US2025489A - Still - Google Patents

Description

Dec. 24, 1935.

G. F. ZELLHOEFER STILL Original Filed Jan. 12; 1933 INVENTOIL GLEN/V 1 ZELLHOEFEE ATTORNEY.

. 24, 1935. e. F. ZELLHOEFER STILL 2 Sheets-Sheet 2 Original Filed Jan. 12 1935 m R m# 4 L m; 5 1 F M E 4 6 A TTORNE Y.

Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE STILL Glenn 1*. Zellhoefer, Bloomington, n1.

Original application January 12, 1933, Serial No. 651,306. Divided and this application July 20,

1934, Serial No. 736,233

1 Claim.

, refrigerant from the solvent; a condenser to condense the gaseous refrigerant to a liquid state; an evaporator in which the liquid refrigerant is vaporized at reduced pressure; an absorber in which the gaseous refrigerant is dissolved in the solvent; a system of heat exchange; and means effecting or causing circulation.

This invention relates more particularly to improvements in such a still and is a division of this applicants application Serial No. 651,306, filed January 12, 1933.

With these and other objects in view, reference is made to the accompanying sheets of drawings which illustrate an embodiment of this invention with the understanding that the invention is not limited to the embodiment shown and that minor detail changes may be made therein without departing from the scope thereof.

In the drawings:

Figure 1 is a diagrammatical view illustrating the various elements included in this improved non-intermittent absorption plant with the connections therebetween whereby the cycle of operation may be followed.

Figure 2 is an enlarged detail view in central longitudinal vertical section of the improved type of still.

Figure 3 is a view in transverse section taken on the line 33 of Figure 2, looking in the direction of the arrows.

Figure 4 is a similar view taken on the line 4-4 of Figure 2, looking in the direction of the arrows.

Figure 5 is a detail sectional view taken on the line 55 of Figure 2, looking in the direction of the arrows.

In the refrigeration plant disclosed herein, it is preferable to employ chlornaphthalene as the solvent and methyl chloride as the refrigerant. The solution of the refrigerant in the solvent, commonly called strong liquor, is accomplished in the absorber A and is removed therefrom by the mechanically operated pump P and caused to circulate through the heat exchanger X and preheater H to be discharged through the top of the still S,- as shown in Figure l. A steam boiler B provides steam for heating the preheater H and heating the still S wherein the refrigerant is distilled off the solution and passes through rectifier F and through the condenser C to the receiver D and from thence through an expansion valve to the evaporator E from which the 10 refrigerant in gaseous form is returned to the absorber. The pressure created within the still during the distilling operation returns the solvent from which the refrigerant has been distilled, commonly called weak liquor, through a 15 heat exchanger and a residual heat coil G to the absorber. Return lines are provided from the heat exchanger and preheater to the steam boiler and water jackets are provided about the rectifler F, condenser C, receiver D, as shown, as well as water Jackets about the residual heat coil G,

and the absorber A.

Inasmuch as neither chlornaphthalene or methyl chloride are non-corrosive toward iron, brass, copper and bronze, consequently, cast-iron parts and flexible copper tubing may be employed in this apparatus facilitating ease in manufacture and service. It is preferable that the pump P be of the turbine type and mechanically operated by a motor, not shown, to positively circulate the strong liquor from the absorber through the small tubes of the heat exchanger and preheater at a high velocity. The high velocity of the strong liquor through the small tubes makes it possible for a rapid transfer of heat through the heat exchanger and preheater. In practice, it has been found that a velocity of approximately four feet per second has proven satisfactory for this purpose without excessive power consumption. To obtain such a velocity of the strong liquor without a mechanically operated pump would require a head of approximately thirty or forty feet which would be impracticable in practice.

By providing a mechanical positive circulation in the manner described, a low-side in the system is created on the intake side of the pump and a high-side on the discharge side of the pump. By means of the pump P, the cycle of this absorption system is non-intermittent as long as refrigeration of a predetermined temperature is described to be produced in the evaporator.

The still S is preferably formed to include a metallic cylinder I having end closures 2 mounted on the axial supports 3 engaged by legs 4 to support the cylinder in horizontal position. A convex cylindrical casing 5 of less diameter than the cylinder I closed by a flat plate 6 is mounted to rest uponthe bottom of the cylinder I in contact with the end closure 2 at the left hand end and a similar casing 5" with a similar closure 6, facing the closure 6, is secured adjacent to the opposite cylinder closure 2 and in contact with the upper side of the cylinder I as shown in Figures 2, 3, and 4. A series of parallel tubes I arranged in the same plane connect the upper portions of the casing 5 and 5, passing through the plates 6 and 8 to afford a means of communication between the interiors of said casings. Inasmuch as the upper end of plate 6 is spaced apart from the top of cylinder I and the upper part of plate Ii is in contact with the cylinder I, the pipes I will be inclined downwardly Another series of pipes 8 are arranged to communicate through the plate 6 to the interior of the casing 5 adjacent the entry of the pipes I and pass through the plate 6* approximately at its horizontal diameter whereby the pipes 8 slope at a greater angle and in the opposite direction from the pipes I. A pluraJity of pipes 9, preferably arranged in parallel rows extending from below the horizontal diameter of the plate 6 and in similar engagement with the plate 6, provide additional means for communication between the casing 5 and 5. The interior of the casing 5 is connected by the pipe I to the boiler B whereby steam is caused to pass through the series of pipes I, 8, and 9 into the interior of the casing 5, the bottom of which is connected by the pipe I I! through the return line to the boiler.

A trough I I is mounted in the cylinder I on the underside of the pipes I having upturned edges extending from the plate 6 and spaced apart at the other end from plate 6. A similar trough I2 is mounted below the pipes 8 extending from the plate 6 and spaced apart at the other end from the plate 8. A steam jacket I2 is placed about a portion of the exterior of the cylinder I connected by the pipe I3 to the boiler for supplying steam to the interior of the jacket which is provided at the lower end with a pipe I3 leading to the return line to the boiler, which steam jacket provides a preheater for the strong liquor which is passed through a series of coils I4 arranged within the steam jacket I2 discharging at I5 above the highermost part of the trough I I adjacent the top of the casing 5 The strong liquor passing through the coils I4 is preheated by the steam jacket I2, which is termed the preheater, and corresponds to the preheater H in Figure 1. The strong liquor passing through the discharge I5 travels down the trough I I over the steam pipes I, is discharged upon trough I2, and passes down this trough over the steam pipes 8 and is thence discharged to pass over the plurality of steam pipes 9 until it gathers at the bottom of the cylinder I. In passing over this series of steam pipes, the refrigerant is distilled off and the weak liquor gathers at the bottom of the cylinder. The gaseous refrigerant passes through the pipe I6 to the rectifier, hereinafter described, and the weak liquor passes through the discharge II at the bottom of the cylinder I and enters a small pipe I8 which is preferably coiled about the exterior of the cylinder I. This small pipe I8 passes through a similar coil I9 of greater diameter, one end of which 20 connects with one end of the coil I4 within the steam jacket or preheater I2 and the other end of which is connected by the pipe 2| to the discharge side of the pump P. The small pipe I8 leaves the larger coil as it joins the pipe M and passes through several coils I8 passing through larger coils 22 which form a water jacket thereabout, one end of which 23 is connected to a source of water supply 5 and the other end 22 constitutes the water outlet from the residual heat coil. That portion of the small coil I8 connected to the bottom of the still or chamber I and conducting the weak liquor therethrough which is surrounded by the larger coils I9 conducting the strong liquor to the still forms a heat exchanger.

The high velocity of the liquids passing through the relatively small tubes I8 and I9 of the heat exchanger affords much more rapid transfer of heat than can be effected by a series of tubes immersed in still or essentially still liquids. It is advantageous to pass the solution from the heat exchanger through a coil or system of coils I4 surrounded by a steam jacket I2 to preheat the solution before its entry into the cylinder I, since the transfer of heat from the steam to the solution is much more rapid by this method than by immersing a system of steam coils in the still or essentially still solution. Also the walls of cylin- 25 der I are utilized as heat transfer surface.

That portion of the small tube forming a coil I8 passing through the water jacket 22 removes the residual heat from the weak liquor; that is, the major portion of the heat represented by the difference in temperature between the weak liquor and that of the available water supply. The tube I8 conducts the weak liquor to the absorber from the residual heat coil. The still including the cylinder I and series of coils of pipes I 9 and 22 are packed in a desirable heat insulating material, such as asbestos wool, and the entire apparatus enclosed in a metallic casing I.

The inclined troughs II and I2 form a system of bafiles conveying the strong liquor over the steam pipes I and 8 contained therein and discharging over the plurality of steam pipes 9 therebelow, effects a ready distillation of the refrigerant from the solvent, and enables a more complete separation for any given still temperature making the distillation possible in a small still.

The gaseous refrigerant passing from the still through the pipe enters the bottom of the rectifier F, whereby any of the solvent which may have distilled over with the refrigerant will be condensed and drain back through said pipe to the interior of the stilll. The refrigerant in the form of a gas is conducted by a pipe through a condenser C of conventional form where it is condensed to a liquid and thence into a receiver D of conventional form and from thence through an expansion valve V of conventional form to the evaporator E, the lower side of which conveys the gaseous refrigerant through a pipe to the absorber.

What I claim is:

In a steam operated absorption refrigerating apparatus, a still therefor including a sealed horizontal cylindrical casing having an inlet for the strong liquor in the top thereof adjacent the one end and a gaseous refrigerant outlet in the opposite end, cylindrical steam chambers of less diameter than that of the casing mounted adjacent each end of the casing with the chamber adjacent the strong liquor inlet secured to the top of the casing and the opposite chamber resting on the bottom of the casing, a plurality of steam pipes connecting said chambers and said chambers connected in a. steam line, said 0011- necting pipes beingnarranged in horizontal rows extending in parallel relation to the axis of said chambers with the row next below the top row extended from the chamber opposite the strong liquor inlet at an incline therefrom to join the other chamber at its approximate horizontal center line, and troughs arranged under the top and next below rows of steam pipes extending from the steam chamber adjacent the strong liquor inlet under the top row of pipes and spaced apart from the opposite chamber with the outer trough extending from the latter chamber and terminated short of the first chamber to carry the strong liquor over the two top rows of steam pipes in the presence of the gaseous refrigerant distilled from the strong liquor in passing o'ver the steam pipes therebelow, and a weak liquor discharge provided in the bottom of the casing.

GLENN F. ZEILHOEFER.

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