Feature Valves & actuators
engineered stem-tip geometry (eg vee- or needle-shaped) that fits precisely into a seat over the inlet. The stem is finely threaded, enabling precise flow control. Stem packing provides the seal to atmosphere. Some designs con-
tain a metal-to-metal seat seal; conse- quently, needle valves are a good choice for high-temperature applica- tions. Flow is limited because of the globe-style flow path. Needle valves are a good choice with lighter, less viscous fluids.
For the most precise flow control, consider fine metering valves, typi- cally found in laboratory settings. A type of needle valve with a long, fine stem that lowers through a long, narrow channel, this makes for a pro- nounced globe pattern, ideal for mark- ing fine gradations of flow. Some fine metering valves are not designed to shut off. Quarter-turn plug valves are eco- nomical utility valves. Quarter turn actuation rotates a cylindrical plug in a straight-through flow path. The plug contains an orifice to permit flow. Plug valves are commonly used for low- pressure throttling applications, in addition to shutoff. In a rising plug
Ball valves are ideal for on-off control. Quarter-turn actuation starts or stops flow by positioning a metallic ball in a straight- through flow path
Left: Diaphragm valves provide rapid shutoff and precise
actuation speeds Fast response pneumatic solenoid valves
Gems Sensors & Controls has introduced the energy efficient E Series family of pneumatic solenoid valves, specifically engineered to give fast response and high flow rates in a wide range of air and dry gas applications. With extremely low power consumption from just 0.65W to 2.0W and a robust, nickel plated body and coil housing construc- tion, the valves are highly durable and corrosion resistant. The E-Series solenoid valves are suitable for use in a wide range of applications including medical and respiratory healthcare instru- ments, printing machinery and sorting equipment, automated packag- ing and air monitoring systems. The cylindrical body measures 19mm in diameter and 50mm in length and the valves are available with a variety of seal and o-ring options including Viton, nitrile, EPR and silicone. Versions can be
supplied in multiple 2- or 3-way configurations including normally open, normally closed, multi-purpose and directional control 3-way. E Series valves offer orifice sizes ranging 0.81mm to 1.98mm, and port configurations that include #10-32 straight thread, M5 x 0.8 threads, manifold mount and bottom under-seat port. Gems Sensors and Controls
T: 01256 320244
www.gemssensors.com Universal solution for rod-style actuator applications
The Exlar K Series of linear actuators from INMOCO offers multiple model types, enabling users to chose the option best suited to their application and budgetary requirements. Providing a universal solution for rod-style actuator applications, the actuators use Exlar's patented roller screw technology with its proven reliability and superior load carrying capacity. The price/performance ratio of the K Series electromechanical actuators means that they provide a clean, fast, simple and cost-effective replacement for hydraulic actuation, delivering a solution that offers superior life and performance. With dimensions consistent to those for ISO Metric pneumatic actuators, the units provide a simpler, longer-life alternative to pneu- matic cylinders.
The K series is available with the options of multiple grades of planetary roller screws and an
Process & Control AUGUST 2011
ACME screw for applications where backlash cannot be tolerated.
The design of the roller screws allows them to be accelerated and rotated faster than comparably sized ball screws, while their large contact area allows high force characteristics and provides long life - typically 15 times that of comparably sized ball screws - even in the most demanding repetitive applications.
Its robust design ensures reliable performance in demanding applications. The standard body design provides an IP65 sealed housing and motor mount (when allowed by the design of motor used). This allows the actuators to be used in applications where spray is present without the requirement and cost of special options. INMOCO T: 01327 307600
www.inmoco.co.uk
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valve, as in a needle valve, a tapered plug lowers into an orifice to reduce flow. It differs from a needle valve in its flow path which is straight-through rather than globe patterned. Because of the straight path, the valve is not as effective at providing fine gradations of flow. The rising plug is roddable, which is a good choice if the valve becomes clogged with system media. Swagelok T: +1440/649-5629
www.swagelok.co.uk
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Safety solution protects pipeline valve stations
Hima-Sella has completed delivery on safety solutions at all 20 valve stations along the length of SABIC UK Petrochemicals' 250km Wilton- Grangemouth Ethylene Pipeline (WGEP), one of a number used to link ethylene production plants in the UK. The installations include the replacement of the valve stations' remote terminal units (RTUs) and hardwired valve interlocks with a BS EN 61508 safety system.
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At the valve stations which are in remote locations, a number of parame- ters are monitored including valve positions, upstream and downstream pressures, temperatures, cathodic pro- tection, battery charger status and product flows. Hima-Sella's solution for localised safety within each valve station is the HIMA HIMatrix F35 Programmable Electronic System (PES) which has eight analogue inputs, 24 digital inputs, eight digital outputs, three Fieldbus ports and four configurable Ethernet ports. Hima-Sella T: 01522 789000
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www.hima-sella.co.uk
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