Thursday, January 30, 2014

A One-piece, Forged Steel, Metal Seat Valve for Critical Applications

One-piece, forged steel,
metal seated ball valve

For applications that require high pressure, high temperature and high safety, consider a one-piece, forged steel, metal seated ball valve. Until recently, limitations in the forging process restricted the manufacturing of larger valve bodies, but now 1/2" to 4" valves in ASME Classes 900 to 4500 are available.

These valves offer the following advantages: a one-piece forged design; a streamlined flow path eliminating cavitation and pressure drop; seats with no exposure to the flow stream; a body cavity isolated from solids build up and flow and erosion resistance.
Velan Power Ball
Velan Power Ball Diagram

Forged valves offer greater strength and increased toughness for maximum reliability and safety. They have become the first choice of fossil and nuclear power stations, the nuclear navy and for all severe and critical applications in the chemical and hydrocarbon processing industries.

One particular brand is the Velan Power Ball,  highly advanced, patented, forged, one-piece metal-seated valve designed for high-pressure and high-temperature applications in the power generation and process industries. More information on the Velan Power Ball can be found here.

Because these valves are used in the most critical applications, consultation with application engineers and utilizing factory authorized installers is recommended.

Wednesday, January 22, 2014

NEMA Classifications for Electric Actuators

Electric Valve Actuator
Indelac Electric Actuator
Electric actuators, or more specifically, the enclosures for electric actuators, need to be matched to the service in which they will operate. Always consult a qualified valve actuator representative to make sure your electric actuator enclosure meets the service requirements.

The enclosure rating standards are defined by the National Electrical Manufacturers Association (NEMA).

Here are the listings of NEMA Classifications: (you can get from the original document from the NEMA site here.)

Definitions [from NEMA 250-2003]

In Non-Hazardous Locations, the specific enclosure Types, their applications, and the environmental conditions they are designed to protect against, when completely and properly installed, are as follows:

Thursday, January 16, 2014

Some Important Valve Terminology

valve terminologyAccessory: Device(s) mounted on an actuator to complement the actuators’ function, such as positioners, solenoids and limit switches.

Actuator: A pneumatic, electric, hydraulically powered “motor” supplying motion to open or close a valve.

Automated Valve: A valve and actuator package capable of responding to a remote pneumatic or electrical signal.

Tuesday, January 7, 2014

Considerations for Sizing Spring Return Pneumatic Actuators

Pneumatic Actuator
Springs, Piston & Seal 
Sizing direct-acting pneumatic actuators is pretty straightforward. The actuator only has the fixed air supply to energize the actuator. If you have enough actuator torque at a given supply pressure to open and close your valve (plus a safety factor), you're good to go. Spring-return actuators, however, present an additional challenge when sizing.