US 2579053 A
Description (OCR text may contain errors)
Dec, 18, 1951 H, H. scHULsTADT DEHYDRATOR 2 SHEETS-SHEET l Filed May 15, 1946 WITNESS ATTORNEY Dea 18, 1951 H. H. scHLJLsTADT 2,579,053
DEHYDATOR Filed May l5, 1946 2 SHEETS-SHEET 2 WITNE'StS` 2 Patented Dec. 18, 1951 DEHYDRATOR Herbert H. schulstat, Middletown. N. J.
Application May 15, 1946, Serial No. 669,919
rlhis invention relates to refrigeration systems and particularly to a system in which the refrigerant fluid employed is of the organic type, such for instance as methyl chloride, methylene chloride, or the commercially well-known Freon c l2 or Freon 22.
Two of the characteristics of the organic refrigerants above mentioned are that none of them is miscible with water and each is heavier than water, and consequently the latter floats on the refrigerant when it is in its liquid form. These characteristics are, from a certain viewpoint, disadvantageous when moisture is present in the lines of a mechanical refrigeration system charged with one of these organic refrigerants. This arises from the fact that the moisture, which collects on top of the refrigerant in the storage tank of the systemy as a result of the difference in specic gravities, tends to freeze on the usual expansion valve should the system spring an undetected leak and the water be siphoned out .of the storage tank and transmitted through the system to the expansion valve. To prevent this, it is customary to include in the system between the refrigerant storage tank and the expansion valve a de hydrator which is charged with a drying agent of a deliquescent nature, such for example as silica gel. 'I'he primary purpose of this dehydrator is to absorb the moisture in the refrigerant before the latter reaches the expansion Valve.
The dehydrators now in use are very eifective as long as the drying agent contained therein is not exhausted. When the drying agent is saturated the dehydrator no longer serves any useful purpose until such time as the exhausted lagent is replaced with a fresh charge. One of the short-comings of the dehydrators now in general use is that no means is incorporated therein which will indicate when the drying agent is exhausted. Without such indication, it is diflicult to know exactly when to replace the charge.
Therefore, it is the primary object of the present invention to provide an improved refrigeration system having contained therein means for indicating the presence of moisture in the refrigerant.
Another object of the present invention is to provide a refrigeration system dehydrator which not only indicates the presence of moisture in the refrigerant but also indicates when the drying agent contained in the dehydrator is approaching exhaustion.
2 Claims. (Cl. B10-131) A -further object of the invention is to provide `a refrigeration system dehydrator having visible means indicating the presence of moisture in an organic refrigerant `and `also the exhaustion of the charge of drying agent in said dehydrator.
Gtherobiects-of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:
Fig. l is a vertical longitudinal sectional view of a preferred embodiment of the present invention.
Fig. "2 is an elevational view of the dehydrator shown in Fig. l, with --some of the drying agent at the bottom of the device having absorbed moisture and consequently changed color, there by indicating not only the presence of moisture in the system but also the amount of drying agent not yet exhausted.
Fig. 3 is a bottom plan View of the outlet conduit, Vshowing the manner in which the moisture deecting ns are attached thereto.
Fig. 4 is a View similar to Fig. l, but showing a modication of the device.
Fig. 5 is a diagrammatic view of a refrigeration system having incorporated in it my improvement.
Referring now more particularly to Fig. 5, I have shown a refrigeration system including a cooling tank or evaporator I housing an expansion `coil II connected at its delivery end by a conduit I2 to the intake side of a conventional compressor I3. The outlet side of the compres' sor I3 is connected by a conduit I4 to a condenser I5 cooled by means of a motor-driven fan IB. The condenser is connected by a conduit `Il to a refrigerant storage vor receiver tank i8. Refrigerant in the storage tank I3 is delivered through the conduit I9 and shut-01T valve 20 to an expansion valve 2! located at the receiving end of the expansion coil I I. Connected in `the line I9 between the storage tank I and the expansion valve 2| is my improved indicating dehydrator identiiied generally as 22. The system shown in Fig. 5, with the exception of the indicating dehydrator 22, is conventional and operates in the usual Well-known manner, Suflice herein to say that the refrigerant upon `leaving the expansion coil I I through the conduit I2 is in a gaseous state at low pressure. The compressor I3 increases the pressure of the gas, after which the condenser I5 cools the high pressure gas which is then delivered to the storage tank `I8 in liquid form. From the storage tank the liquid refrigerant is delivered by the conduit I9 to the expansion valve 2l where the pressure of the liquid refrigerant is reduced, converting the refrigerant into a low pressure liquid .or gas. During the operation of the system the above described cycle is of course continuous.
In practice the refrigerating systems sometimes spring a small undetected leak through which the refrigerant is gradually lost. It will be appreciated that small leaks do occur in the system owing to the fact that the organic refrigerants are strongly solvent and that the leaks may be undetected because the organic refrigerants most widely employed today are odorless. When the level of the refrigerant in the storage tank drops, as a result of the leak, any moisture which may be floating on top of the refrigerant in the storage tank is lowered to a level where it is siphoned into the system.- Unless removed from the system, this moisture is led to the expansion valve 2| where, as a result of the functioning of the valve, the temperature is dropped to a point where the moisture freezes in the expansion valve and interferes with its proper operation. In fact, in new installations where moisture is invariably present, this condition frequently causes a complete breakdown. In an effort to eliminate this defect, it has become common practice to connect, in the line between the storage tank and the expansion valve, a dehydrator the function of which is to remove the moisture from the refrigerant as the latter travels through the dehydrator. The commercial dehydrators now on the market are successful in removing the moisture from the refrigerant as long as the drying agent in the dehydrator has not been subjected to sufficient moisture to exhaust the drying agent of its absorption powers. If thisrshould occur, the dehydrator is useless until the charge of drying agent can be replaced. It is the purpose of the present invention to provide a dehydrator which is designed to indicate when its charge of drying agent is exhausted. In its preferred form, my improved dehydrator indicates when moisture is present in the system and also indicates the progressive exhaustion of the drying agent, thereby giving ample warning before the charge of drying agent is completely exhausted so that it can be replaced at the proper time. Referring to Fig. 1, I have shown a preferred embodiment of my dehydrator comprising a casing including a metallic bottom end-cap 23, a metallic top end-cap 24 and a tubular Vbodymember 25 of transparent material, preferablyl Pyrex glass, interposed between and suitably secured to said end-caps 23 and 2 4. The endcap 23 is provided with a threaded inlet duct or bore 26 into the lower end of which is threaded a conventional pipe-fitting 21 on the conduit I9. The top end-cap 24 has a threaded outlet duet or bore 28 into which is threaded a pipe-fitting 29 on the conduit I9. Removably threaded in the inlet bore 26 of the bottom end-cap 23 is a screw-plug 30 having a central hole 3| and a reduced liange 32. Soldered or otherwise secured to the flange 32 is a vertically disposed tubular inlet screen 33 closed at its upper end. To provide for removing the screen 33 to permit a re-` charging of the drying agent, the screw-plug 30 is formed with a screw-driver slot 34 which is rendered accessible by removing the pipe-fitting 21.
Threaded in the outlet bore 28 of the top endcap 24 is a screw-plug 35 with a central opening in which is soldered or otherwise fastened the upper end of an outlet tube 36 depending within the tubular body 25. At its lower open end the 4 tube 36 has secured to it sheet-metal fins 31 the function of which will be later described. To provide for the removal of the tube 36, the screwplug 35 is preferably formed with a screw-driver slot 38.
Disposed within the transparent Pyrex body 25 is a charge of drying agent 39 which, according to the present invention, has capacity for changing color upon the absorption of moisture. A drying agent which I have found to be entirely satisfactory is silica gel treated with cobalt chloride which imparts to the silica gel a blue color. When the blue silica gel comes into contact with moisture, it changes color from its characteristic blue to a pink. With the above in mind, it will -be obvious that, in the event moisture is present in the refrigerant as it passes up through the dehydrator, the blue silica gel within the transparent tubular body 25 will not only absorb the moisture, but in doing so will also change color from a blue to a pink. This change ofcolor of the silica gel is visible through the transparent body 25. Therefore by merely looking at the dehydrator the observer is aware that moisture is present in the system. Also, the percentage of the charge still available can be readily seen. Fig. 2 shows the dehydrator in front elevation with the lower portion of the drying agent charge exhausted and consequently pink in color, while the upper portion thereof is still effective and therefore blue in color.
Referring to Fig. 1, it will be seen that on top of the drying agent 39 there is located a filter preferably having the form of two spaced disks of line mesh wire screen 49 and 4I between which there is disposed a hair felt pad 42. The filter serves to prevent small dislodged particles of the dehydrating agent 39, which undergoes more or less continuous movement while the dehydrant is in effective operation, from being transmitted into the system. It will -be evident that the filter pad is spaced from beneath the top end-cap 24 to provide a cavity 43 which, during'the normal operation of the system, is lled with the refrigerant. The refrigerant, in traveling from the cavity 43 through the outlet bore 28 of the end-cap 24, must enter through the lower open end of the tube 36. In the event moisture gets past the dehydrant 39, it will rise to the top of and float on the refrigerant at a level above that of the lower end of the tube 36. In other words, that portion of the cavity 43 above the level of the lower end of the tube 36 forms, in effect, a trap for collecting any' moisture which may escape the drying agent 39. To preclude the moisture which escapes the drying agent 39 from entering directly into the open end of the tube 36 as it is rising to the top of the refrigerant, there are provided the iins 31 which, function as guide means for directing the beads of moisture out of range of the lower open end of the tube 36.
Fig, 4 represents a modification of the dehydrator shown in Figs l to 3, inclusive. In the modiiication, the casing includes a bottom end-cap 44, an upper or top end-cap 45 and a transparent tubular body-member 46, preferably of Pyrex glass. The two end-caps and the tubular body are maintained in assembled relation by means of a centrally disposed assembly-rod 41 threaded at its upper end into the end-cap 45 and at its lower end slidably fitted in a central bore 48 formed in the lower end-cap 44. The projecting portion of the lower end of the assembly-rod 41 is threaded, as at 49, to receive the square or hexagonal locking-nut 59, which when tightened effectively clamps the tubular body 46 between the two end-caps 44 and 45, and which provides means for disassembling the dehydrator to replace the dehydrant charge. In order to prevent leakage between the tubular body 46 and the endcap 44 and 45, the two end-caps are each formed with a circular channel i into which projects the end of the tubular body 46, there being interposed between the end of the tubular body and the bottom of the channel 5I a resilient ringgasket 52. To preclude leakage along the bore 48 between the end-cap 44 and the assembly-rod 41, there is provided a resilient ring-gasketv 53 which is placed under pressure by the lockingnut 50 when the latter is tightened to maintain the unit in assembled relation.
To provide an inlet for the refrigerant, the assembly-rod 41 is longitudinally bored at its lower end to form a duct 54 which is intersected adjacent its upper end by the four radial ports 55. Surrounding the assembly-rod 41 immediately above the lower end-cap 44 is a lter comprising spaced disks of ne mesh bronze-wire 56 and 51 having interposed between them a pad 58 preferably of bronze wool. Resting on the lter is the charge of drying agent 60 which, like the drying agent 39 in the preferred embodiment of the device, has the capacity of changing color as it becomes saturated with water. Disposed on the top of the charge of drying agent is a second lter comprising two spaced disks of ne mesh bronze- Wire 6| and 62 between which is a pad 63, preferably of hair felt. After passing up through the dehydrant 60 and the top lter, the refrigerant is delivered through the radial ports 64 into a central duct 65 in the upper portion of the assemblyv;-
rod 41. It will be seen that the radial ports 64 are spaced down from the end-cap 45 for the purpose of providing a closed cavity above the ports 64 to trap any moisture which may escape the dehydrant 50.
From the above description, it will be understood that I have provided a refrigeration system having means for indicating the presence of moisture in said system. Not only is the presence of moisture indicated immediately as it travels through the system, but it is absorbed before it can do any damage. Also, the period of eifectiveness of the dehydrator readily can be observed, with the result that maximum life can be obtained from the dehydrator without fear of using the same beyond the effective life of its charge. While I have shown the tubular body of the dehydrator as being made of transparent glass, it will be understood that the same may be made of metal or the like tted with a judicially arranged transparent sight through which the change of color of the drying agent may be visible. Also, while I desire to use a drying agent which changes color upon contact with water, the invention in its broadest aspect may be considered to cover an agent which changes its shape or size or form upon contact with water, as long as such change in character may be discernible through the transparent portion of the body of the device.
Having thus set forth the nature of the invention, what I claim herein is:
1. A dehydrator adapted for use in abstracting water from the medium of a refrigeration system, comprising a body-member having an inlet at its lower end, a top end-cap secured to said body-member, a charge of drying agent contained in said body-member and spaced `below said top end-cap, an outlet tube secured to said top endcap and depending within said body-member with its lower open end spaced below said top endcap and terminating above said drying agent to provide a cavity above the lower open end of the tube for trapping any water which may escape past said drying agent, and a bale device disposed at the lower open end of said outlet tube to deflect water out of range of said lopen end should any water escape through said drying agent.
2. A dehydrator adapted for use in abstracting water from the medium of a refrigeration system, comprising a body-member having an inlet at its lower end, a top end-cap secured to said bodymember, a charge of drying agent contained in said body-member and spaced below said top endcap, an outlet tube secured to said top end-cap and depending within said body-member with its lower open end spaced below said top end-cap and above the top of said drying agent charge to provide a cavity above the lower open end of the tube for trapping any water which may escape past said drying agent. and a baille in the form of plate-like iins having inclined edges disposed at the lower open end of said outlet tube to lead the beads of water away from the open end of said tube should any water escape through said drying agent.
HERBERT H. SCHULSTADT.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 650,149 Howard May 22, 1900 1,281,064 Pfanstiehl Oct, 8, 1918 1,601,308 Hill Sept. 28, 1928 1,914,829 Imhoff et al June 20, 1933 1,917,121 Hughson July 4, 1933 2,199,258 Gray Apr. 30, 1940 2,210,862 Tronstad Aug. 6, 1940 2,232,025 Glisan Feb- 18, 1941 2,243,949 Fox June 3, 1941 2,260,608 Cormack Oct. 28, 1941 2,323,160 Stecher et al June 29, 1943 2,325,657 Burkness Aug. 3, 1943 FOREIGN PATENTS Number Country Date 437,139 Great Britain Oct. 24, 1935 784,957 France July 30, 1935