US2075921A - Treatment of restricted flow tubing and apparatus therefor - Google Patents

Description

April 6, 1937. W G WlNKLER ET AL 2,075,921

TREATMENT OF RESTRICTED FLOW TUBING AND APPARATUS THEREFOR Filed Jan. 15, 1935 2 Sheets-Sheet l o Q q a N J K t s' a i m 0 q r v 4 M 1 c 3 N w a O s Q a Q 3 5 Q 5 N E 1, H

c o q fi/va BY AL BERT G. BEUCK- ATTORNEYS,

Apyiifi, 1937. w. G. WINKLER ET AL 2,075,921

TREATMENT OF RESTRICTED FLOW TUBING AND APPARATUS THEREFOR Filed Jan. 15, 1935 2 SheetsSheet 2 K Ea 3.

INVENTORS. M V/V/VE C1 WIN/(L ER Patented Apr. 6, i937 UNITED STATES PATENT OFFICE 3 TREATMENT OF RESTRICTED FLOW TUB- ING AND APPARATUS THEREFOR Wynne G. Winklenand Albert G. Bruck,-Cincinnati, Ohio,

assignors to The Crosley Radio Corporation; Cincinnati, Ohio, a corporation of Ohio Application January 15, 1935, Serial No. 1,920

I 9 Claims. (Cl. 153-2) particular exemplary, but not limiting, use therefor. In the use of restricted flow devices, such as socalled capillary tubes in domestic refrigerators, where the capillary tube is used as the means for feeding liquefied refrigerant into the evaporator of the mechanical system, the proper functioning of the apparatus depends, among other factors, upon a nice proportioning of the capacities of the variousinstrumentalities in the system. By way of example, assuming that the capillary tube always receives a supply of liquefied refrigerant from the condenser, it will be clear that the capacity of the evaporator must be such as to be capable of receiving a continuous flow of the refrigerant without marked changes of pressure in the evaporator occurring solely from such flow. The evaporator must in fact be neither too large in capacity, nor too small, and assuming that the other elements of the system are of proper kind and capacity, and function properly, the capacity of the evaporator must be quite closely proportioned to the feeding capacity of the particular restricted flow device employed. In commercial practice of course the evaporators are made up in standard units of a given size and capacity, and and control mechanism it is not practicable to modify them to make them conform to variations in the capacity of the restricted flow devices. Clearly, therefore, the restricted flow devices must be brought to a given capacity within very narrow tolerances. The

ordinary manufacturing tolerances are too wide 40 to give consistently good results. As a consequence, it has been necessary to take the tubes as manufactured and test each one of them, discarding all but those which had the correct ca pacity. This represents a wastage so far as the 45 manufacturer of tubing is concerned, and the purchaser of such tubing has had to pay a very much larger price for selected tubing than he would have had to pay for the ordinary product of the mill.

There has hitherto been no suggestion leading to a solution of this selection problem. Theoretically in a small bore tube, the function of which is to interpose substantial resistance to the passage of fluidrvariations in borecould be taken care of by variations in length. It willbe clear,

tolerances; but we shall however, that this could not be done without considerable wastage of material, since the bore varies from point to point in the tube, and since it is not possible to predict within narrow enough tolerances the average eflective bore of any given length of tubing.

It is an object of our invention to provide a means whereby standard lengths of tubing may be taken and tested, and if they are found to depart from the permissible tolerances, treated so as .to bring them within said tolerances. It is an tion and arrangement of parts, and by those certain process steps of which we shall now describe the aforesaid exemplary embodiment.

Reference is had to the drawings:- Figure 1 is a plan view of the treatment device showing in a semi-diagrammatic way the testing Fig. 2 is an elevational viewof the treatment device. V

Fig. 3 is an enlarged view of the rolling mechanism.

Fig. 4 is a sectional view taken along the lines 4, 4 of Fig. 1. Briefly, in'the practice of our invention, we control the effective internal diameter of a restricted flow tubing by slightly flattening the tubing a controlled amount, while testing the tubing to determine its capacity as so flattened. We have found it readily possible'to do this because in tubing manufactured for-refrigerator use a flattening of as much as .020 inch has been made without any impairment of the tubing, and

without any seam-cracking. This is not given as the limit of the flattening-which may be attempted, but as illustrative of the largest degree of flattening which wehave found necessary .in anyselected tubinghaving thelordinary-manufacturing tolerances. Control is had both by the degree of flattening and by the extent of along the length of the tubing.

In the practice of our invention we ordinarily set up a testing apparatus which comprises a 5 cylinder of fluid under known pressure, a restricted flow device known to be correct in capacity, together with a pressure gauge to give an indication of that capacity. We likewise set up a second pressure gauge connected to the tubing which is to be treated, andwe stretch this tubing out upon a long table. Assuming that the tests on the last mentioned tubing show too high a capacity, the tubing is then progressively flattened, as will hereinafter be descri ed, until its capacity is correct. whereupon another tube may be treated.

An exemplary apparatus is shown in the fig;

ures, where in Fig. i a tank I is maintained und r\ a known fluid pressure, say, 200 lbs. of air. A standard restricted flow tubing is indicated at 2,

connected with a pressuregauge 3. Preferably there will be between this pressure gauge and the 'tank i a restricted flow device of known capacity 5. The unconnected end of the standard capillary tube is left open, and the gauge 3 will give an indication of the back pressure produced by the restrictive effect of the'device 2.

For testing the tube to be treated, we. provide a restrictive device 6 of the same capacity as the device 5, and a gauge 1 similar to the gauge 3.

. A standard coupling is shown at 8, and the capillary tube under treatment is indicated at 9, and

is connected to this coupling. The tube 9 is stretched out upon a long table III, a marginal portion of which forms one of the co-cperating 'rolling surfaces therefor. A roll H, mounted in a traveling housing |2,,is arranged to be passed along the table. Reference to Figs. 3 and 4 will show the housing or standard member I2 mounted as, for example, by keys I: operating in keyways along the edge of member I2 can slide therealong. The motion of the member I2 is controlled bya pinion H attached to a shaft l5 passing through the standard I2. The pinion l4 meshes with the teeth of a rack IS in a cut-out portion I! of the table edge. A crank I8 is attached to the shaft 15 so that it may be rotated.

The standard member I! has a cut out portion 50' IS, the sides of which form guides for the sliding -movement of a bearing member 20. The roll .ll

may be mounted on a shaft 2i, journaled in the bearing member 20, and a screw-down device is indicated at 22, preferably having a micrometer adjustment dial 23, operating in conjunction with a pointer member 24 to indicate its position. It will .be clear that the pressure of the roller ll against the tube- 9. can be varied by means of the screw-down 22, and the flattening effect gauged by means of the micrometer fl. It will further beclearthat the whole flattening fixture may be moved longitudinally of the table edge by meansof the crank l8. In many instancesgit will not be necessary to flatten a tube throughout its entire length; inother instances it may be necessary to roll the tube more than once in order to secure the desired total flattening effect. In any event, however, itis our practice to flatten a tubing in such a way that a few inches of unflattened tubing are left at either end, of the restricted flow device so that the ordinary connections may be made thereto when the tube is placed in a refrigerator for use.

When proceeding empirically to flatten a tube, 75 and using the set-up shown in Figure 1, let it be it, as measured the table, so that the Modifications may be without departing from supposed that the gauge I shows less back pressure than the gauge 3, indicating that the bore of the tube 9 is too large. We start with the flattening fixture on the standard I! at the left hand end of the table, and adjusting the screwdown of the roll ll so as to flatten the tube slightly, we rotate the handle is so as to cause the flattening flxture to travel toward the right hand end of the table, thus-progressively flattening the tube. During the traveling of the flattening fixture, we observe the gauge I, and as soon as this gauge reads the same as the gauge 3, we stop the motion of the flattening fixture and remove the-tubing 9, which has now been finished. -If the desired back pressure is not attained during the entire transit of the flattening fixture, we tighten the screw-down again and iii cause the flattening fixture again to traverse the iength of the tube, repeating this operation as many times as may be desired to secure the necessary effect.

With some experience in the treatment of tubing in accordance with our invention, it will not usually be necessary to proceed empirically. With tubing made to ordinary manufacturing tolerances, a given back pressure will usually indicate a. treatment for a given length of the tubing with a given and predetermined screwdown. This is the reason why we have provided the micrometer setting for the roll, and it will likewise be competent to mark of! the table In with a scale in inches, or other convenient units of length, to indicate the travel of the flattening fixture. when this is done, the tubing may be treated very rapidly to bring it nearly to the required restriction, andthe gauges 3 and 1 observed only durlng the final stages of the treat- I ment.

By the use of this apparatus and process, we have foundit possible not only to purchase unselected tubing on a more economical basis. but to bring all of our tubing to an accurate standard, which is much more nearly exact than it was possible to attain even with selected tubing in commercial operation.

made in our invention the spirit thereof. Having thus described our invention, what we claim as new and desire to secure by letters Patent, is:

1. A method of treating restricted flow tubinl of over capacity, which comprises connecting. a desired length of said tubing to a source of fluid pressure and restricting the bore thereof to bring it to the required capacity by flattening ssid tubing.

2. 'A method of treating restricted flow tubing of over capacity, which comprises connecting a desired length of said tubing to a source of fluid pressure and restricting the bore thereof to. bring it to the required, capacity by flattening said tubing by progressively rolling said tube in the direction of its length. V

3. A methodof treating restricted flow tubin of over capacity, which comprises connecting a desired length of said tubing to a source of fluid pressure and restricting the ,bore thereof to bring it tothe required capacity by flattening said tubing by progressively rolling'said tube in the direction of its length, whileleaving an unrolled portion thereof at each-end.

4. A method of treating restr cted flow tubing of over capacity which comprises connecting a desired length of said tubing to a source of fluid pressure, and progressively rolling said 7 tubing so as to flatten it, ceasing .said rolling when said tube shows the desired restrictive effeet.

5. A method of treating over capacity, restricted flow tubing, which comprises arranging a comparative test of a known sample of tubing, placing the tubing to be treated under test by connecting it to a source of fluid pressure, and progressively flattening the tubing under test until it shows the same value as the known sample.

6. In a device for treating capillary tubing, 9. table of a length comparable to the desired length of tubing, a standard member arranged for longitudinal travel along the table edge, a roll rotatably mounted in said standard member and having a movement toward and away from said table top, and means for adjusting the position of said roll with reference to said table top, said means comprising an indicating micrometer adjustment.

7. In a device for treating capillary tubing, 2. table of a length comparable to the desired length of tubing, a standard member arranged for longitudinal travel along the table edge, a roll rotatably mounted in said standard member and having a movement toward and'away from said table top, means for adjusting the position of said roll with reference to said table top, said means comprising an indicating micrometer adjustment, means for moving said standard along said table edge, said means comprising a rack in association with said table edge and a pinion in association with said standard, and means for rotating said pinion.

8. In a device for the purpose described, a source of fluid pressure, a standard restricted flow device connected therewith, a gauge for indicating the eflective capacity of said standard restricted flow device, a restricted flow device to be treated, means for connecting said last mentioned restricted flow device to said source of fluid pressure, a gauge to indicate the eifective capacity thereof, and means for treating said last mentioned restricted flow device to vary its eifective capacity.

9. In a device for the purpose described, a source of fluid pressure, a standard restricted flow device connected therewith, a gauge for indicating the effective capacity of said standard restricted flow device, a restricted fiow device to be treated, means for connecting said last mentioned restricted flow device to said source of fluid pressure, a gauge to indicate the effective capacity thereof, means for treating said last mentioned restrict-ed flow device to vary its effective capacity, said means comprising a rollin'g mechanism, and means for causing said mechanism to flatten said tube progressively in the direction of its length.

WYNNE G. WINKLER. ALBERT G" BRUCK.

Images