Gland less piston valve

Rememberwhen the piston valve is first put under service, the cover nuts shouldbe tightened lightly and evenly with the valve in closed position, thiswill enable to settle the rings firmly around the piston. This willincrease the life of the rings & failure to this may result inpremature leakage. Also note that the cover nuts should not be tightenwithout the Belleville washers.

• All nuts have left hand threads.
• Thepistons are accurately machined & carefully finished, if it isnecessary to hold the piston while fitting then grip it between a softwooden clamp to avoid damaging the surface.
• Open the valve wide.
• Remove the cover nuts.
• Screw down the spindle (turn right) to lift the cover off the studs.
• Turn the cover so that it rests on top of the studs.
• Screw spindle up (turn Left) to withdraw piston from rings.
• Lift off cover parts, taking care to avoid scratching the piston.
• Use only genuine WOODLAND valve rings.
• Inserta new ring & drive it gently home using a punch / a short barmetals or wood having a slight small diameter than that of the ring.Tap the punch with the hammer lightly & drive the ring till thebottom of the bore.
• Replace the lantern bush, which should enter the bottom bore & sit flat on the ring.
• Insert the top ring by the same way as the bottom.

Replacing the valve cover

Replacing new piston & sealing ringsis a simple matter, as they are provided with a machined Horseshoeslot. In some cases the piston are fitted by means of a split washerand nut.

To remove old sealing ringsuse a tang of an old file or screwdriver bent at right angle to form ahook, now pull out the top ring, lantern bush & the bottom ring oneafter another.

Life of the rings depends on the above process as & when required until the rings are worn out & needs replacement.

No undue forceshould be used in tightening the piston valve nuts. They should moveeasily with a standard spanner of the corresponding size & shouldbe tightened equally to avoid tilting of the cover. Please do not use awheel spanner on the hand wheel since there is no use of any undueforce to shut the piston valve, it may simply damage the spindle.

It is importantto follow instruction no.1, If the cover nuts are tighten down with thevalve open then the bottom ring may be compressed in the passage andget damaged by the Piston when the valve is again closed.

When a leak develops it is easy to correct it with an ordinary spanner.