Abstract: Push fit coupling and method for connecting two fluid lines. The coupling includes a first element having a plug-in opening, a second element insertable into the plug-in opening, a retaining device for detachably holding the first and second elements together, and a valve, insertable into the plug-in opening, located on a front face of the second element.

Abstract: A quick connector housing element includes an elongated barb design for coupling the female housing to a tubing member. The elongated barb design includes a generally cylindrical sealing surface proximate a terminal end of the female housing. The sealing surface of the elongated barb enhances sealing properties between the female housing and the tubing and provides other advantages especially in connection with the use of multilayer tubing. Further, an O-ring is disposed about the sealing surface to provide a better seal.

Abstract: A process for controlling the nitriding effect of a nitriding bath of a salt melt containing alkali cyanate for the nitridation of iron and iron alloys wherein the nitriding effect of the bath is maintained in a specific range by determining the voltage occurring at an electrode of a solid electrolyte which conducts oxygen ions immersed in the nitriding bath.

Abstract: A standstill heating system for vehicles, especially for motor vehicles with a liquid-cooled internal combustion engine and with a controllable heater circulation equipped with at least one heat-exchanger, through which flows air intended to be heated and to be fed to the passenger space in the warmed-up condition; a line in communication with the liquid jacket of the internal combustion engine is thereby provided which includes a circulating pump and a heater apparatus whereby this line terminates in the heater circulatory system upstream of the control member controlling the quantity of flow through the adjoining heat-exchanger; a closure valve is also arranged in the heater circulatory system upstream of the place where this line terminates which prevents a return flow of the heated-up cooling liquid during standstill heater operation in by-passing relationship to the heat-exchanger.