Garlock valves now close with nearly half the power
Garlock GmbH reduces the torque of its PTFE-lined valves – actuators can now be sized smaller, maintenance made easier
Garlock GmbH presents its evolved Butterfly actuators at Valve World in Düsseldorf. Thanks to evolutions in the liner and disc, friction values were reduced to the point where significantly lower torques are required to shut off or throttle the flow. For instance, the torque of the DN80 valve was lowered from 48 Nm to 29 Nm (a reduction of 40%). At larger diameters, it was possible to reduce torque even more. For the DN300, now only 274 Nm are needed instead of 520 Nm (a reduction of 47%), whereas the DN600 now only needs 2,056 Nm instead of 3.990 Nm (a reduction of 48%). These statements are based on extensive measurements – measured dry at 21°C. Thanks to the product refinement, Garlock valves now feature the lowest torques on the market.
When maintenance is required, case liners and flap discs made from other materials can now be more easily exchanged for parts made from high-quality PTFE, which offers better chemical, abrasive and thermal resistance, all without having to replace the actuator. This is because Garlock was able to compensate for the higher coefficients of friction resulting from PTFE-on-PTFE contact by using the new liner technology. For example, now it is generally possible to replace a valve with a PFA liner and PTFE disc with fittings consisting entirely of PTFE. In the past this proved difficult in cases where the actuator was designed for the lower coefficients of friction resulting from PTFE-on-PFA.
Polytetrafluoroethylene (PTFE) is the most chemically stable of all plastics. It is also highly resistant to ageing, and has high dielectric strength. Garlock goes a step further and improves these mechanical and chemical properties during component manufacture at the factory in Neuss. This is done by isostatically pressing the PTFE granulate. The high degree of compaction of the material ensures an absolutely homogeneous lattice structure, minimising permeability while enhancing both hardness and tensile strength.
With its above-average service life, reduced maintenance costs and smooth operation, Garlock performs well wherever corrosive, abrasive or toxic media have to be managed – such as in the chemical, petrochemical and chlorine industries, and in the electroplating and paper industries. The GAR-SEAL product line offers a variety of solutions for these applications. If abrasive and static charging need to be avoided as well, a SAFTEY-SEAL valve is the right choice. The MOBILE-SEAL line is tailored to the needs of the transportation industry. STERILE-SEAL products enable sterilisation "from the outside" so that process media do not come into contact with steam, making them excellent for use in the pharmaceutical and food industries. The reliability of Garlock valves is not only appreciated by customers in a variety of industries – it's certified according to EN 61508 (SIL-3).
Wherever valves need to be used with actuators is where the new Garlock valves show off their strengths: smaller actuators can be selected for new installations, lowering both procurement costs and energy consumption during operation.
The total cost of ownership is lowered even more if Garlock's pneumatic rotary actuators are used, as these are optimally matched to Garlock valves. The Scotch Yoke actuator – as opposed to one with a rack and pinion design – is impressive, with up to 50% more torque in both the forward and rear range of its switching cycle. This enables additional savings by lowering the size and weight of the actuator while maintaining or reducing compressed air consumption.
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