API 600 gate valve is a bidirectional valve you can use to open and close flow in the pipelines. They come in different features and properties while conforming to the API 600 standards.
Why API 600 Gate Standard is Critical
The valve design and construction criteria are specified as well as materials and trim designated. Usually, it covers information about the pressure seal valves. Ideally, you will find these valves with heavier walls to help prevent corrosion.
It also has important dimensions such as stem diameter, minimum wall thickness, and stuffing box size.
API 600 Gate valve Advantages.
- Gate valves are bidirectional and hence they can utilized in two directions.
- It has good shutoff features.
- API 600 gate valve works with efficiency with viscous fluids.
- They are long-lasting and durable. The materials used in manufacturing API 600 gate valves are strong and long-lasting.
- API 600 gate valve parts are easy to assemble, repair, and maintain.
API 600 Gate Valve Classification
· With Knife Gate
These types of gate valves are mainly used for highly viscous fluids. They help to eliminate the water hammer effects by opening and closing at a very low speed. Knife gate is made with materials like ductile iron and stainless steel. Usually, they are available in different sizes ranging from 2 inches to 24 inches.
API 600 gate valve with knife gate has major limitations in that it has a low-pressure rating. It has different variants like the soft seat, the metal seat, and the bonnet type.
Rising and Non-rising Stem API 600 Gate Valve
In the rising stem gate valve, the stem rises above the handwheel and the valve is opened while on the hand in the non-rising stem.
You will realize that the stem does not rise above the hand wheel. Due to this trait, manufacturers have developed indicators for the non-rising stem. It tells its operator when the valve is opening or closing.
The rising stem gate valve requires large installation space because of its stem. On the other hand, the height of non rising stem gate valve is small thus much space during installation.
API Gate Valve with Expanding Gate
This type of gate valve is designed with wedge gates and segments. You will mostly use these valves with highly abrasive liquids under high temperatures and pressure.
Positive sealing is achieved through mechanical expansion of the gate and segments against the seal.
When the stem exerts a thrust on them, it causes expansion of the gate and segments occur.
In both open and closed positions, expansion creates a tight seal against the upward stream and downstream sides which helps to prevent wear of the seat and gate.
Parts of API 600 Gate Valve
· Body and Bonnet
Body and bonnet have uniform sections and radius fillets to prevent stress concentration. The gate valve body has a straight-through port without any recessed except at the seating area to ensure minimum flow erosion and resistance to flow.
The bonnet has an accurate a liniment of stem and smooth operation due to the casting of one piece designed where the yoke is integral with the bonnet gate valves.
· Stuffing Box
The stuffing box has a flat bottom that allows correct sealing of the gland packing. The stuffing box is provided with five numbers of gland packing. Usually, this achieves correct compressions of all packings and ensures tight sealing.
· Seat Ring
The seat ring has a feature of seal-welded seat ring. It offers a leakproof design. This eliminates the leakage path between the seat rings and the body.
The stem has a one-piece construction, threaded and precision-machined with a polish surface to reduce friction.
It helps in the control of fluids through the valve.
API 600 Gate Valve Design and Construction
API 600 gate valve varies depending on the end connection, bonnet wedge, stem, or valve operation.
There are two types of gate valves – wedge-shaped and parallel-shaped. The wedge shape can either be classified as flexible wedge, spilted wedge gate, or solid taper wedge gate.
Besides, the wedge disk is usually fully guided to ensure tight sealing. There are different designs including rising and non-rising stems, knife, slabs, and expanding. In most cases, there are many mounting options.
Steel is used to manufacture solid wedge gates. The design of the flexible wedge helps to adjust to the changes in the angle between the seats.
Parallel gates have a flat gate placed in a perpendicular position to help the flow of liquids between parallel seats.
The stem can be designed either as a rising or non-rising. A rising stem rises above the handwheel when the valve is opened. On the other hand non-rising stem does not rise above the handwheel when the valve is opened.
Usually, the valve of an API 600 gate valve can be designed operation either manual, gear, pneumatic, electric, or hydraulic actuation.
How API 600 Gate Valve Works
API 600gate valve works by inserting the disk into the pipeline, sealing it when closed, and lifting it out of the way when opened.
This barrier can be raised or lowered via a handwheel on the valve bonnet.
When the API 600 gate valve handwheel is rotated in an anti-clockwise direction the vertical movements of the stem cause the gate to open.
On the other hand, when rotated in a clockwise direction causes the gate to move downwards making the gate close.
These API 600 gate valves a hand hand-wheel operated. Normally, the isolation valve whose actuation system might be connected to either the rising stem valve or non-rising stem valve design.
Operating the gate valve when opened may cause a huge loss of pressure. Whenever you are using fluids, it must be less corrosive. Such fluids leave sediments that may prevent the gate from closing fully.
API 600 Gate Valve Troubleshooting
Troubleshooting is the tracing and correcting of faults in a mechanical or electronic system.
· The Operation Nut is not Turning in Either Direction
This can be caused by any interference between the valve box and the operating key. Check for any kind of interference in the valve box and if it’s there ensure you reposition it.
The operating nut not turning in either direction can be caused by the stuffing box bolts and nuts unevenly tightening during assembly. Check and loosen or evenly retighten the stuffing box bolts and nuts.
Operating nuts not turning in either direction can be caused by erosion that might have taken place in the stuffing box and stem. Replace both the stuffing box and stem and ensure to clean if necessary.
The formation of debris under the gate can lead to the operating nut not turning in either direction. Remove the bonnet and clean the debris.
Getting the Wrong Number of Turns when Closing the API 600 Gate Valve
This can be caused by debris accumulating in the seating. To get rid of the debris ensure to create a flow through the valve and exercise the valve to get rid of debris.
Operating Nits do nonstop Turning even After the Right Number of Turns
This is caused when the operating nut is subjected to exercise torque. Keenly inspect the stem and step nut, then replace the nuts if necessary. Each valve has a gear to help operations. Check if the API 600 gate valve was installed with a gear.
Leakage between Body and Bonnet Flage
Damage O-ring/gasket can cause leakage between the body and bonnet flage. It is caused by mainly cracked or broken body inspection and replacing the body as necessary.
Leakage between the body and bonnet flange may be caused by loose bonnet bolts and nuts. Check and ensure the bonnet bolts and nuts are tightened.
Fluids Leaking from the Stuffing Box Area
When the stuffing box packaging and stem O-ring are worn out they cause fluid leakage from the stuffing box area.
Leakage from the Seat
Leakage from the seat can be caused by a damaged seat. Ensure the seats are replaced to avoid leakage.
It can also be caused by foreign materials that are stuck under the gate. Remove all foreign materials to prevent leakage from the seat.
API 600 Gate Valve Applications
- It is used in chemical industries
- API 600 gate valve is used in Oil and natural gas pipelines
- It used in transportation pipelines and storage equipment for refined oil
- Used in power plant plantation
API 600 gate valves are constructed to the standards of the American Petroleum Institute. It can be used in different applications and has different advantages.