What kind of sleeve do I need?

[ldmogollonm]

Hi!

I need to select a knife valve wich works in heavy conditions: hot watter (100 °C) and slag... I thought one designed for slurry (with rubber at the seat) will be Ok, but now I´m not that sure because of the abrassion will damage the rubber, any help?

 

[gerhardl]

As you know knife (knife-gate) valves comes in a large number of construction and materials. With slag/hot water the constructional details as well as the correct tyes and material for sealing will be important.

There is also always the question if a knife-gate valve in itself is the correct choice. A complete description af the media, pressure, operation modus and size will give a better answer. Does the slag consiist of abrasive particles or media that can cling to blade and sealings?

For fairly 'normal' rough cases you will be well served with EPDM sealings up to 120 deg C, or else PTFE or FEPM (caution, chemicals? Oils?).

My recommondation is to be sure to have a bi-directional valve, without pockets (sludgde gathering in pockets), sideways slightly reduced (extra knife support), stem linked 'elastic' to gate (to avoid sidewise extra wear by forcing the blade direction with leverage).