Abstract: A gate valve having a pair of aligned flow passages with a common central axis, with a pair of seat mounts and respective seats facing each other, and forming the walls of a groove with a bottom, their sealing planes tapering toward one another. A riser rises above these seats, with a cap. An actuator rod slides through the cap and mounts and moves an unperforated gate to control flow through the seats. A releasable latch can join the cap and the gate to hold it in its most open position until overcome. A deformable nub is carried by the gate to act as a drag when the gate is moved.

Abstract: A joinder of thermoplastic pipes. Current is passed through a coil disposed between the pipes while a clamp is applied to the joinder. The clamp exerts a prevailing force. The coil is rotatable to facilitate alignment of its leads. The current from a power supply is preferably applied for the same time period for all joinder sizes, the current being adjusted to provide correct heat for various sizes.

Abstract: A pipe coupling particularly adapted for use with plastic pipe carrying fluid at high pressure has a body section from which there extend in the axial direction, two concentric sleeve sections with a concentric annular space between them. The end of a pipe to be coupled is fitted over the internal sleeve and an annular wedge is placed in the annular space between the pipe and the external section. A nut having an annular sleeve is threaded to the external section so that the annular nut sleeve enters the annular space and engages the wedge. Torquing of the nut urges the wedge along a camming surface into tight engagement with the pipe, thus deforming it to prevent its withdrawal from the coupling. The tightness of the coupling is enhanced by variation of the diameter of the internal sleeve in the vicinity of the wedge and by ridges on the internal sleeve into which material of the pipe is forced by the wedge to flow.