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heavy pieces of blubber on deck. -- Junk ring. (a) A packing of soft material round the piston of a steam engine. (b) A metallic ring for retaining a piston packing in place; (c) A follower. -- Junk shop, a shop where old cordage, and ship's tackle, old iron, old bottles, old paper, etc., are kept for sale. -- Junk…

A kind of cage inserted in a stuffing box and surrounding a piston rod, to separate the packing into two parts and form a chamber between for the reception of steam, etc. ; -- called also lantern brass.

is uncovered by the valve, for the admission or release of steam, at the instant when the piston is at end of its stroke.

ft, under Health. -- Lifting pump. (Mach.) (a) A kind of pump having a bucket, or valved piston, instead of a solid piston, for drawing water and lifting it to a high level. (b) A pump which lifts the water only to the top of the pump, or delivers it through a spout; a lift pump. -- Lifting rod, a vertical rod lifted…

A lining within the cylinder, in which the piston works and between which and the outer shell of the cylinder a space is left to form a steam jacket.

power of (a single-cylinder beam engine) by adding a small high-pressure cylinder with a piston acting on the beam between the center and the flywheel end, using high-pressure steam and working as a compound engine, -- a plan introduced by M'Naught, a Scottish engineer, in 1845.

called a reproducer, so as to copy accurately on a smaller scale the motion of the engine piston. The resultant of these two movements imparts to the reflected beam of light a motion similar to that of the pencil of the ordinary indicator, and this can be traced on the sheet of ground glass, or photographed.…

to move without giving passage to air, water, or steam; as, to pack a joint; to pack the piston of a steam engine.

The substance in a stuffing box, through which a piston rod slides.

One of the series of disks or pistons in the chain pump. Knight.

ointed system of links, rods, or bars, by which the motion of a reciprocating piece, as a piston rod, may be guided, either approximately or exactly in a straight line. Rankine. (b) (Mus.) The ascending or descending of two or more parts at fixed intervals, as thirds or sixths. -- Parallel rod (Locomotive Eng.), a met…

Motion; movement, regular or irregular; as, the play of a wheel or piston; hence, also, room for motion; free and easy action. "To give them play, front and rear." Milton. The joints are let exactly into one another, that they have no play between them. Moxon.

A long solid cylinder, used, instead of a piston or bucket, as a forcer in pumps.

r Atmospheric. -- Pneumatic syringe, a stout tube closed at one end, and provided with a piston, for showing that the heat produced by compressing a gas will ignite substances. -- Pneumatic trough, a trough, generally made of wood or sheet metal, having a perforated shelf, and used, when filled with water or mercury,…

, Center, etc. -- Back pressure (Steam engine), pressure which resists the motion of the piston, as the pressure of exhaust steam which does not find free outlet. -- Fluid pressure, pressure like that exerted by a fluid. It is a thrust which is normal and equally intense in all directions around a point. Rankine. --…

and partly by the direct action of the steam on the water, without the intervention of a piston; -- also called vacuum pump.

structed, for raising or transferring fluids, consisting essentially of a moving piece or piston working in a hollow cylinder or other cavity, with valves properly placed for admitting or retaining the fluid as it is drawn or driven through them by the action of the piston.

cating air. Dryden. Reciprocating engine, a steam, air, or gas engine, etc., in which the piston moves back and forth; -- in distinction from a rotary engine, in which the piston travels continuously in one direction in a circular path. -- Reciprocating motion (Mech.), motion alternately backward and forward, or up an…

shaft is produced by the direct action of the steam upon rotating devices which serve as pistons, instead of being derived from a reciprocating motion, as in the ordinary engine; a steam turbine; -- called also rotatory engine. -- Rotary pump, a pump in which the fluid is impelled by rotating devices which take the p…

sphere. Siemens. Rotative engine, a steam engine in which the reciprocating motion of the piston is transformed into a continuous rotary motion, as by means of a connecting rod, a working beam and crank, or an oscillating cylinder.