Stafsjö’s HG & HL series are through-going O-port knife gate valves with superior flow characteristics, offering reliable bi-directional zero leakage shut-off on highly concentrated media and static media columns with pressure up to 6 bar.

The HG is Stafsjö’s standard O-port series and the HL series is a slim version of the HG.

The HG & HL knife gate valves can operate on different media such as pulp stock up to 18 % concentrations, liquor, ash, and granulate. The HG & HL series are modularly designed and can easily be customized in materials, with actuators and related automation accessories to fit different process conditions.

Available in sizes ranging from DN 80 – DN 1200 (3″ – 48″) for the HG series and from DN 400 – DN 800 (16″ – 32″) for the HL series.

The HL series is supplied as standard with a two-piece precision machined valve body in stainless steel, which has integrated purge ports and guiding strips. To be able to cope with bi-directional pressures, the HL has the retainer ring system on both body halves. The valve is equipped with a stainless steel gate, duplex material and hard chromed surface are optionally available to increase the wear resistance. The gland boxes are equipped with Stafsjö’s box packing TwinPack™, to ensure no media reaches the surrounding environment. The HG series has a rigid two-piece precision machined valve body in stainless steel or nodular iron.  The HG & HL series feature a high strength top works that provide an essential and precise gate alignment.

The HG & HL automated assemblies come standard with proximity switch sockets to confirm the valve’s opening and closing. The valve design also allows for magnetic limit switches mounting.

The PTFE seats are protected by the gate and retainer rings and the internal back-up o-rings keep the seats constantly pressurized against the gate. Polyurethane retainers and seats are available as an option for abrasive processes and metal seats and retainers option is only available for extreme high temperature process. The gate is guided throughout the entire stroke and operates smoothly through difficult and highly concentrated media. The retainer ring system on both sides of the gate provides a tight seal independent of pressure direction. The gland box sealing system with three layers of Stafsjö’s Twin-Pack ensures that no media reaches the surrounding environment. Extra scrapers or double glands can be used for the most demanding services. The retainer rings hold the seats and the back-up o-rings in the exact correct position as the gate strokes. They are mechanically locked and can easily be removed for seat change. Both the retainer rings and seats are available in different materials which makes it easy to customize HG & HL series to different process conditions.

Stafsjö also offers two high-pressure versions HP & HPT series for pressure up to 10 bar and the HX series for extreme high pressure applications up to 20 bar.