US755317A - Compressor-valve. - Google Patents

Description

No. 755,317. PATENTBD MAR.22,1904. s. A. REEVB.

COMPRESSOR VALVE.

APPLICATION FILED HAB.. 21, 1901.

H0 MODEL. 2 ETS-SHEET 1.

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No. 755,317.l 'PATENTBD MARQzz, 1904.

s.4 A. BREVE. COMPRESSOR VALVE;

v APPLICATION FILED KAB. 21. 1901. N0 MODEL.

2 SHEETS-SHEET 2.

EISSEIS 0.0%@ @ai j@ v UNIT-ED STATES j Patented March 22, 19014.v

.PATENT OFFICE.

` SIDNEY REEVE, OE WORCESTER, MASSACHUSETTS, ASSIGNOR TO CHARLES E. BROWN, TRUSTEE, READING, MASSACHUSETTS.

COMPRESSOR-VALVE.

SPECIFICATION forming part of Letters Patent N0. 755,317, dated March 22, 1904.

` Application iiled March 21, 1901.

To all whom t may concern:

' Be it known that I, SIDNEY A. REEvE, of Worcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Compressor- Valves, of which the following is a specification.

This invention relates to gridiron-valves controlling the admission or'discharge' of an elastic-Huid compressor; and it has for its object to combine certain advantages of both automatic or self-acting valves and positivelyoperated valves.

With this end in view the invention consists in devices hereinafter described and claimed for combining a positive closing of the valve with an automatic or self-timed opening, for obtaining an ample andv quick opening, andv for minimizing friction of entrance and exit of air.

Of the accompanying drawings, forming a part of this specification, Figure 1 represents a longitudinal sectionalview of a compressor provided with admission and discharge valves constructed in accordance with my invention,

i the section being taken in a plane which shows the admission valves and their operating mechanism. Fig. 2 representsva section on the line 2 2 of Fig. 1 on a larger scale. Fig. 3 represents a longitudinal section of one end of the cylinder, taken in a plane which shows thedischarge-valve. Fig. 4 represents a transverse section showing a charge-valve.

The same reference characters indicate the same parts 'inail-of the figures.

Referring to the drawings,"1 represents a modifiedfform of 'disfl compressor-cylinder,having a piston 2, actuber 2 3 and a discharge-chamber 18.

ated from a crank-shaft 3. Outside of the cylinder-head 'L1 at each end is an inlet-cham- Each cylinder-head is providedv with a set of gridiron admission-ports 5 5, controlled by a gridiron slide-valve 6, mounted upon the inner side of the cylinder-head and having a valve-stem 7,

lat the outer end of which is secured a piston 8, operating in a dash-pot cylinder 9. The Vsaid dash-pot cylinders 9 are connected by links 10 10 with wrist plates or levers 11 11,

Serial No. 52,148. (No model.)

pivoted to xedsupports, and said wrist-plates are connected by links 12 12 with a threearmed lever 13, oscillated by an eccentric 15 on the crank-shaft 3 through an eccentric-rod 14. In each dash-pot the cylinder-space above the piston 8 is provided with a vent-outlet 16, Whose orifice is controlled by a vent-valve 17,

Aand betweenthe piston 8 and the lower head of the dash pot cylinder is interposed a spring 17 O. Y n

The operation of the admission-valves is as follows: The wrist-plates 11 11 tend to impart such reciprocating movements to the valves 6 6 aswould fully open each valve as the piston starts to recede from that end of the cylinder and fully close said valve when the piston has reached the opposite end of the cylinder and a cylinder full of elastic iiu'id has been admitted through the'ports 5. At the beginning of the admission-stroke, however, just before the piston starts to recede and reexpand the clearance fluid remaining in the cylinder from the previous compression-stroke this clearance fluid creates an excess of pressure within the cylinder over that externall vacting on the inner side of the valve 6 tends to hold said valve to its seat by friction and prevent its opening after the wrist-plate 11 has started on its valve-opening movement. The wrist-plate starts on its valve-opening movement at orl just before the moment when the piston 2 reaches its dead-point. The

dash-pot cylinder 9 therefore. starts to move upwardly, while the ,piston 8 remains substantially stationary, and the spring 170 is thereby put under compression, which increases as the movement of the wrist-plate continues. As the piston recedes, however, the pressures on opposite sides 'of valve 6 approach a balance. and the static friction between the valve and its seat decreases until a point is reached at which the tension of the spring 170 overcomes suchV friction and causes the valve to open. A sudden and full opening of the valve then occurs, and the inertia acquired by the valve under the influence of spring is overcome by the compression created by the dash-pot piston 8, which comj pression may be regulated by varying the orifice of the vent 16. When the time comes for closing the valve 6, the friction due to unequal pressures on the valve is absent, and there is a positive timing of its closing movement effected by an actual meeting of the piston 8 with the upper head of the dash-pot cylinder or by a slight air-cushion between the two.

In the case of the discharge-valves 24 24 the valves are located on the outside of the cylinder-heads within the discharge-chambers 18.l

The -valve mechanism for operating these valves is not shown in full, being a duplicate of that for operating the admission-valves 6, with the exception that the eccentric is so located as to tend to open each valve at or after the beginning of a compression-stroke and close it at the end of said stroke. At the beginning of the compression-stroke when the valve is closed the pressure in chamber 18, being greatly in excess of the pressure within cylinder 1, holds the valve 24 by friction in close position against its seat. The outward movement of the dash-pot cylinder 9 under the infiuence of the wrist-plate begins at such a time as to be well under way by the time the compression in cylinder 1 equals the pressure of the exhaust-chamber 18, which is that of the system which the compressor supplies. The valve therefore receives a quick and ample opening, which is automatically timed, according to the degree of compression which exists. Its closing movement is positively timed and may occur with more or less aircushion in the dash-pot.

The principal advantages of my gear are- First, automatic timing for the valves opening,.with positive -timing for its closing.

Second, rapidity of opening, due to the accumulation of motive forces previous to the instant when the valve starts into motion. It is plain that the longer the opening is delayed, as would be the case with discharge-valves working against a heavy head-pressure, the morerapid will be the opening, lbecause of the increased previous accumulation ofv motivey force. In this respect the gear is an improvement over both positively-moved and automatic discharge valves, for the former, whether operated by eccentric, cam, or other similar means, finds its maximum possible velocity lessening as the time of opening in the stroke becomes later, and the latter, although opening more sharply and quickly under the conditions stated, is apt to have its accuracy of closing impaired by this delayed accentuated opening.

Third, amplitude of opening. In this respect all positively-moved valves are superior to automatics; but my invention is superior to other positively-moved valves in that with them the maximum opening of the valve must occu1` at or about half-way between opening and closing, whereas the maximum demand for opening occurs at the instant of opening, for then is the piston moving most rapidly. In my gear in the case of discharge-valves, to which this paragraph chiefly refers, the maximum opening occurs at the instant of opening, the valve Abeing afterward slowly pushed shut in keeping with the diminishing motion of the piston as it nears the end of its stroke. It is further true of other positive valves that the maximum amount of opening available from a given amount of motive mechanism must decrease as the time of opening is delayed.' This is much less, and sometimes not at all, true of my valve-gear.

Fourth, preservation of the automatic character of the valve when called upon to open at times when the positive gear connected with it declares it time for being closed and when, with other valves, it would force the valve to ,be shut. By using an unbalanced valve not rigidly connected to the eccentric it is free to open of itself Whenever called upon to do so. f

In Fig. 4 I have shown an annular arrangement of ports and valves, 1 representing the stationary cylinder-wall, having ports 5 5 disposed circumferentially around it, and 19 an annular gridiron discharge-valve adapted to oscillate upon the cylinder to open and close said ports. Opposite sides of this valve are connected by links 2O 20 with a rock-lever 21, which is oscillated by a rod or stem 22, having connections similar to those of the stem 7. In the case of an admission-valve the valve would be placed on the inside of the cylinder.

I claim- 1. In an elastic-fluid compressor, the combination of a compression-cylinder having a gridvalve seat, a grid-valve mounted on said seat, said valve and seat having relatively sliding frictional holding-surfaces adapted to be held together by a difference in the pressures on opposite sides of the valve, positively-moving valve-operating mechanism, and valve-opening resilient means interposed between said mechanism and the valve and brought into opposition to the holding effect of said surfaces by the action of said valve-operating mechanism for permitting a variation in the time of opening the valve.

2. In an elastic-liuid compressor, the combination of a compression-cylinder having a gridvalve seat,a grid-valve mounted o n said seat, said valve and seat having relatively sliding frictional holding-surfaces adapted to be held together by a difference in the pressures on opposite sides of the valve, positively-moving valve-operating mechanism, a valve-opening spring interposed between said mechanism and the valve, and brought into opposition to the holding effect of said surfaces by the action of said valve-operating mechanism and a dashpot for cushioning the valve-opening movement produced by said spring.

3. In an elastic-fluid compressor, the combi- IOO IOS

IIO

nation of a compression-cylinder having` a gridopening spring interposed between said mechvalve seat, a grid-valve mounted to slide on said anism and the valve. I0 seat and adapted to be held thereto by a dilei. In testimony whereof I have axed my sigence in the pressures on opposite sides of the nature in presence of two witnesses.

valve, positively-moving valve-operating SIDNEY A. REEVE. mechanism, a dash-pot having members posi- Witnesses:

tively attached respectively to and movable v R. M. PIERsoN,

with said mechanism and the valve, and avalve-A C. K F. BROWN.

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