Chapter CLVIII: Section 106: Doors, Manholes and Covers

(_See also p. 242._)

=2582. Screw plug,= with two lugs to screw it up by a plain bar placed between them.

=2583. New form of manhole door.=

=2584. Screw fixing= for a plug, door, or valve, quickly released or secured.

=2585. Hollow plug,= with square recess for a key or spanner. Flush plug.

=2586. Soot door.=

=2587. Funnel plug,= for filling oil reservoirs, &c.

=2588. Wrought iron or steel manhole door,= dished.

=2589. Oven door,= lifts out of the catch by leaving sufficient play in the top hinge.

=2590. Soot door.=

=2591. Soot door= in section, opened by pulling outwards and downwards; the hook at top prevents it falling out.

=2592. Screw cap or cover.=

=2593. Revolving door.=

=2594. Sliding door= for furnaces, &c. The weight of door may be relieved by rollers at top, as shown.

=2595. Door or manhole= held up by two wedges.

=~S~ traps. ~D~ traps.= These are divided chambers, or bent portions
of pipes, designed to always contain a well of water so as to cut off
any currents of air or gases that would otherwise pass along the
pipes.

=Street manholes= and lampholes are round, rectangular, or oval
covers, strongly made to carry street traffic, and fitted in strong
cast-iron frames, so as to be easily removable, and yet practically
air-tight. Those fitted over sewer manholes are frequently provided
with charcoal filters to arrest foul gases.