Valve Magazine

Sun04202014

Last updateThu, 17 Apr 2014 1pm

Tank Cars

Tank Cars

The next time you‘re stopped at a crossing waiting...

Extracting Nutrients, Saving Resources through Livestock Water Recycling

Extracting Nutrients, Saving Resources through Livestock Water Recycling

Giant livestock farms, which can house thousands o...

The Expanding Network of Valves

The Expanding Network of Valves

As industry itself reaches into more and more area...

Valve Packing & Gasket Research and Development Devices

Valve Packing & Gasket Research and Development Devices

The continuous improvement of valve packing techno...

VALVE Magazine Print & Digital

Subscribe spr14

Read
the latest digital edition


Subscribe to the digital edition

Subscribe to the print edition

  • VMA Links

  • Gallery of Valves

Ball Valve Butterfly Valve Check Valve Control Valve Diaphragm Valve Gate Valve Globe Valve Needle Valve Pinch Valve Plug Valve Relief Valve
BUYERS GUIDE 300x80

Sponsored Products

  • ja-news-1
  • ja-news-2
  • ja-news-3
Advertisement

Web Only

Magazine

Tank Cars

Tank Cars

The next time you‘re stopped at a crossing waiting for a mile-long train you thi...

The Expanding Network of Valves

The Expanding Network of Valves

As industry itself reaches into more and more areas of the world, getting the eq...

The Expanding Reach of Plastic Valves

The Expanding Reach of Plastic Valves

Although plastic valves are sometimes seen as a specialty product—a top choice o...

Solenoid Valves

sum11_b2b_solenoid_introSolenoid valves are usually considered an accessory in the process valve industry; however, while there is some truth to this, these accessories are crucial to the proper operation of any system that uses them.

The solenoid valve has many features that need to be considered when creating a specification. Eight specification points should be addressed to correctly choose the right solenoid valve for an application. These specification points are:

  • Type
  • Operation
  • Media
  • Size
  • Pressure
  • Atmosphere
  • Voltage
  • Extras

More information on these eight points is included in this article.


TYPE

sum11_b2b_fig1Figure 1. 2-way solenoid valves used to start and stop the flow of media in a pipe trainThe type of solenoid valve refers to whether that valve is a 2-way, 3-way or 4-way. A 2-way valve (Figure 1) has two port connections-a pressure or input port (port 1) and an outlet port (port 2). These valves are used to stop the flow of a fluid or start the flow of a fluid in a piping configuration. Usually, a 2-way valve is referred to as a 2/2 valve, which means the valve has two ports and two positions. The positions are: 1) on or energized and 2) off or de-energized.

Three-way valves (Figure 2) are those that have three ports-a pressure or inlet port (port 1), a cylinder port (port 2) and an exhaust port (port 3). A 3-way valve’s most common application is for process valve automation. The solenoid valve sends air to a spring return actuator or cylinder, which creates rotational or linear movement to open or close a process valve. In this case, the media is usually compressed air or gas that is creating work, which is where the term “fluid power” is derived. The power of a compressed gas or pressurized liquid is controlled to create mechanical work. Three-way valves are usually referred to as 3/2 valves-they have three ports and two positions.

sum11_b2b_fig2Figure 2. Basic 3- and 4-way valves typically used for process valve automationFour-way valves (Figure 2) can have four or five ports-a pressure or inlet port (port 1), two cylinder ports (ports 2 and 4), and one or two exhaust ports (port 3 and possibly a port 5). The exhaust ports can either have both cylinder ports sharing a common exhaust port or have each cylinder port with its own exhaust port. This valve’s primary use is also for process valve automation. For double-acting or non-spring return actuators and cylinders, a 4-way valve must be used. Air flow in a 4-way valve is more complicated than air flow in some other types. For example:

  • In cases where the valve is de-energized or off: The pressure port to cylinder port 2 is open while cylinder port 4 to exhaust is open.
  • In cases where the valve is energized or on: The pressure port to cylinder port 4 is open while cylinder port 2 to the exhaust is open.

Since the actuator or cylinder does not have a spring on one side, it must rely on fluid power from a 4-way valve to open and close. Four-way valves can be referred to as 4/2 or 5/2 valves, and they can have four or five ports and two positions.

There are other configurations such as the dual solenoid, fail-in-last-position, 3/3, and 5/3 solenoid valves, but explanations are best left for another article.

 

Valve Magazine Digital Edition

SPR14 CVR 160x214Inside the Spring 2014 issue…

• Tank Cars
• DBBS & DIBS
• Shale Gas
• New Globe Standard

CLICK HERE TO REQUEST YOUR
DIGITAL EDITION PREVIEW EMAIL