You are here

Stafsjö’s MP – the eighth knife gate valve generation

In 1928 our knife gate valve manufacturing started in close co-operation with nearby pulp and paper mills. Now it is time for the eighth knife gate valve generation, the MP, which is a result of market driven requirements and experienced engineering throughout the years. Stafsjö has introduced one new knife gate valve every year now the last three years. 2009 we introduced the slurry valve SLV, primarily for the mining business. 2010 we introduced our HL, a slim line version of our HG valve with through-going gate, and now 2011 the MP.

– We are proud to announce Stafsjö’s latest development for the Pulp & Paper Industry. The MP valve represents the new generation of shut-off valves which fully corresponds to today’s market demands such as bi-directionality, full bore and minimum maintenance, says Thomas Carlson, CEO of Stafsjö.

Product features
The MP is a bi-directional full bore valve which together with its special shut-off design makes it suitable for many different applications – it is a true Multi Purpose valve.

MP has a one piece body design in stainless steel. For operation reliability in applications with corrosive or clogging media the valve body comes with integrated purge ports as standard. The MP is also supplied with Stafsjö’s retainer ring system which can be combined with several seat materials and this makes it easy to optimize the valve to specific process conditions. It also offers smooth and cost-efficient maintenance. The valve has a gate support and casted bottom support cams to obtain bi-directional sealing. The gate support is available in different materials.

The top work consists of aluminium beams and stainless steel tie rods which gives good corrosion resistance and stability at maneuvering. Several actuator types are available to choose from as standard as well as accessories.  All remote operated valves are supplied with gate guards in stainless steel.

Sealing principle
When the valve is operated from open to closed position, the gate effectively cuts through the media. This is facilitated by the inner cavity of the valve body and the bevel edged gate. In closed position the gate is pushed against the seat and the gate support ensure a bi-directional sealing together with the bottom support cams that stabilizes the gate.

The gland box is equipped with three layers of our TwinPack and a box bottom scraper, which gives high operation reliability and prevent the media from reaching surrounding environment.

Further information on the valve is available on the product pages, click here...

Stafsjö broaden its product range with the new HL valve

The HL knife gate valve is developed to complement our existing product range with bi-directional knife gate valves with through-going gates. The HL is designed to work under similar process conditions as the well known HG and the high pressure valve HP, but in lower pressure classes. 

– The HL valve represents the first step in our new “Slim line” consisting of compact versions of Stafsjö’s existing product range. Driving forces have been ongoing continuous cost reduction program combined with market driven factors, especially when we are expanding into new business segments. The HL will broaden our product range in high and low pressure applications where we ensure reliability, low cost of ownership and customer satisfaction, says Thomas Carlson, CEO of Stafsjö.

Product features
Stafsjö’s knife gate valve HL is bi-directional and tight in both pressure directions. It is a full bore valve with excellent flow characteristic. HL is equipped with a through-going gate for secure shut-off of static and high concentrated media, often a problematic duty for traditional valves. HL is developed for severe operating conditions with pulp, caustic liquor, reject and waste, but it is also suitable for other applications with powder, slurry and ash.

HL has a two piece valve body in stainless steel with purge ports and integrated guiding pads. PTFE body gaskets gives a secure sealing between the body halves. The valve is equipped with a gate in stainless steel and removable retainer rings which simplifies the change of seats. The valve is modular designed meaning that it can easily be customized with gate, seats and box packings according to media and requirements, as well for actuators and accessories.

Sealing principle
When the valve is fully open the bore is practically entirely free from cavities and as a consequence flow characteristic is excellent. In this position the two seats are protected by the retainer rings and the gate, preventing media from entering the valve body.

When the valve is operated from opened to closed position, the valve body, gland boxes and the seats gives the gate continuous support for reliable and secure shut-off. Internal guiding pads make this operation smooth and easy. When the valve closes some media can enter the valve body, but it is returned to pipe line when the valve is operated to open position. Stafsjö’s unique gland box packing, TwinPack™, gives a secure sealing where the gate exit the valve body and assures that no media reaches surrounding environment.

Further information is available on the product pages, click here...

Stafsjö expand its product range with slurry valves for mining and mineral processing

Stafsjö’s knife gate valves SLV and SLF are developed for slurry and abrasive applications where operation reliability and low life cycle cost are emphasized. The SLV is a lugged version while the SLF is fully flanged and especially suitable on old non-centred pipes or low pressure applications. 

The valves are a result of a long-term and customer oriented product development. Our profound knowledge of knife gate valve technology together with pioneering design and material selection form the foundation for this product.

– This latest product development is a clear signal and shows our intentions to the market. In our growth strategy our primary focus lays on expansion into other business segments than we traditionally have served. I am convinced that both the SLV and SLF will further strengthen our range of knife gate valves and help us in achieving profitable growth, says Thomas Carlson, CEO of Stafsjö.

Product features
The SLV valve is bi-directional and has full bore for maximum flow capacity. It is modular designed and consist of a compact epoxy coated one or two piece valve body in cast iron. The top work can easily be provided with different actuators and accessories. The valve can also be customized with hard chromed gates in different alloy and its unique seat construction guarantees excellent operation together with abrasive media.

Sealing principle
The valve's seats are developed for long-life service in applications with slurry. The seat and its material composition together with embedded reinforcement rings guarantee safe operation during tough operating conditions.

The seats are flexible in the axial way. When the valve is fully opened the seats expand and seals towards each other thus forming a tight extension of the pipe line where only the seats are exposed to the media. Minimal seat cavity prevents accumulation of media in the bore. 

The suspension of the seats in combination with the unique shape of the gate plus the internal gate support minimizes wear on the seat during actuation. When the valve is closed, the seats are compressed and seals efficiently towards the gate in both pressure directions. Residues will be droped out either through the bottom of the valve or through the purge ports when the bottom cover is mounted.

Further information on the SLV and SLF valves are available on the product pages, click here...

Stafsjö invest in a new multi-operations machine

By June 11th 2007 Stafsjö inaugurated a new multi-operations machine (Uniport 6000) from the dutch company Unisign. The portal machine is capable to prepare complete valve bodies and their gates up to DN 1600. The machine is equipped with more than 100 tools and it is designed to do multi-sided machining without any manual work. With Uniport 6000, we can increase and improve our production of larger knife-gate valves, says Thomas Carlson, President of Stafsjö Valves AB. An investment like this also involves better capacity to meet the increased demand for lager knife gate valves.