US1262823A - Expansion-valve. - Google Patents

Description

EXPANSION VALVE. APPLICATION FILED nic. 21. 1910.

,11,z62231 111151110211 Apr. 16, 1918.

QQ w l v UNITED STATES PATENT OFFICE.

JOSIAH L. MERRILL, OF PITTSBURH, PENNSYLVANIA, ASSIGNOR T THE GENERAL REFRIGERATION COV., A. CORPORATION OF OHIO.

EXPANSION -VALVE Specification of Letters Patent. @Patented Apr., 16, 1918.

Application filed December 21, 1910. Serial No. 598,544.

A the following being a full, c ear, and exact disclosure of the one form of in invention which I at present deem prefera le.

For a detailed description of the present forni of my invention, reference may be had `to the following specification and the .ac-

coinpanying drawing, which shows my screw of the adjusting needle (l.

valve partly in section.

Mv invention relates to valves employed to allow the passage, from a compression chamber into a space of lower pressure, of a gas such as anhydrous ammonia or other gas employed7 for example, in refrigeratiiig apparatus.

The usual practice in such valves has been to forni the small opening through which the gas flows in a disk of comparativel thin metal, the result being that it is di tieult to expand the gas down to a very low pressure, because on the outlet side there is formed in the disk a zone or circle of chilled metal surrounding theopcning but at a slight radial distance from the openin itself. This zone of chilled metal cuts o the transmission of heat through the metal of the disk to the edges of the opening and the opening becomes wholly 'or partly closed by frost and ice in the course of any long continued operation. lt is my intent to rovide a valve for the expansion of sma ler amounts of material than has heretofore been possible in continuous operation. To that end I form the valve opening as a duct of considerable length through metalgof a thickness, measured along the duct greater than the penetrating'eifect of the chi l produced by the expanding gas on the outlet side of the duct. Moreover, I give this duct a, gradually in'creasin the refrigerat-ing effect along the length of the duc'.. This also serves to convert the pressure of the gas into velocity on the principle of the expanding nozzle Y in a steam turbine. This tends to .produce a blast .which will dissipate any particles of ice or frost that tend to form and prevent their accumulation in or around the extremity of the duct. There is also a Smooth area from its inner Y to its outer end.. Bv t iis means I distribute and gradually enlarging passageway from the Aorifice outward which tendsto prevent -local eddies in the outward flow of the stream such as might result if 'the space were of pocket forni, or had subsequent restrictions or internally projecting shoulders. Such eddies would tend to concentrate the chilling effect on the walls near to the needle aperture.

Referring to the drawing, A represents the body of my valve. B is an interior bushing seated against a shoulder in the bore of the valve and forming a nut for the Back of the bushingr is a washer I) and back of the washer is the space for the usual packing,

held in place by nut E. The gas enters the val ve by a passano G. f

At the'extrennty of body A. isa projection F in which is formed the escape opening for the gas in the forni of a. duct ll passing through the projection F and flared or enlarged toward its outlet end. Through this duct'H the high-pressure gas vin the body of the valve is allowed to escape into the low pressure space outside. The expansion of the gas will`begin at the entrance to` the duct and will continue as it passes .through the duct in proportion to the enlargement in its' cross area.

This will distribute the chillin or refrigerating effect of the expansion a ong the entire length of the duct and prevent its concentration at a particular point. vAt the saine time the mass of metal around the duct is of s uch length that the external chill around the openimg' will not penetrate back along the duct far enough to eilt off the conductivity of the metal around the throat of the duct.

From this it will be seen that the ressure on the iuld entering the passage is converted into velocity as said fluid passes through'the duet H, the velocity of the gases carrying the frosting point well beyond the valve. It will be noted that the taper of the duct H is so proportioned to the length of the duct that the maximum expansion of the fluid vis obtained at ,tlieirear extremity thereof.

What claim as, new and desire to secure by Letters Patent is:

1. An expansion valve for refrigeratiiig systems comprising ay body having an inlet passage and an outlet duct communicating with said passage through a minute orifice,

the size of which is definitely proportioned to the size of the inlet passage to maintain pressure in the latter, said outlet duct being elongated and flaring from said orifice "whereby the frost-ing point is carried beyond the valve by the velocity of the refrigerating gas, the thickness of the metal, measuring along theductz being greater than the penetrating e'ect of the chil-l produced by thev edjdying` back of the expanding gas on the outlet side of the duct against the surrounding metal, and a valve controlling said orilice.

2. An expansion lvalve for refrigerating systems comprising a body having an inlet passage and an outlet duct communicating with said passage through a minute orifice, the size of which is deinitely proportioned tothe size vofathe inlet passage to maintain pressure inthe latter,

said body being provided with an extension through which the outlet duct extends longitudinally, the outlet duct being elongated and lHaring from said oriiice, whereby the frosting point is carried beyond the valve by the velocity of the refrigerating gas, the thickness of the metal, measuring along the duct, being greater than the penetrating effect of the chill produced by the eddying back of the expanding gas .on the outlet side of the duct against the surrounding irnetal7 and a Valve controlling said orifice.

in witness whereof l have hereunto set my hand, before two subscribing witnesses, this 12th day of December, 1910.

JOSlAl-I L. MERRILL.

Witnesses: Y

D. E. MITCHELL, llt. E. (irmvns.v

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