Section 89.—VALVES AND COCKS.

Of the almost innumerable varieties of valves and cocks in use the following are selected as types without reference to special uses, each type having its peculiar value, and the drawings are only intended to indicate the special features of each type without such details as may be varied to suit each particular requirement or application.

[1611]. The common plug cock.

[1612]. The same, but with screwed gland.

[1613]. 2-way or 3-way plug cock, with packed gland.

[1614]. Hollow plug blow-off cock, with packed gland.

[1615]. Back pressure or check valve, self closing.

[1616]. Ball valve and guard, self closing.

[1617]. Indiarubber disc and grating valve.

[1618]. Double flap indiarubber or leather and grating valve.

[1619]. Simple flap valve faced with rubber or leather.

[1620]. Rocking or rolling valve. For opening and closing gradually and easily against pressure.

[1621]. Roll-up valve. For same purposes as the last named.

[Larger plate.]

[1622]. Sector full-way screw down valve, shown closed; when open the disc is up in the chamber out of the waterway.

[1623]. Double face valve; the spindle is screwed into the stuffing-box neck and the lower valve, the upper one being pinned to the spindle; the thread in the lower valve is twice the pitch of the upper thread.

[1624] & [1625]. Spring relief valves; the springs are adjusted to blow off at any stated pressure, which may be regulated by a screw or nut (not shown).

[1626]. Weighted lever relief valve or safety valve.

[1627]. Reducing valve, can be adjusted by the balance weight to pass fluids from a high pressure to any lower pressure.

[1628]. Another form, with spring balance adjustment and equilibrium valve.

[1629]. Equilibrium valve.

[1630]. Equilibrium valve, not steam tight, but serrated, to cut off gradually, employed for governors of steam engines.

[1631]. Equilibrium cylindrical grating valve, may be used to open and close either by vertical or revolving motion.

[1632]. Common throttle or butterfly valve.

[1633]. Duplex throttle or damper for a three-way pipe or flue.

[Larger plate.]

[1634]. Hydraulic high-pressure check valve, with long guide wings.

[1635]. Hydraulic plug or spindle valve and seating; all seatings for high pressure should be narrow and hard.

[1636]. Duplex or Ramsbottom safety valve; each valve serves as a fulcrum by which to lift the other. One fulcrum point should be jointed to the lever and the latter move in a vertical guide, or else the point of attachment of the spring to the lever be placed below the level of the valve seatings.

[1637]. A modification of the last named.

[1638]. Pass valve, used for pneumatic despatch tubes.

[1639]. Oscillating lever duplex valve.

[1640]. Simple radial disc valve or sluice.

[1641] & [1642]. Oscillating cylindrical valves. Corliss valves; sometimes made tapered or conical.

[1643]. Multiple ball valve, for high lift delivery valve of large pumping engines. Balls are of guttapercha, and open and close without shock.

[1644]. Multiple ring valve. The rings open and close in succession, thus avoiding shocks.

[1645]. Double beat ring valve.

[1646]. Double beat equilibrium or Cornish valve. The upper seating can be made of such area as to partly or entirely balance the valve.

[1647]. Multiple ring valve. The indiarubber rings expand and contract over the perforations.

[Larger plate.]

[1648]. Double-beat valve, with sunk seating.

[1649]. Common D slide valve, with three ports.

[1650]. Duplex or double D slide.

[1651]. Another form, partly in equilibrium.

[1652]. Equilibrium slide valve, with circular packed trunk on back, of area sufficient to balance the face area of valve.

[1653]. Similar result obtained by a piston and link.

[1654]. Equilibrium piston valve employed in lieu of the slide valve. A steam pipe, B B exhaust.

[1655]. Gridiron slide valve.

[1656]. Common plate slide valve or sluice, used for blast pipes.

[1657]. Floating ball valve, for automatic discharge of air from water mains.

[1658]. Ordinary double-faced sluice valve, lifts clear of the water way.

[Larger plate.]

[1659]. Single face sluice valve, for sewage water, &c.

[1660]. Flap sluice valve. Tidal outlet valve.

[1661]. Diaphragm valve.

[1662]. Oscillating disc valve, for gas.

[1663]. Large 3 or 4-way plug cock.

[1664]. Finger valve, closed by a spring.

[1665]. Taper cone valve, for gradually closing an outlet.

[1666]. Dome valve, used for hot blast, hot gases, &c. This form retains its shape when heated, expanding evenly.

[1667]. Common floating ball tap.

[1668]. Three-way air valve.

[1669]. Duplex slide, used to close a number of openings at once.

[1670]. West’s spiral valve, with indiarubber cord which expands and contracts over a spiral perforated groove.

[1671]. Dennis’ self-lifting valve. The valve is kept to its seat by the pressure being admitted on to its back through small hole A; when the larger hole B is opened by the spindle the back pressure is relieved and the valve lifted by the pressure below its conical underside.

[1672]. Common cone plug.

[Larger plate.]

[1673]. Equilibrium plug or cylindrical valve, double ported.

[1674]. Another form of self-lifting valve. See [No. 1671] for description.

[1675]. Compound flap valve.

[1676]. Indiarubber pump valve.

[1677]. Venetian shutter or compound butterfly valve.

[1678]. Bye pass used to allow a small flow when the main valve is shut off. Used also to equalise pressure on both sides of a large valve to enable it to open easily.

[1679]. Bell and hopper, or cup and cone; used for blast furnaces, coke ovens, and gas generators.

[1680]. Cup valve and suspended weight.

[1681]. Four-way valve for hot water pipes, &c.

[1682]. Oscillating valve.

[1683]. Gas purifier centre valve, for four purifiers; to work one purifier off and three on, or all four on at once. It is similar in plan to [No. 1684], but has an additional top valve which allows the gas to pass into the fourth purifier; the top valve has an independent sleeve and lever motion.

[1684]. Gas purifier centre valve, employed to deliver and discharge gas into and out of any one, two, or three out of four purifiers. The motion of the gas is shown by the arrows.

[1685]. Conical grating valve with radial slots, opened or closed by revolving motion.