About Valco actuators and accessories

About actuators

Two position valves operate, as their name implies, in only two positions: Load and Inject, or Position A and Position B. Multiposition valves operate in continuous revolutions by incremental steps, totally unlike the back and forth switching of two position valves.

There are several ways to actuate each type of valve: manually, with an air or pneumatic actuator, or electrically (with a standard or microelectric actuator). All of these can be supplied with optional standoff or right angle drive.

We support these actuation methods with a number of controllers and interfaces for computer-controlled systems. Some features are common to both two position and multiposition actuators, while other features and controllers are specific to one type or the other.

Manual actuation

Two position
Simplicity and low cost are the main advantages of a manually actuated valve. Some models can be ordered with position feedback, an option which sends a signal to start a data system when the valve is switched.

Multiposition
Except for low pressure Cheminert multiposition valves, we recommend that multiposition valves be purchased with air or electric actuators. While a manual detent assembly is available, the higher turning torque of our other multiposition valve designs makes them more difficult to position accurately by hand.

Air actuation

Air actuators are useful in situations where any spark could be disastrous or where there is no electricity available. They are small, relatively inexpensive, very rugged and dependable, and field-serviceable.

Low gas consumption and lightweight, compact construction make the air actuator suitable for aerospace flight hardware applications as well as laboratory or process applications.

Bottled instrument air or nitrogen is recommended. Up to 80 psig may be used without damaging the actuator or valve. Standard actuators are rated at 70°C, with a high temperature version good to 175°C.

With the addition of a DVI (digital valve interface) to translate the timed event signals into the necessary air pulses, air actuators can be automatically switched by a data system, integrator, or controller such as our DVSP (digital valve sequence programmer) or SVI (serial valve interface).

Two position

The recommended method for implementing a two position air actuator requires an MSVA (manifold solenoid valve assembly), a block-mounted pair of 3-way solenoids that sends a pulse of air to switch the actuator from position to position. A position feedback (PFAF), with contact closures in both positions, is also available as an option.

Multiposition

Multiposition air actuators can be stepped with air from a single 4-way solenoid. A rotary switch on the actuator supplies position information to accessories such as our EPI (electric position indicator), which provides an LED display, or our MCM (multiposition control module). An optional BCD encoder board can translate the position information into BCD code for computer monitoring of valve positioning.

Multiposition air actuated valves can be automated by an MCM (multiposition control module), which provides a method for positioning the valve and transmitting the valve position to an external data system. The MCM allows the valve to be advanced manually with a pushbutton or automatically by a controller or data system with a contact closure or logic level signal. The SSM (stream selection module), used in conjunction with the MCM, allows selected positions to be bypassed.

Electric actuation

The microelectric actuator (two position and multiposition) features automatic valve alignment, high-speed switching, compact size, reversible direction (in the multiposition model), an RS-232 interface, and 24 VDC power input.

If lower cost outranks those factors in your consideration, our standard electric actuator (two position and multiposition) offers a dependable, economical solution. Both types of electric actuators can be operated manually with a controller assembly that features position-indicating LEDs and a toggle switch, but one of the biggest advantages of electric actuators over air is the ease with which they can be connected to an external data system for fully automated control.

Valco’s DVSP (digital valve sequence programmer) can provide timed event sequences, but most users tie the actuators directly into a laboratory computer. Cables are supplied for control by contact closure or logic level signals. The microelectric actuator has built-in multidrop RS-232 (RS-485 optional) for bidirectional communications. The SVI (serial valve interface) was designed specifically to interface our standard electric actuators with RS-232 compatible systems, allowing control of up to six actuators via modem, BASIC program, or Valco-supplied PC software.

Standoff assemblies

All valves, no matter what their actuation mode, can be ordered with a standoff assembly. The standoff is an extension shaft mounted between the handle or actuator and the valve, allowing the valve to be installed within a heated zone while the actuator or handle remains outside at ambient temperature. The standoff extends through the oven wall, and is secured by a clamp ring supplied with the assembly. Standard standoff assembly lengths are 2", 3", 4", and 6". Other lengths can be special-ordered at additional cost.

Right angle drive

Some installations don’t allow the valve and actuator to be installed in a typical in-line configuration. The RAD (right angle drive) is a 90° gearbox which permits the actuator or handle to be installed at a right angle to the valve. The RAD fits all VICI electric and air actuators

Further reference
About mounting hardware

Home | PRODUCTS | Search | Catalog | Contact VICI Prices in USD > Aud Plus Import Freight + 10% GST