oil will act in the opposite direction to the arrow A. During this period the supply pipe n for the cooling-oil is cut off from the channel 0 in the crosshead, thereby preventing the back flow of the cooling medium into the supply pipe n. The cooling medium may, however, flow from the outer chamber c of the piston into the inner chamber d through the pipe 7c, and from the chamber d through the ducts Z into the annular chamber m, and from thence through the openings h into the enclosed crank housing. The warm cooling medium will therefore be ejected from the annular chamber m, but a suiiicient quantity will be left in the piston owing to the length of the pipe c and owing to the fact that the ducts Z are disposed at adistance from the transverse partition separating the chambers c and d. Every time the piston reciprocates through the outer part of its stroke, fresh cooling medium will be suppliedy through the pipe n, and when the piston is reciprocat- 4 ing .through the inner part of its stroke, a proportional quantit of warm cooling meium will be ejecte through the annular chamber m into'the enclosed crank housing. A suitable quantity of cooling liquid will always be retained in the two chambers of thepiston, and on account of the reciprocatory motion, this cooling medium will always be in violent motion and will thus be splashed upon the hot walls of the piston.

It is necessary that the crosshead shoe, if the engine ,is to be used for a long stroke, should be of considerable length, as the crosshead shoe in all its positions must cover the supply-opening 'n' for the cooling medium.

Misses Such an elongated crosshead shoe necessitates increased first cost in the manufacturing, besides which the engines will be of increased length and weight. The modified form shown in Figs. 3 and 4 does away with the above mentioned drawback by the use of a cross-head shoe of normal len-gth, whereas there is arranged in the supp-ly pipe for the cooling medium al cut-off device, for instance a rotating valve, which is driven from the shaft of the engine by means of a chain or'the like.

In Figs.- 3 and 4 is shown a constructional form. Fig. 3 shows a longitudinal section through the crosshead and the guide planes for same. Fig. 4 shows a section through the valve placed in the supply pipe.

In the drawing 1 designatesl the cross head shown in the position nearest to the crank shaft, 2 shows the crosshead in the dead point position nearest the cylinder. o designates the recess in the crosshead shoe a and n is the supply pipe for the cooling medium. In the position 2 for the crosshead, the supply port o communicates with the" recess o which through thepipe p is connected to the boring g in the pistonrod b in the manner set forth. The crosshead shoe a has, as shown in the drawing, such a length that the cross-head shoe covers the port c, when the crosshead moves away from the cylinder, somewhat over the middle part of the stroke.

Between the supply pipe n and the part o is placed a cylindrical casing .fr containing the rotating valve y and said valve is provided with an opening .c which is adapted to register with the port o. The valve is actuated by means of its stem u, which eX- tends through the valve-casing and is provided with a sprocket wheel w, to be drlven by means of a chain from the engine shaft, in such a manner that the valve makes the same number of revolutions as said shaft. T'he opening a in the valve is made of a suitable length to enable it to be open to supply the oil during that part of the stroke where the crosshead shoe with its oil-channel o covers the supply port o, while the rotating valve shuts off the port o before the crosshead shoe uncovers said port.

1 claim:

1. An internal combustion engine, comprising a hollow piston having inner and outer internal chambers, and a transverse partition therebetween, a cylinder wherein the piston works; a hollow piston rod connected to said piston and opening at one end of its bore into the outer piston chamber; and means for supplying a cooling liquid to the other end of the piston rod bore for passage therethrough and through said outer chamber, said partition having means for enabling the passage of the cooling liquid therethrough from one chamber to. the other alternatelydn lopposite direcfor supplying a cooling liquid to the other end of the piston bore for passage there; through into the outer chamber; the inner chamber having an outlet for the liquid;

and a tube extendingvfrom the outer chamber through the partition into the inner chamber to deliver the liquid from one chamber to the other alternately in opposite directions, said tube having that a quantity of the liquid is always retained in the outery chamber. v

3. An internal combustion engine, coinprising a hollow piston having inner and outer internal chambers,4 and a transverse.

. partition between them; a hollow piston rod connected tothe piston and opening at one end ot its bore into the outer chamber; a cylinder wherein the 'piston works; means for supplying a cooling liquid'to Vthe other a length suchv end of the piston` bore for passage therethrough into the outer chamber; and a tube extending from the outer chamber through the partition into the inner chamber to deliver the liquid from one chamber to the other alternately in opposite directions, the

inner chamber having a plurality of outlet ports for the liquidv which are spaced from said partition to insure a quantity of 'said liquid always being retained in that chamber.

4l. An internal combustion engine', comprising a hollow piston; a cylinder wherein the piston works; a crosshead connected to the piston; a crosshead guide provided with an inletport; a delivery pipe communicating at one end with the interior of the hollow piston and opening at the other end through the crosshead to be' brought into and out of communication witlisaid port; a supply pipe leading to said port f for supplying a cooling medium thereto;

and a rotary cut-0H valve associated with the supply pipe and adapted to automatically shut O' the flow of the cooling medium when the head, f y

lln testimony whereof ll ailix mysignature.

i HANS l-lE-NRIK BLACHE.

port is uncovered bythe cross-

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