Pipe Gasket Research Articles

A new monitoring approach for sustainability assessment of subsurface utilities gasket materials against gasoline and chlorinated solvents: Field evaluation and model development

Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (ke, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.

Permeation of gasoline through DI pipe gaskets in water mains

Sorption tests and pipe‐drum experiments were conducted to study permeation of monoaromatic compounds in gasoline through five polymeric materials used in ductile‐iron (DI) pipe gaskets. Ethylene propylene diene monomer (EPDM) had the highest sorption of premium gasoline, and fluoroelastomer rubber had the lowest. A comparison of gaskets' heel and bulb portions found that the heel sorbed less gasoline, suggesting greater resistance to permeation. Pipe‐drum experiments showed that the order of breakthrough of benzene‐toluene‐ethylbenzene‐xylene compounds for gaskets exposed to premium gasoline was EPDM > chloroprene rubber ≈ styrene butadiene rubber (SBR) > nitrile rubber (NBR). For DI pipes with SBR gaskets exposed to premium gasoline, the benzene concentration after 8 h of stagnation exceeded the maximum contaminant level (MCL). With typical water flow rates in pipes, the estimated benzene concentration did not exceed the MCL. If pipes are to be installed in gasoline‐saturated groundwater, NBR gaskets are preferred over SBR gaskets.

The Excavation, Conservation, Storage, and Display of Rubber Artifacts Recovered From the USS Monitor (1862)

In joint research efforts between the National Oceanographic and Atmospheric Administration, the United States Navy, and the Mariners' Museum, more than 50 rubber artifacts have been recovered from the rotating gun turret and steam engine of the USS Monitor. These rubber items include a glass jar seal, a comb, uniform buttons, and pipe gaskets. Waterlogged rubber artifacts from a highly saline environment present a unique opportunity for examining current conservation issues such as handling, treatment, and storage of rubber objects manufactured during the Civil War. Research into conservation treatments, such as chemical cleaning and electrophoresis, was conducted to determine the efficacy of specific methods to remove chlorides and corrosion products. Oxygen-free storage, using the Mitsubishi RP System, was elected as a preventive conservation step. The opening of the USS Monitor Center, a state-of-the-art laboratory and exhibition gallery for objects from the Monitor, has afforded the opportunity to increase public awareness of conservation processes through interactive exhibits and laboratory viewing stations.

Effect of Chloramines on Ductile‐iron Pipe Gaskets of various eslastomer compounds

Degradation reported from laboratory testing of elastomer sheet materials subjected to chloramines has not correlated to experience in the field for some applications. The effect of chloramines, or any other chemicals, on elastomers in potable water systems is both material‐and‐application specific. The large surface‐area‐to‐mass exposure ratio of, for example, toilet bowl flapper valves, is quite different from the small surface‐area‐to‐mass exposure ratio of ductile‐iron pipe gaskets. To investigate this, side‐by‐side tests of elastomer sheet materials and ductile‐iron pipe push‐on and mechanical joint gaskets exposed to 110 mg/L total chloramine solution were conducted. The push‐on and mechanical joint gaskets were tested in assembled joints. The tests, done over 364 days, revealed that although the majority of the elastomer sheet materials experienced significant visual degradation and large changes in mass, volume, and hardness, the ductile‐iron pipe push‐on and mechanical joint gaskets showed no visual degradation and only slight detectable chlorine penetration.

Patents

Including information on: Closure and self-draining container with a peelable seal Wear indicator for a seal of a suction roll of a paper or board machine Bonded piston seal for power steering Hypodermic-syringe head with tamper-proof seal Rubber composition for the manufacture of sealing components Self-venting movable seal and plunger Seal structure of metal mould Seal receptacle using an expandable liner hanger Unitized fuel cell electrode gasket assembly Method and apparatus for providing a pipe gasket Seal between a drinking container and straw Parallel capillary seal for a disk drive Gasket for use in a metering valve that limits seal intrusion A modular mechanical seal Metal-to-metal seal for ultrahigh pressure systems Brush seal