Gasket testing

Torque test fitting/pipe connections, including gasket tests... 

Commercial-grade nitroparaftins are shipped and stored ia ordinary carbon steel. However, wet nitroparaftins containing more than 0.1—0.2% water may become discolored when stored ia steel for long periods, even though corrosion is not excessive. Aluminum and stainless steel are completely resistant to corrosion by wet nitroparaftins. Storage ia contact with lead (qv), copper, or alloys containing these metals should be avoided. Polymeric materials for gaskets, hoses, and connections should be tested for thek suitabiHty before exposure to nitroparaftins. 

R. A. Mercuri, R. A. Howard, and J. J. McGl meiy, Ndranced High Temperature Test Methodsfor Gasket Materials, Automotive Eng 97, 49—52 (July 1989). 

Specifications and Standards Test Methods. Ethylcellulose is cleared foi many apphcations in food and food contact under the Eedeial Eood, Dmg, and Cosmetic Act, as amended. Examples include binder in dry vitamin preparations for animal feed, coatings and inks for paper and paperboard products used in food packaging, and closures with sealing gaskets for food containers (44). Methods of analyses ate given in ASTM D914-72 (19), NationalFonmila XIV, and Food Chemicals Codex II. 

Another way to study corrosion in pipe lines is to install in the line short sections of pipe of the materials to be tested. These test sections should be insulated from each other and from the rest of the piping system by means of nonmetalhc couphngs. It is also good prac-tice to provide insulating gaskets between the ends of the pipe specimens where they meet inside the couplings. Such joints may be sealed with various types of dope or cement. It is desirable in such cases to paint the outside of the specimens so as to confine corrosion to the inner surface. 

HEPA filters consist of a filter pack sealed into a case. The filter pack or core is made by pleating a continuous web of fiberglass paper back and forth over corrugated separators. The filter pack is sealed into a full-depth wood or steel casing using a elastomeric sealant. Gasketing is a critical item to ensure that the filter passes the air leakage tests. 

PTFE gaskets were specified for a section of plant that handled acid. As they ai e fragile and expensive and as an extensive series of tests using water had to be carried out during startup, temporary nitrile rubber gaskets were used during this period. You can guess what happened. One of them was left in position and corroded. 

The instruments for the HT-HP filtration test consist essentially of a controlled pressure source, a cell designed to withstand a working pressure of at least 1000 psi, a system for heating the cell, and a suitable frame to hold the cell and the heating system. For filtration tests at temperatures above 200°F, a pressurized collection cell is attached to the delivery tube. The filter cell is equipped with a thermometer well, oil-resistant gaskets, and a support for the filter paper (Whatman No. 50 or the equivalent). A valve on the filtrate delivery tube controls flow from the cell. A nonhazardous gas such as nitrogen or carbon dioxide should be used for the pressure source. 

Fig. 1.49 Crevice corrosion, (a) Crevice resulting from the joining of two plates of steel and b) crevice due to a gasket between two flanged pipes (c), (d) and (e) show the method used by Streicher to test different steels for their propensity to crevice corrosion two plastic cylinders are held onto the sheet of metal by two rubber bands of the same size, giving rise to three different types of crevices in duplicate...

Figure 19.21 shows the types of crevices used by Wilde " for studying crevice corrosion and pitting of Cr-Ni-Fe alloys in the laboratory and in the field. Types 1 and 5 were used for anodic polarisation studies in nitrogen-saturated 1 mol dm NaCl and in aerated 3-5 mass% NaCl, respectively, and it can be seen that attachment to the conducting lead is by means of a Stern-Makrides pressure gasket Types 3 and 4 were used for field tests... 

Where definite loss of color by bleaching is noted, the content and container should be inspected to determine the cause. If correctable, such as a faulty gasket, broken container, etc, the gasket is changed or the powder is transferred to another container. A new strip of test paper is inserted and the proplnt replaced in storage with the container definitely marked to insure reinspection at the end of one year. 

Fig. 6.—Large magnet with test chamber enclosing pole pieces and dumbbell assembly windowed cover and gasket have been removed from test chamber.

The samples most commonly tested in compression are foams and rubbers, which experience compressive forces during use. Very often, the polymer foams that experience compression are not readily visible to us, even though they are all around. Polymer foams are widely used in carpet underlay, upholstery, shoe insoles, backpack straps, bicycle helmets, and athletic pads. Solid rubbers are much more visible, including automobile and bicycle tires, gaskets and seals, soft keys on calculators, and shoe soles. 

Tests showed that Teflon gaskets containing more than 0.35 wt% of sorbed trichloroethylene were potentially hazardous in contact with liquid fluorine. 

A total of four Co and Fe based alloys were procured from a commercial source. Disks were punched from the foil and mounted into VCR vacuum fittings, with a nickel gasket on one surface and the sample in direct contact with the VCR sealing surface on the other. The sample assemblies were leak tested and verified leak tight to 2x10 7 sscm He prior to intallation in the permeation test apparatus. 

ISO 3934 2002 Rubber, vulcanized and thermoplastic - Preformed gaskets used in buildings - Classification, specifications and test methods ISO 4649 2002 Rubber, vulcanized or thermoplastic - Determination of abrasion resistance using a rotating cylindrical drum device ISO 4664-1 2005 Rubber, vulcanized or thermoplastic - Determination of dynamic properties - Part 1 General guidance... 

Overall, the main problem with the thin layer flow cell studies was reproducibility. It was nearly impossible to produce equivalent deposits 2 days in a row. The investigations became an endless series of tests to figure out how to improve the substrate, get rid of bubbles, get the right gasket material, and deal with possible IR drop problems. Although some problems were solved and some deposits were formed, very little progress was made toward a better understanding of the mechanism of compound electrodeposition, or ECALE [158]. 

Standard method of test for accelerated ozone cracking of vulcanized rubber [Test method D-1149-64 (reapproved 1970)], pp. 554-560. In 1972 Annual Book of ASTM Standards. Part 28. Rubber Carbon Black Gaskets. Philadelphia American Society for Testing and Materials, 1972. 

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