Plug valves are not new inventions—in fact their inception may date back to the Roman times when they were employed in the city's plumbing system. They are no less useful today, and in fact as employed in directional flow systems as well as, in some cases, vacuum systems that create a moderate vacuum. They are used by the petroleum industry, sanitary industry, chemical processing as well as power plants.

As might be expected, plug valve types and styles vary to suit their application. These types and styles include natural gas plug valves, industrial plug valves, oil plug valve, 4-way plug valves, twin seal plug valve, to name a few. Below, you will find information about the various plug valve types and styles.

1. Use the oil plug valve and natural gas plug valve.

2. Applying the twin seal plug valve.

3. Use the 4-way plug valves.

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Use plug valves with oil and natural gas

The plug valves that work well for natural gas and oil are generally lubricated and are the steel plug valve and also brass. This is because the steel and brass resist corrosion. The valves are also simple in that they have an on and off position.

I recommend: Homestead Valve has a selection of plug valves for use with oil and natural gas. American Energy Services is a one of the plug valve suppliers that is also a manufacturer.

Learn about twin seal plug valves

Twin seal plug valves have seating slips that help to improve the seal and they are designed to withstand pressures of 150 to 1500 pounds. The twin seal plug valves are used in pipeline stations as well as terminals, naval and aviation fueling systems.

I recommend: Cameron and Cohen Pipe manufacture twin seal plug valves.

Use 4-way plug valves

4-way plug valves often have silicon seals to help make them more effective. The valves can be actuated either by a wrench or by a handle and worm drive. The 4-way plug valves work best to control what's known as directional flow, and can take the place of more than one 'straightaway' valve.

I recommend: Hy-Lok USA and Flowserve Corporation manufacturer 4-way plug valves that you can use in your business.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  When you buy a plug valve, it's a good idea to match the application with the valve, as you can see from the above information. Should you have any questions about the plug valves, the manufacturers can help. The manufacturer can also explain about plug valve pricing and whether or not discounts are available.

Plug valves, or stop-cock valves, suit a wide range of uses. However, they typically serve low-pressure systems better than high-pressure systems. The body and cover of a plug valve contain a conical or cylindrical plug. The plug seats tightly for complete shut-off, or moves to a full range of positions for regulated flow.

Applications for plug valves are too many to list, but they are common in the petroleum and chemical industries, especially the natural gas plug valve. Industrial plug valves are ideal for both gases and liquids, and they can handle slurries, high volumes and a wide temperature range.

The main variations between plug valves pertain to lubrication and materials. Based on those parameters, here are the types of plug valves:

1. Non-lubricated plug valves are prone to sticking, especially if both seat and plug are metal. Thus, they sometimes include a lifting mechanism.

2. Another type of non-lubricated plug valve employs a smooth, rubbery coating over the plug, which reduces friction when the valve opens.

3. Lubricated plug valves open more easily and wear down more slowly. The lubricant has the added advantage of increasing the integrity of the valve seal.

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Buy from plug valve manufacturers that have wide selections

You'll want to find a valve in the correct size and with correct fittings. You'll also want the most appropriate pressure and temperature ratings. Lastly, a big concern is plug valve cost. Looking to plug valve suppliers with wide selections makes the hunt easier.

I recommend: Swagelok has detailed online catalogs for their plug valves. They have numerous options for their plug valves, including pressure ratings all the way up to 3000 psig. For larger or power-actuated industrial plug valves, Assured Automation is a good place to start.

Buy gas plug valves, an oil plug valve or a large sanitary plug valve

The petroleum and natural gas industries sometimes require more specialized valves. Also, sanitary plug valves have size and actuation requirements that are beyond the range of many sources. Searching manufacturers that concentrate on these industries makes the hunt for these types of plug valves much faster.

I recommend: Cameron carries a range of lubricated and non-lubricated plug valves for the gas and oil industries, many of which are easy to repair. For sanitary applications, Cunico is a quality option.

Repair or replace your plug valves

Check your valves regularly for leaks or corrosion. Planned repairs are much cheaper than sudden breakdowns.

I recommend: Replace or repair your damaged valves promptly. You may need to call a quality company like Schutte & Koerting, which refurbishes valves. Also, Furmanite provides a number of repair services for heavy industrial applications.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Many of the smaller plug valves are simple, quarter-turn valves, but there are also 3-port and even 4-way plug valves to suit an even wider range of applications.

The typical uses for plug valves are innumerable. The plug valve actually came into existence during Roman times and continued to be a valuable part in many industries. However, they're most prevalent in the chemical and petroleum industries. To begin learning about plug valves, it’s important to learn a few key terms. From these plug valves key terms, you can then expand on this information to make better purchasing decisions for your company. The types of valves and related data available within the industry are a great place to start building this knowledge.

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Cylindrical plug valve

The cylindrical plug valve is one of the most common plug valves in the industry. The cylindrical plug is what differentiates a plug valve from a standard valve.

I recommend: Review the plug valve summary available at Oil and Gas Online for further details.

Conically tapered plug valves

The conically tapered plug valve is another of the popular type of plug valve. Most tapered plug valves have a Teflon seat to help prevent leakage.

I recommend: Examine the definition of the tapered plug valve at The Everything Development Company.

3-way plug valve

A 3-way plug valve allows the medium to flow from three different directions but offers a single plug to stop the low in all directions. The 3-way plug valve is common in the paper, pulp, filtration and drying plants. Most 3-way plug valves permit flow in both vertical and horizontal directions.

I recommend: Study the 3-way plug valve primer from XOMOX International for more information on the topic.

Plug valve manifold

A plug valve manifold is essentially the piece of equipment that helps regulate the flow of a given medium into and through the plug valves. The plug valve manifold is an integral part of the overall efficiency of the plug valve.

I recommend: Evaluate the definition of the plug valve manifold from Free Patents Online for more information on the topic.

Plug valve specifications

Any plug valve that's manufactured and sold must meet certain industry specifications. These specifications help protect consumers and give them confidence in the usability of any plug valve.

I recommend: Assess the plug valve specifications information available at Global Spec.

Rectangular, round, diamond and standard ports

The various types of ports available on plug valves are the rectangular, round, diamond and standard ports. The name derivation of each comes from its shape.

I recommend: Review the definitions of the rectangular, round, diamond and standard ports available at Homestead Valve.