US2510952A - Temperature testing chamber - Google Patents

Description

June 13, 1950 1 A BREWSTER 2,510,952

TEMPERATURE TESTING CHAMBER Filed June 30, 1944 if F`IG.3

o INVENTOR. LESLIE ABREWSTUQ ATTO/@Nif tions.

Patented June 13, 1950 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 3i), 1928; 370 0. G. 757) 3` Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The invention to be hereinafter described relates to air mixer for heat testing cabinets.

It has long been common practice to test the effects of varying degrees of temperature or heat upon given material, manufactured articles, equipment, etc. For this purpose, heat testing cabinets have been devised of various construc- Frequently the cabinet comprises several intercommunicating compartments or chambers, a circulating device for causing air flow through such compartments and a control device for pron portioning or otherwise regulating the air flow through the compartments. Some such cabinets also include an air heater and an automatic regulator for the heater. Many of these cabinets, as heretofore constructed, are unnecessarily complicated, correspondingly eXpensive and proportionately inefficient. Many of them flow a current of warm air directly on the coolant to lower the air temperature. The result of that is a great waste of the coolant and too sudden drop in the temperature of the heated air, making regulation difficult. Also sudden variations in temperature may be damaging to the materials being tested. Such sudden changes are very likely to be damaging to the test cabinets. Even when there is not that damaging effect to the materials being tested, the relatively sudden changes in temperature resulting make control difficult and may cause uncertain, inaccurate and unreliable calculations and determinations so that the tests are of less value than they should be.

'Ihe present invention avoids the above and other objections and provides a simple, enicient, compact and low cost testing cabinet of few parts in which the air flow control is simple and eilicient and no hot air current is permitted directly over and across the coolant.

In order to more clearly disclose the construction, operation and use of the invention reference should be had to the accompanying drawings forming part of the present application.

Throughout the several figures of the drawings like reference characters designate the same parts in the different views.

In the drawings;

Fig. 1 is a front view of the cabinet, closed;

Fig. 2 is a horizontal cross section on line 2-2 of Fig. 3; and

Fig. 3 is a central vertical cross section.

A preferred construction comprises a box like cabinet body i adequately heat insulated relatively to the uses to which it is to be put. This body is divided into three intercommunicating chambers 2, 3 and 4 respectively.

Chamber 2 is the cold chamber in which is placed a coolant such as Dry Ice. Any other suitable coolant, refrigerant or refrigerating device Inay be used, adequate for the purposes for which the cabinet is to be used. Any such material or device should be, and logically is, disposed in the upper part of the chamber, a shelf, bracket or similar support 5 on one wall of the chamber providing a seat in extension of the top wall of the hot air chamber 3. In this arrangement, the Dry Ice or other cooling agent bridges the space between 5 and. the top of the horizontal branch or" 3. Preferably a heavy screen, grid, or other open-work plate or like device not here shown or further described, bridges the space mmediately below the cooling means and acts as additional support. This is particularly desirable where ice or Dry Ice is used. As such coolants decrease in size they would eventually, drop through between 5 and the end of chamber 3 into the lower part of chamber 2 where they would be of least eiliciency. Such a grid is, therefore, desirable .but not an essential part of this application.

In the lower part of chamber 2 below the refrigerant or cooling means and `below the hot air chamber 3 is journaled a fan extending into an opening in the lower part of wall 'i which separates chambers 2 and 4.

The hot air chamber 3 between chambers 2 and A, in the preferred form of the invention, is substantially L-shaped in vertical cross section, the lower outer end of the L opening into the upper part of the lower portion of the cold chamber 2 directly beneath the support for the cooling or reirigerating means. This chamber 3 comprises the two parallel, spaced, L-shaped partition walls 3 and 9 extending from front to rear of the cabinet, those cabinet wall portions between 8 and 5i completing that chamber. Or, of course, charnber 3 may be made as a complete unit with end walls and insertable as one piece. Walls 8 and 9 are provided with circulation openings l@ and I l, respectively, for the low of test chamber air from chamber1 4 simultaneously into 3 and 2, exclusively into 2 or exclusively into 3, according to circumstances and as desired. Openings IG and H, preferably, extend the full length of walls 8 and 9, from front to rear of the cabinet. However, such openings may or may not be continuous throughout their lengths as may be individilally desired. In the cabinets so far actually constructed, they are continuous. As shown, in the preferred construction, openings lil and li are aligned. Between openings le and il, in 3, is journaled, either in the end walls of S or in the walls of the cabinet, a cylindrical valve i2 so proportioned that it may completely close either opening lll or il or the upper portion of chamber 3.

The normal position or" l2 is as shown in the cross sectional view. In that position, air circulated by fan 5 through chamber 'li passes through opening lil in wall 'e and into chamber 3. Due to the position oi valve i2, part oi the flow will pass downwardly in chamber '-3 and the remainder will pass into the upper part o the cold chamber 2 above, and down over the dry ice or other coolant or rerigerating medium or device, and thence into the lower part o chamber .2 for-recirculation by fan 6. And, as will be clear, `the air passing down in chamber 3 will also flow into the lower part of chamber 2, the two flows mixing as they are fed for-ward by fan 6 into chamber e.

Within chamber r3 and in the downward path cfiow therethrough is a suitable resistance heaterA i3 of well known type.

Within chamber d is a well known type oi standard thermostatic heat control device hi. It

is -iconnected in usual and well Known manner in 'thecircuit oi heater i3 to automatically turn on or orf the heating current. These devices and their connections and interconnections are all well :known to those skilled in the art and need no further illustration or description here.

The axis or shaft I5 of vaive l2 is extended through the front wall of the cabinet and provided with a pointer or other device it cooperating with -a suitable dial plate il. Valve l2, in originally assembiing the cabinet, is so Set that its vrelative control positions will be indicated on the dial by the pointer, the pointer also constituting -a handle for manipulating the valve. For instance, in the present construction, the dial could readily show cold, hot, intermediate and closed.

And, of course, it may be readily graduated to indicate fractional or small movements in one Vdirection or the other. In that arrangement, cold could indicate that valve l2 would be set to direct either all air now through l and l l and the cold chamber 2 and none through heating chamber 3 or :agconsiderably greater part through it and l l :and 2 than through 3. In the same arrangement, hot could indicate, similarly, a position of valve i2 directing all or most of the flow through chamber 3. In like manner, intermediate could Vindicate a valve positionY directing approximately equal portions yof the air from chamber i through t and 2. This position is illustrated in Fig. 3. Finally, closed could indicate a valve position completely closing mand cutting off 'chamber il `from 2 and 3, permitting opening of chamber 2 for renewing refrigerant or replacing, repairing, etc. the rer-igerating device. In that case, the temperature in the testing chamber d will not be appreciably affected during opening oi cham- Y vber 2.

`Manipulate valve l2 until the thermostat I4 shows the temperature in s being maintained constant. When that point is reached, place in the test chamber the material or article to be tested and leave it the predetermined period of the test.

The themostat and valve, as set, will maintain the temperature constant.

By this construction-and arrangement hot air from chamber 3 never iiows directly onto the coolant or refrigerator or through the cold chamber 2. The only air that ows into that chamber is from the test chamber which is considerably lower in temperature.

By this construction and arrangement neither the hot air from chamber 3 nor the cold air from chamber 2 goes directly into the test chamber Instead both are intimately mixed by fan 6 .and delivered as a mixture with temperature intermediate between that or the two and approximately that of the test chamber. This gives a far more uniform condition in chamber d and avoids possible sharp drops or yrises in temperature in that chamber.

it is thought that the construction, operation use of the invention will be clear from the preceding detailed description.

Many changes may be made in the construction, arrangement and disposition of the various parts of the invention and in the materials used therein, within the scope of the appended claims without in any way departing from the field of the invention and it is meant yto include allsuch within this application wherein only one preferred iorm has been disclosed by way of illustration and with no thought or intention to, in any regree, limit the invention thereby.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. A testing cabinet comprising, in combination, a testing chamber', a cooling chamber, a heating chamber extending from the -front through to the rear oi said cabinet between said testing and cooling chambers, said heating chamber being provided with aligned openings for the flow oi air from said testing chamber into said 'heating chamber and across said heating chamber into said cooling chamber, means for circulating air from said heating and cooling chambers into said testing chamber, and .unitary valve means having a plurality of positions for regulating said air flow from said testing `chamber, said valve means being selectively and fprogressiveiy variable from a first position in which all the air flowing from said testing chamber is cut-ofi, to a second position in which all the air hows from said testing chamber. intosaid cooling chamber, to a third positionl'in which all ithe air ows from said testing chamber linto said heating chamber, said vaive means bei-ng variably positionable between the aforementioned positions for proportioning the nowoi Eair 'from said testing chamber within the limits set by the aforesaid positions.

2. A testing cabinet comprisinggin combination, a testing chamber, a cooling chamber, Va heating chambereXtendi-ng from the front throught@ the rear oi said cabinet between said `testingfand cooling chambers, -said heating 'chamber Kbeing provided with aligned openings i'o'r the flow/of air from said testing chamber into Asaid Vheating chamber and across saidY heating :chamber into said cooling chamber, said heating v chamber opening into the ylower portionv of said cooling chamber, said testing chamber having-an opening `for receiving the combined output of said heating and cooling chambers, means positioned in said testing chamber opening for circulating the air from said heating and cooling chambers into said testing chamber, and unitary valve means having a plurality of positions for regulating the air ilow from said testing chamber. said valve means being selectively and progressively variable from a first position in which all the air flowing from said testing chamber is cutoff, to a second position in which all the air flows from said testing chamber into said cooling chamber, to a third position in which all the air iiows from said testing chamber into said heating chamber, said valve means being variably positionable between the aforesaid positions for proportioning the flow of yair from said testing chamber Within the limits set by the aforesaid positions.

3. A testing cabinet comprising, in combination, a testing chamber, a cooling chamber, a heating chamber extending from the front through to the rear of said cabinet between said testing and cooling chambers, said heating chamber being provided with aligned openings for the 110W of air from said testing chamber into said heating chamber and across said heating chamber into said cooling chamber, said testing chamber having an opening for receiving the combined output of said heating and cooling chambers, means positioned in said testing chamber opening for circulating the air from said heating and cooling chambers into said testing chamber, means Within said cooling chamber positioned above the opening into said testing chamber for supporting a cooling medium, and unitary valve means having a plurality of positions for regulating the air flow from said testing chamber, said valve means being selectively and progressively variable from a first position in which all the air owing from said testing chamber is cut-off, to a second position in which all the air flows from said testing chamber into said cooling chamber, to a third position in which all the air flows from said testing chamber into said heating chamber, said Valve means being variably positionable between the aforesaid positions for proportioning the ilow of air from said testing chamber Within the limits set by the aforesaid positions.

LESLIE A. BREWSTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,609,964 Roby Dec. 7, 1926 1,859,613 Bailey May 24, 1932 1,904,697 Ruppert Apr. 18, 1933 2,254,185 Newton Aug. 26, 1941 2,234,764 Parks June 2, 1942 2,359,796' Russell Oct. 10, 1944 2,373,333 St, Onge Apr. 10, 1945

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