02182018Sun
Last updateFri, 16 Feb 2018 8pm

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Putting Servo Valves Back to Work

Putting Servo Valves Back to Work

Industries as varied as paper production...

Corrosion and Fouling: Is There a Solution?

Corrosion and Fouling: Is There a Solution?

According to a 1998 study released by the ...

Valves with All the Trimmings

Valves with All the Trimmings

The term valve trim has been around for ...

VMA Chair Mark Nahorski: Industry Has Many Pathways to Success

VMA Chair Mark Nahorski: Industry Has Many Pathways to Success

Part of the discussion today about what ...

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Industry Headlines

ValvTechnologies ITC 2018 Recap

Friday, 16 February 2018  |  Chris Guy

The biennial ValvTechnologies’ International Technical Conference and Users Group (ITC) was held on February 8-9 in Houston. Seeking to educate,...

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Putting Servo Valves Back to Work

Putting Servo Valves Back to Work

Monday, 12 February 2018  |  Christopher Valiquette

Industries as varied as paper production, steelmaking and power generation rely on servo valves for precise motion control. A servo valve can last wel...

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Industry Headlines

ValvTechnologies ITC 2018 Recap

1 DAY AGO

The biennial ValvTechnologies’ International Technical Conference and Users Group (ITC) was held on February 8-9 in Houston. Seeking to educate, inspire and engage attendees over a two-day period, the event brought together hundreds of attendees from across the globe to share valuable insight ...

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Matthew Davis Named Field Service Manager at Weir

2 DAYS AGO

Weir Valves & Controls USA (WVC USA) has appointed Matthew Davis to the position of field service manager. In his new role, Davis will be responsible for managing the WVC USA Field Service crew and organizing WVC Service jobs for power plants worldwide.

Davis joins WVC USA with over 20 years of ex...

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TransCanada Turns Attention to Natural Gas System

2 DAYS AGO

TransCanada Corp. will move forward with a $1.9 billion expansion of its NGTL System to connect incremental supply and expand basin export capacity by one billion cubic feet of natural gas per day at the interconnection with its Canadian Mainline. NGTL expects to begin construction in 2019.

The increme...

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U.S. Oil Output Surge Reminiscent of Run-Up to 2014 Dive

4 DAYS AGO

According to the International Energy Agency (IEA), fast rising production in non-OPEC countries, led by the U.S., is likely to grow by more than demand in 2018. For now, the upward momentum that drove the price of Brent crude oil to $70/bbl has stalled; partly due to investors taking profits, but a...

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U.S. Industrial Production Fell 0.1% in January

2 DAYS AGO

Industrial production edged down 0.1% in January following four consecutive monthly increases. At 107.2% of its 2012 average, total industrial production was 3.7% higher in January than it was a year earlier.

Manufacturing output was unchanged in January for a second consecutive month; the index has i...

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U.S Business Inventories Rose 0.4% in December

2 DAYS AGO

Manufacturers’ and trade inventories, adjusted for seasonal variations but not for price changes, were estimated at an end-of-month level of $1,902.2 billion, up 0.4% from November 2017 and were up 3.2% from December 2016.

A poll of economists “had forecast inventories, a key component of...

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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.

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