80. Reducing-valve, which can be adjusted by the balance weight to pass fluids from a high to any lower pressure.
81. An equilibrium-valve.
82. India-rubber disc and grating valve.
83. A four-plunger valve, used for double-power hydraulic lift-cylinders employing a trunk piston For the low power the pressure-water acts on both sides of the piston; for the double power it acts only on the back of the piston, the front side being then open to the exhaust.
84. Sketch of the Corliss valve-gear, operated by a single eccentric. It has two steam and two exhaust valves of an oscillating cylindrical type, worked from pins on a rocking wrist-plate. The steam-valves have trips regulated by the governor.
85. Corliss valve, with rectangular rocking spindle.
86. A favourite type of vertical overhead cylinder screw engine, with half-standards and distance rods, one, two, or three cylinders, simple or compound. The condenser is usually in the back standards and the pumps behind.
87. A pedestal bearing, with four brasses and set-screw adjustments.
88. A hydraulic oil-pivot for vertical-spindle. Oil under pressure is forced into the channels between the bearing faces, the area and pressure being adjusted to the load. The surplus oil is returned from the oil-well to the pump.