How Does a Gate Valve work?

Valves are specially designed devices, which assist in stopping, allowing or speeding up the flow of liquid in a pipeline. As far as gate valves are concerned, these are more suited for completely stopping or starting the flow of the medium in the pipeline. The valve pipeline diameter and gate have the same opening. It makes sure that once the gate valve opens; there is no obstruction to the flow of the liquid.

How does a gate valve function?

The gate valve functions by lifting the rectangular/circular gate out of the path of the liquid in the pipeline. Once the valve opens fully, gate valves are full bore, which leads to zero obstruction in the flow of the liquid. It is because the valve and the pipeline diameter share the same opening. The bore diameter determines the valve size, an advantage of the full-bore design is that it has minimal friction loss, which saves energy and minimizes the cost of ownership.

What are the Different Designs in a Gate Valve?

There are four different designs for buy gate valves online including a slab gate, wedge valve, knife gate valve, and expanding gate. These have been described below in details:

1.     Slab Gate

These types of valves include a single gate unit, which raises and lowers between two seat rings and used for transporting crude oil and NGL’s.

2.     Expanding Gate

As compared to a slab gate valve, an expanding gate valve has two units, a gate, and a segment. The gate and segment units collapse against each other for separation and travel, when the valve is opened or closed.

3.     Wedge Gate

The wedge gate valves come with a tapered gate comprising of a metal-to-metal sealing. As compared to a slab gate or expanding gate valve, the wedge gate valve is not piggable owing to the void left at the bottom of the valve body when the valve is open. The gate then retracts into the valve body when opened; it saves the height space required in the slab and expanding gate valves.

4.     Knife Gate

The knife gate valve is useful in cutting through the extremely thick liquid and dry bulk solid. The design of the valve makes it the best option in self-cleaning as the knife is cleared from any abrasives with every stroke when passing the seat ring and skirts. The gate unit is thin as compared to other gate valve types, and guided by the water-type body. It is one of the best gate valves for easily removing any thick liquid from the pipeline.

What is the Stem in a Gate Valve?

The gate valves can have either a rising or non-rising stem design. The rising stem design offers a visual indicator of the valve position and is attached directly to the gate. On the other hand, non-rising stem designs come with a pointer threaded onto the top for indicating the position and threaded into the upper part for the gate.

The non-rising stem designs are normally suited for applications suffering from limited vertical space. The gate valves designs have a sealing unit for providing a tight seal around the stem.

What Are the Application Areas of Gate Valve?

Owing to the various construction material used in the making of a gate valve, these are highly useful in coking units to food and pharmaceutical companies. Also, these are the standard choice for applications including steam distribution in industrial power plants.