Dec. 17, 1946. ' A. D. SWENSEN 2,412,638 RUBBER SEALAGING TESTINQAPPARATUS AND METHOD Filed Jan. 8,, 1945 2 Sheets-Sheet 1 ' c(owupa; l k ALBERT D4 SWENSEN _ Dec. 17, 1946. 2,412,638 A. o. SWENSEN RUBBER SEALAGING TESTING APPARATUS AND METHOD Filed Jan. 8, 1945 2 Sheets-Sheet 2 ouliso RC2: n, N 1711/ )I'I/IIIII/l A .M ,0 “mm. //:1’:w. . / [WV/.16 m,,, I W .I 3w...” m. A” . “u... MWIH"2hm:s53) IIIIIIIIII/I \ _ INVENTOR. ALBERT D. SWENSEN BY E ‘M 3 ATTORNEY 2,412,638 Patented Dec. 17,1946 umrso STATES'VP'ATENT oral-ca ‘ Albert D. Swensen, Washington, D. 0. Application January a, 1945, Serial No. 571,893 2 Claims. (01. 13-731) _ ' (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 1 . , My invention relates to testing apparatus and a method for testing sealing or gasket material ' under service-simulating conditions. In many naval and marine applications a variety of materials such as various natural and synthetic rubbers, are used as gasket materials to line hatches, doors and other openings into compartments, which it is necessary to keep in an air tight or water tight condition. To insure 2 ‘ - and the scope of the invention will be indicated \in the claims.- ' ' - For a better understanding of the nature, ob jects and scope of my invention, reference should be had to the drawings accompanying this speci? cation and the following specification in which the structure and method of using the apparatus are set forth in detail. Referring to the drawings, Figure -1 is a5 perspective view, partially in greatest safety the performance characteristics 10 section, of one embodiment of the gasket ma terial testing apparatus of my invention; of the gasket materials should be known, for it Figure 2 is a perspective view of a second .em ~is Just as inconvenient to test the gaskets after , bodiment of my invention; they have, been put in place as it is to replace Figure 3 is a sectional view of the embodiment I them frequently in order to insure maintenance of the water tight or‘ air tight integrity of the com 15 of the apparatus shown ‘in Figure 2 and taken vertically through the apparatus shown in~Fig partment. Common plasticity and stability tests ure 2; , are unsatisfactory either because they are too Figure 4 is a drawing showing the method of time consuming or because they fail to test for using my apparatus to test gasket materials for the essential properties required of good gasket 20 their sealing properties. materials. Referring to Figure 1, l0 represents a base A good gasket material is critically sensitive held to a‘support II by means of a screw l2. essentially to. at least two factors, namely, its Thirteen (I3) is a calibrated scale, the exact hardness or resistance to deformation and its nature and function of which will be explained sensitivity to aging. A good gasket material should possess moderate hardness or should yield 25 hereinafter, held to support I l by means of screws ll‘; base In is recessed to receive therein a speci underpressure in order to permit some compres- . men holder comprising cylindrical wall is and sion of the material by the faces between which base it. it is to act as a seal. It should be very resistant The wall i5 of the specimen holder has near to oxidation or deterioration with age, particu 30 its upper edge an inwardly projecting lip ll. larly in view of the applications intended; Centrally over the specimen holder there is a‘ _ It is the primary object of my invention to threaded hole in the top member it, which hole provide apparatus and a service simulating vtest is adapted to receive threaded member a 8. Mem ing method by means of which the sealing quality ber i8 is tubular in form and at its lower end is of a good gasket material andv its susceptibility to deterioration with age can be quickly and 35 rounded off‘ to form a ball indentor i5. Mem accurately determined. . It is a secondobject of my invention to pl‘0= vide simple, inexpensive apparatus so that the test or tests can be carried out quickly on a num ber is also carries an indicator 2b and a lock nut ii. ‘The upper end of the tubular member .IB‘ is adapted to receive or be coupled to a com pressed air or fluid supply. Since such connec 40 tions can be of a variety of forms no speci?c one ' ber of the specimens. has been shown in this figure. It is a third object of my invention to provide In Figure 2 I have shown a second embodiment apparatus which will test gasket materials ac .of my invention, which possesses elements of the . curately and specifically for the essential prop embodiment shown in Figure ‘1. In Figure 2 erties required of good gasket material. Further objects and advantages of my inven 45 twenty-two (22) represents a base member hav ing thereon a male threaded member 23, and also tion will in part be obvious and in part appear carrying, at any convenient point on the cir cumference of said member 23, an index line Accordingly my invention comprises the gasket 245. A canopy 25 is internally threaded. and material testing apparatus and method which apparatus involves the features of construction, 50 adapted to fit onto the threaded member 23. Around the lower circumference of canopy 25 combinations of elements, and arrangement of there is a scale 28, which is the equivalent of the parts, which will be exempli?ed in the construc hereinafter. ' ‘ ~ tion hereinafter set forth, and the method il scale carried by member 53, shown in Figure 1, The canopy member 25 is adapted to fit overla said steps to one another as will be described, 55 specimen holder 21, in substantially the ,same vclving the separate steps and relationship of 2,412,888 - manner in which the support l-l ?tted over the specimen holder in Figure 1. The specimen holder it is contemplated to use in both embodi ments is the same. The upper end of the canopy is adapted to pass a tubular member 28, which has provisions for being connected to a ?uid or compressed air‘supply, as is indicated roughly. 4 inch. Accordingly, in Figure 1 each scale divi sion therefore represents 0.001 inch. This thread pitch is an arbitrary matter and can be varied to suit the convenience of the operator. Having indented the specimen the desired amount, tubu lar member is is locked in place by means of the lock nut 2!. Connection is then made to a compressed air supply by coupling member l8 to a in the figure. The member 28 can be locked line through a reducing valve arrangement as in any position by lock screw 29. Figure 3 is a longitudinal sectional view of the 10 indicated in Figure 3. For the purpose of de tecting leakage when it starts following the ap embodiment of the apparatus shown in Figure 2 and includes a showing of a sample 21a in place plication of air pressure thereto, enough water or other liquid is added to the specimen container for test. . The apparatus of Figures 1 and 2 can be modi . i5—-l 6 to submerge the specimen surface and the ' ?ed in various details as the two modi?cations 15 nozzle is indenting it in order that leakage of the seal formed by the indentation of the nozzle _shown indicate. Essentially it is necessary to will be revealed by escape of air through the provide for causing member l8 to indent a ma liquid. The pressure at which airbubbles are terial a given amount. ‘In a third form of the apparatus member 18 was keyed to prevent its seen to escape through the surface of the water rotation and its vertical movement accomplished 20 in the specimen holder is the point at which by. means of a drive nut like lock nut ,2l of the sealing material will begin to leak and is Figure l. _ designated the unaged sealing pressure. ' In Figure 4, I have shown the apparatus in Determination of the aged sealing pressure is place as it is used in testing the sealing quality readily made in accelerated form by disconnecting of a gasket material. In this figure the parts of 25 the unit from the compressed air supply, placing the apparatus shown in detail in Figure 1 have it in an oven and maintaining it in the oven at an elevated temperature for a period Of about 48 A compressed air line 80 is attached to the open end hours and then removing and repeating the test. of member [8, which was shown in Figure 1, A different value of the pressure at which leakand in the line there is pressure gage 3i, petcock 30 age occur will be found after aging the material. 32, and reducing valve 33. Connections to an The diiIerence between the unaged and the aged oxygen or air supply are made through line 38, sealing pressure is a good quantitative indication - been indicated and are readily identifiable. and are not shown inasmuch as they are conven tional. Having now described in some detail the struc of the sealing quality of the material tested. The method of performing the sealing tests on 35 gasket materials using the apparatus described ture of my testing unit and also having shown in Figure 2 is substantially identical with that described in conjunction with the apparatus ‘ scribe the exact method of carrying out an aging shown in Figure l. The-only material difference test according to the principles elaborated above. lies in the fact that the scale by which the amount ‘The test specimen, cylindrical in form, is cut 40 of indentation by the tubular member is deter mined is mounted on the canopy in Figure 2. from the material to be tested and is made of a The specimen is held in place and the indenta size which will fit closely in to the specimen hold tion is actually measured by turning the base 22 er‘of the apparatus described in either Figure 1 of the apparatus upward a given amount. That ‘or 2. In practice, I have found that it is con venient to use a cylindrical specimen having an 45 is, in performing the test, the specimen is put in area of one square inch, which means its diam place, tubular member 28 is lowered to contact the upper surface of the test specimen, it is eter should be 1.129 inches. It have found it locked in place, and then the required amount convenient, also, to cut the specimen with a die made for the purpose. Any desired lubricating of indentation is made by turning the base up fluid which will not attack the material being 50 the given amount. Theamount by which the tested, such as a soapy solution can be used dur base is turned up is gaged by means of the scale ing the cutting. It is desirable that the speci 26 and index mark 26.. The remainder of the procedure in carrying out the test is identical men have relatively smooth edges so that it will fit the specimen holder closely, and also so that with that described in conjunction with Figure 1. it can be locked securely in the holder without Since certain changes may be made in the deformation. After preparation of the sample above construction and different embodiments of it is inserted into the sample holder so that its the invention couldlbe made without departing upper face contacts the lip ll shown in Figure 1, from the scope thereof, it is intended that all and it is then locked in place by assembling the matter contained in the above description or how it is ‘used in a test assembly, I shall now de specimen holder. 60 shown in the accompanying drawings shall be Having prepared and mounted a specimen in interpreted as illustrative and not in a limiting the holder the assembly is placed in the appara sense. It is also to be understood that the fol tus and the tubular member is is lowered until lowing claims are intended to cover all or the the ball point l9 just makes contact with the generic and speci?c features of the invention upper surface of the specimen, as is shown in 65 herein described and all statements of the scope Figure 4. When the surface of the specimen of the invention which, as a matter of language, has been found, the plunger is carried or forced might be said to fall therebetween. into the specimen for a desired amount _of in The invention described herein may be manu dentation, for example about 31, of _an inch. factured and used by or for the Government of Since the threads on tubular member 18 can 70 the United States of America for governmental be calibrated with relation to the scale on plate purposes without payment of any royalty thereon IS the indicator 20 can be used to determine just or therefor. ' exactly how far the ball point is forcedinto the Having described my invention what I claim specimen. I have found it convenient to use a as new and desire to secure by Letters Patent of pitch of thread on tubular member [8 of 0.025 75 the United States is: ‘ . - 2,412,0885 terial to be tested, a canopy cooperatively thread 1. The method of testing gasket materials for their sealing quality;'comprising, pressing a n02, . ed to engage said cylindrical member, a tubular zle against a specimen to indent the material a ‘ penetrator member guided in longitudinal move given amount thereby to form a chamber sealed by said material, covering the exterior portion of the material outside of said chamber witha liquid, applying gas pressure to the inside of said chamber until leakage occurs, and measur ing the pressure at which the leakage occurs as an index of the sealing quality of the material. 2. A compressible gasket material testing unit comprising, a base having therein a cylindrical threaded member to hold a specimen of the ma ment‘ and supported ~ by said canopy, locking means’ to hold said‘ tubular member in ?xed posi tion while the specimen is brought into contact therewith and indented thereby, a ?uid supply I‘ for application of fluid pressure to said specimen through said tubular member, said tubular mem 10 ber and its point of contact with said‘ specimen forming a ?uid escape revealing structure. ALBERT D. SWENSEN.