US1949179A - Production of solid carbon dioxide - Google Patents

Description

Feb. 27,. 1934. R. c.- PIERCE 1,949,179

PRODUCTION OF SOLID CARBON DIOXIDE Filed Sept. 15. 1930 2 Sheets-Sheet 1 amy# Fb. 2?', H934. R. c. PIERCE PRODUCTION OF SOLID CARBON DIOXIDE Filed Sept.

l5. 1930 2 Sheets-Sheet 2 gwmzlntoz G. 591m g Patented Feb. 27, 1934 UNITED sTATEs PRODUCTION OF soLm CARBON DIoXmE Raymond C. Pierce, Bronxville, N. Y., assgnor to York Ice Machinery Corporation, York, Pa., a corporation of Delaware Application September 15, 1930 Serial No. 482,105

6 Claims.

This invention pertains to the production of solid carbon dioxide, and more particularly to shaking mechanism for freeing the snow from a foraminous bag into which liquid CO2 is expanded to form the solid carbon dioxide.

The invention further relates to apparatus for compressing the snow shaken from the bag to form relatively dense blocks of the solidified material. The snow press is associated with the in expansion chamber of the apparatus in such a way that continuous expansion of liquid CO2 is permitted While the snow press is operating.

The usual method of producing solid CO2 includes the steps of compression and liquefaction of the CO2, followed by expansion of the liquid in a chamber in which a portion of the expanded liquid solidies in the chamber, the remainder ilashing into the gaseous state, after which it is returned to the compressor. In some appagn ratus a foraminous member is interposed between the expansion nozzle and the outlet from the chamber, in which case it is necessary periodically, or continuously, to remove the snow-like solid CO2 from the sides of the foraminous member. The snow,l then falls into a chamber from which it is removed and compressed.

One of the objects of this invention is to provide a shaking mechanism acting on the exterior of a flexible pervious bag interposed between the expansion nozzle and expansion chamber outlet.

Another object of the invention is to provide direct communication between the interior of the snow-bag and the snow press, the press plunger being so guided with respect to the passage between the press and the snow bag that the expansion chamber is closed during ejection of the compressed snow.

A further object is the provision of a closure for the press, the same being held in closed position by hydraulic pressure until the snow has been compressed a predetermined degree, after which the closure is opened to permit ejection of the formed block.

'The invention will be better understood from the following description, reference being had to the appended drawings, in which:

Fig. l is a sectional elevation of the expansion chamber and snow press, together with the hydraulic piston controlled closure for the press.

Fig. 2 is a partial sectional elevation taken on the line 2-2 of Fig. 1. x

Fig. 3 is a perspective View of the bag shaking mechanism.

Fig. 4 is a plan View of the entire apparatus.

Referring to the drawings, liquid CO2 is admitted to the expansion chamber 1l through pipe 12, interchange coil 13 and either or both of the expansion nozzles 14 and 15 controlled by valves 14', l5. It is to be noted that nozzle 14 is directed toward the forward end of press chamber 16, the reason for this arrangement being that it is desirable that the snow be well distributed in the forward end of the press chamber before actual compression Athereof is begun. Solid carbon dioxide in the form of snow does not "ow readily, that is, voids or irregularities are not entirely eliminated by compression of the snow. By continuously directing the snow forwardly in the press chamber the likelihood of the voids and irregularities referred to is minimized.

Interposed between the outlet 17 of the expansion chamber and the nozzles 14 and 15 is a foraminous member 18, in the present instance a I flexible pervious bag. The bag is tubular in form and is secured at its upper end by a ring 19 75 to an annular flange 21 on the chamber head 22. At its lower end the bag is fastened to angle pieces 23 which in turn are secured to the press chamber 16. The angle pieces form a frame which conforms with the shape of the passage B0 24 between the snow-bag and the press.

While some of the snow formed by expansion of the liquid CO2 is immediately directed to the press chamber, much of it follows the expanding gases and adheres to the sides of the snow-bag 18. To prevent clogging of the pores of the bag, as well as to utilize all of the snow,

4mechanism for continuously shaking the bag is provided. This mechanism comprises a frame 25 surrounding the bag and having a perimeter sub- 00 stantially equal to that of the bag. The frame is preferably, although not necessarily, rectangu-l lar, as shown in Fig. 3. Pivotally supported on standards 26 secured to the angle pieces 23 are a pair of bell-crank levers 27. One end of each of the bell-cranks is pivoted to the shaker frame 25, while the other end of each bell-crank is slotted at 28, to accommodate a cross-pin 29 on one end of connecting rod 31. .The connecting rod is provided at its other end with a slotted head 32 cooperating with the crank shaft 33 journaled in bearings 34 on the base 35. The crank shaft is driven by a motor 36. It will be seen that rotation of the crank shaft reciprocates connecting rod 3l, causing a similar reciproca- 105 tionof the frame 25. This reciprocation effects vigorous shaking of the bag and dislodges the snow that has adhered to the porous structure of the bag. The snow then falls by gravity through passage 24 into the press.

The snow press comprises a plunger 37 slidable in and cooperating with chamber 16. For convenience, the chamber 16 will hereinafter be referred to as a cylinder, although it is illustrated as being substantially square. Obviously, the plunger and cylinder may be made to conform with the cross-section of the desired shape of block, depending on the particular use for which the snow blocks are intended. The forward end of the cylinder is closed by a removable closure 38 held in closed position during the compression stroke of the piston by hydraulic pressure exerted on piston 39 in cylinder 41. Closure 38 and piston 39 are secured to opposite ends of the piston rod 42.

Plunger 37 is reciprocated by pistons 43'in cylinders 44, one on each side of the press and connected to the plunger by piston rods 45 and cross head 46. A source of hydraulic pressure, either an accumulator or pump 47, is connected by pipes 48, 49, to the closure operator cylinder 41 and plunger operated cylinders 44 respectively. Branch pipes 51, 52, lead to opposite ends of cylinders 44 to provide for actuation of the plunger in either direction and are controlled by a multi-way valve 53. Pipe 48 communicates with only one end of cylinder 41, the other end of which is vented at 54. Interposed in the pipe 48 is a two-way valve 56 to permit cylinder 41 to communicate either with the source of hydraulic pressure 47 or with a discharge pipe 57. Discharge pipes 57, 58 communicate with a sump or other receiver (not shown). IThe press cylinder 16 and expansion chamber 11 are covered with heavy insulation 59 to prevent heat transfer during the operation of the apparatus.V

In the operation of the press, the snow is dislodged from the bag and directed forwardly in cylinder 16 by the curved nozzle 14. When a sufficient amount of the snow, usually determined by 4experiment and dependent on the time elapsed between reciprocations of the-plunger, has been accumulated in the press cylinder, the valve 53 is turned to effect forward movement of the plunger 37. Closure 38 is held tightly against the cylinder by the hydraulic piston 39 during compression of the snow. When the snow has been sufficiently compressed, the pressure on piston 39 is relieved, whereupon the closure 38 will yield to the pressure exerted on the snow by plunger 37. It is to be noted that the fluid pressure acting on plunger 39 is uni-directional so that after uid pressure on the piston is relieved forward movement of the piston can be effected only by the imposition of pressure transmitted through the snow from plunger 37. As the compressed snow is extruded from the end of the cylinder, it is supported frictionally between closure 38 and plunger 37. the latter continuing its forward movement until it has reached the end of the cylinder. It is apparent that the compressed solid carbon dioxide will be ejected in the form of a block which is readily removed when plunger 37 has completed its forward stroke.

As shown in Fig. 1, the length of passage 24 between expansion chamber 11 and press cylinder 16 is considerably less'than the length of the press cylinder. Coincident with the extrusion of compressed snow from the press, plunger 37 is moved forwardly a distance sufficient completely to cover passage 24 and act as a valve to prevent escape of gas from the expansion chamber through the open press. It is, of course, necessarytomoveclosure38intocontactwiththe open end of the press and with plunger 37 before the latter is returned to its rearward position in the press. Substantial exclusion of air from the press cylinder is thus possible. It is apparent,

therefore, that the plunger and closure not only prevent escape of gas from the expansion chamber, but practically prevent entrance of any air to the apparatus, at the same Itime permitting continuous operation of the press. The iiash gas is thus returned to the compressor substantially as delivered to the expansion nozzle, that is, with little or no contamination from air leakage. Also, by excluding air, the gas is'maintained at an extremely low temperature to insure maximum pre-cooling of the liquid CO2 in the regenerative coil 13 around which the expanded gas iiows before leaving the expansion chamber.

A preferred form of the invention has been illustrated, but modications thereof are contemplated Within the limits defined in the claims.

1. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and an outlet therefrom; a flexible pervious member interposed between said nozzle and outlet for intercepting solidified carbon dioxide; and means for continuously shaking said member.

2. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and an outlet therefrom; a flexible pervious member interposed be` tween said nozzle and outlet for intercepting solidified carbon dioxide; shaking means cooperating with said member; and means for reciprocating said shaking means.

3. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and outlet therefrom; a flexible pervious member interposed between said nozzle and outlet for interoepting solidied carbon dioxide; shaking means cooperating with said member exteriorly thereof; and means for reciprocating said shaking means.

4. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and an outlet therefrom: a tubular flexible nervious member interposed between said nozzle and outlet for intercepting solidified carbon dioxide; a frame having a. perimeter substantially equal to that of said member and surrounding said member; and means for reciprocating said frame.

5. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and an outlet therefrom; a tubular flexible pervious member interposed between said nozzle and outlet for intercepting solidied carbon dioxide; a press chamber having a passage adjacent one end thereof communicating with the interior of said member; and means for shaking said member, said expansion nozzle being so disposed in said member as to direct solid carbon dioxide formed on said member and shaken therefrom by said shaking means toward the 'other end of said press chamber.

6. In an apparatus for the production of solid carbon dioxide, an expansion chamber having an expansion nozzle therein and an outlet therefrom; a tubular iiexible pervious member interposed between said nozzle and outlet for intercepting solidiiied carbon dioxide; a press communicating with and underlying said member; and means for shaking said member.

RAYMOND C. PIERCE.

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