Sliding gate control valve for precise, economic and quick control
This article introduces the sliding gate control as a solution in applications required to control liquids, vapour and gaseous media precisely, quickly and economically.
The innovative design of the sliding gate control valve offers end-users a reduction in weight of 90% and a reduction in required actuating force of 90%, compared to a globe style valve.
Read on to understand the innovative design features and the consequential application benefits of Schubert & Salzer’s sliding gate control valve.
How does the sliding gate valve work?
A sealing plate fixed in the body at right angles to the flow direction has a certain number of crossways slots of equal height. A rotationally fixed disc with the same arrangement of slots is moved at right angles to this, thereby changing the flow cross-section. The prevailing differential pressure presses the moving disc against the fixed disc and seals it.
This innovative design brings many comparative advantages and application benefits.
Excellent leak tightness and low leakage rates
When traditional control valves with a metal seat are installed in an application, they are highly susceptible to scoring, which essentially results in costly repairs and dangerous leakages of steam.
The sliding gate control valve by Schubert & Salzer utilises a surface seal, rather than an annular seal, between the 2 moveable slotted discs. The pressure of the medium against the moveable valve plates actually boosts the sealing function of the valve. As a result of this surface sealing system, leakage rates of less than 0.0001% of the Kvs value are achieved.
Application benefits: Reduces leakage, increases safety levels and significantly reduces costly valve repairs and replacements.
Short control stroke
The control stroke of the sliding gate control valve is at the very most, only 8mm. This short stroke not only results in short operating paths and times, but it also significantly reduces the stresses on both the packing and on the actuator operating the valve. With the sliding gate valve, both the actuator and the packing are subject to much lower loads.
Application benefits: Provides longer working life for both actuator and packing, reduces energy consumption & offers quick & efficient operation.
Optimal flow control
The sliding gate control valve avoids cavitation problems in the valve and operates quietly by lowering turbulence.
In applications where the local pressure of a liquid falls below it’s vapour pressure, vapour bubbles are formed in areas of higher pressure. When these vapour bubbles come into contact with solid boundaries (i.e. the valve body), they collapse with force causing what is known is as cavitation damage.
Cavitation damage manifests itself as noise, vibration, accelerated corrosion and limited valve flow.
In the case of the sliding gate control valve, these dangerous cavitation zones are external to the valve, precisely 1-2 metres beyond the valve. This means the harmful vapour bubbles collapse around the center of the pipeline, where they cause no damage to the valve body.
Application benefits: Reduced valve wear and maintenance costs, increased productivity and longer operation.
High efficiency and low power consumption
As the throttling elements are designed to be perpendicular to the flow of the media, closure of the valve is transverse to the direction of flow and not against it, as with traditional globe valves.
Due to this innovative design, the sliding gate valve only needs 10% of the force for positioning and closing that a standard globe valve of the same nominal size and the same differential pressure would need.
Application benefits: lower energy consumption and ability to use much smaller valves and actuators, reducing cost and space requirements.
Reduced weight and space requirements
As described above, the low actuating force and the short stroke allows the use of smaller actuators to be used. Furthermore, a sliding gate valve is extremely narrow in construction and fits easily between 2 flanges.
A DN150/6” sliding gate valve, including actuator, weighs only 14.2 KG. This compared to 150KG for a globe or seat valve of the same size.
Application benefits: reduction in size and weight makes installation and maintenance easier and more cost effective – the valves can be installed, removed and maintained by a single person.
There are application benefits of installing the Schubert & Salzer sliding gate control valve above and beyond those mentioned here. For more information about this innovative product, please read the product brochure by clicking here. Alternatively, you can contact Schubert & Salzer directly by visiting their PIF profile.
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