Gear Valve – Gear Operated Gate Valve

Description

Gear valves regulate the flow of liquid or gas.

What is a Gear Valve?

Gear valves are the more complex of the two manual operators. Their installation and operation usually require more effort than lever operated valves. Most gear valves have worm gears that make them easier to open and close. This means that the majority of gear valves can fully open or close with only a few turns.

How to use a Gear Valve?

The main quality that sets gear-operated valves apart is the way in which it is operated. This type of valve requires manual operation. Gear-operated valves regulate the flow of liquid or gas. This involves the operation of a wheel moving a disc that holds or releases the liquid or gas through a system. This is hand-operated, making it simple to control the flow whenever you want.

Typically, manual operators, such as gear-operated valves, are inexpensive. These valves are a good choice for high-stress environments and small spaces. Though gear-operated valves are a little more complex than other manually operated valves, most can open or close with a few simple turns. However, with some applications, this can become tiresome over time.

Applications of Gear Operated Valve

Gear operated valves are usually used in high-stress & big size situations.

What is a Gear Operated Gate Valve?

ZECO gear operated gate valve is defined according to the driving mode. Gear operated gate valve is mainly used for large-diameter gate valves. Because of the large torque, it is almost impossible to open the valve by manual operation. ZECO, as a Chinese manufacturer of gear operated gate valves, can design and manufacture the gear units to be waterproof for outdoor use according to customers’ requirements.ZECO gear operated gate valve is available in carbon steel series, stainless steel series, alloy steel series, and low-temperature steel series. As an expert in industrial pipeline valve solutions, ZECO specializes in designing and manufacturing industrial valves to assure customers of quality.

Features of Gear Operated Gate Valve

• ZECO gear operated gate valve adopts the top-mounted stem nut design, because of the corrosion situation outdoors, the handwheel is probably the easiest to corrosion damage parts, and in replacing the handwheel, ZECO design can ensure the stem and disc in the condition of the open valve, even can’t fall off the handwheel, ensure the valve in the pipeline in the process of maintaining the normal use;
• The packing of ZECO gear operated gate valve is made of a flexible graphite material, and its sealing performance is very reliable after nearly 30 years of use. But also according to the requirements of the user, the choice of packing ring and grease structure to ensure that the valve stem seal;
• The stem of ZECO gear operated gate valve is connected to the gate by a t-groove, which allows the gate to be automatically corrected and sealed normally if it is offset by medium impact;
• The casting of ZECO gear operated gate valve has been strictly inspected by the inspection department to ensure that all materials can meet international standards and make users feel more assured in use.

What are Different Types of Gear Operated Gate Valves?

There are three ways to classify the gate valve.

Types of Disk

• Solid wedge
  • The solid, or single wedge gate valve is the most widely used and the lowest cost used type in the process industry for oil, gas, and air services. The purpose of the wedge shape is to introduce a high supplementary seating load. Solid-Wedge Gate Valve can be installed in any position, suitable for almost all fluids and practical for turbulent flow services.
• Flexible wedge
  • The Flexible wedge gate valve employs a flexible wedge that is a one-piece disk with a cut around the perimeter (the cut varies in size, shape, and depth). Thermal expansion and contraction entail no problems in such kinds of gate valves as the disk is able to compensate for this and remains easy to open. Flexible wedge gate valves are widely used in steam systems to prevent thermal blinding
• Split wedge or Parallel disks Valve
  • Parallel disk gate valves consist of two discs that are forced apart against parallel seats by a spring at the point of the closure. The most famous type is the knife gate valve which has a flat gate between two parallel seats (an upstream and a downstream seat) to achieve the required shut-off. The application of a parallel gate valve is limited to low pressures and low-pressure drops.

Types of Body Bonnet Joint

• Screwed Bonnet
  • This is the simplest design available and it is used for inexpensive valves.
• Bolted-Bonnet
  • This is the most popular design and is used in a large number of gate valves. This requires a gasket to seal the joint between the body and the bonnet.
• Welded-Bonnet
  • This is a popular design where disassembly is not required. They are lighter in weight than their bolted-bonnet counterparts.
• Pressure-Seal Bonnet
  • This type is used extensively for high-pressure high-temperature applications. The higher the body cavity pressure, the greater the force on the gasket in a pressure-seal valve.

Types of Stem Movement

• Rising Stem or OS & Y Type (Outside Stem and Screw Type)
• Non-rising Stem type

What are the Advantages of Gear Operated Gate Valve?

1. Small flow resistance;
2. Opening and closing torque is small;
3. Can be used in the medium to flow in two directions of the ring network pipeline, that is to say, the flow direction of the medium is not limited;
4. When fully open, the sealing surface is less eroded by the working medium than the globe valve;
5. The body structure is relatively simple, the manufacturing process is better;
6. The structural length is relatively short.

What are the Disadvantages of Gear Operated Gate Valve?

• They cannot be opened and closed quickly. To fully open or close wheel or gearbox actuators, the shaft should be rotated as many as the full open revolution number. The full open revolution number is equal to the pitch
• Assembly, start-up, and maintenance require large space.
• In the fully closed position, the slow movement of the slide causes high flow speed. Due to vibration and collision, abrasion and deformation occur in the seating surfaces and the surface gets damaged from friction.
• In systems where high-temperature changes irregularly, due to the load in the pipe at the valve end, leakages in gate valves occur.
• At the place of operation, repair, and maintenance of seating surfaces are difficult.

Material of Gear Operated Gate Valve

No	Part	Material
1	Body	ASTM A352 LCB
2	Seat Ring	ASTM A182 F304 + STL
3	Wedge	ASTM A352 LCB + STL
4	Stem	ASTM A276 304
5	Bonnet Gasket	Graphite + SS304
6	Bonnet Bolt	ASTM A193 B8
7	Bonnet Nut	ASTM A194 8
8	Bonnet	ASTM A352 LCB
9	Backseat	ASTM A182 304
10	Stem Packing	Reinforced Graphite
11	Gear Actuator	ASTM A352 LCB

Difference Between Gear Operated Valve and Lever Operated Valve

Many customers are not very clear about lever/handle/handwheel operated valve and gear operated valve and do not know when to use lever/handle/handwheel operated valve and when to use gear operated valve. The following are applicable working conditions for them.

Both lever/handle/handwheel operated valve and gear operated valve are valves that require manual operation, they are generally called manual valves, but there are still differences between the two in use.

The handwheel of lever/handle/handwheel operated valve drives disc directly, which opens and closes quickly but is laborious; Gear operated valve drives disc through the gear, which opens and closes slowly but saves effort. Therefore, when the pressure in the pipeline is high, it will be particularly laborious to use lever/handle/handwheel operated valve. At this time, gear operated valve should be selected.