What is a side entry ball valve?
The side entry ball valve is a valve in which a ball is assembled from the inner part. The assembly is usually in three or two piece body. Each piece is assembled by use of a stud or bolt similar to joining two flange pieces. These valves are produced from forge metal. Each part of the body is forged and then they are assembled. Such construction helps to reduce defects that arise from casted valves. These valves are easy to assemble as components are easy to align. Side entry ball valves are the most widely used ball valves.
A side entry ball valve is designed to enhance high performance and it has a robust design as per international standards. Side entry ball valves contain metal soft or composite seats which can be configured with either double or single piston effect to enhance double block and bleed in both closed and open positions. Side entry ball valve manufacturers make the valves with forgings and independent bellows or springs loaded floating seats that are always kept in contact with the ball. This makes the valves a preferred choice for various demands such as cryogenic, low emission, high temperatures, crude oil, natural gas, transmission lines, transmission pipelines, measuring stations, compression, reinjection, and pumping units among others.
Figure: Side entry ball valve
How does a side entry ball valve work?
Side entry ball valve manufacturers make the valve with a spherical closing unit that helps in on/off flow control. The spherical unit has a bore through its center. When in the open position, a valve is kept in a position that aligns the bore or port to the pipeline direction. This allows fluid to flow through it. When you rotate this valve for an angle of 90o, the port becomes normal to the path of flow which closes the valve and prevents fluid flow. Inside the side entry ball valve, the most common design is the one that uses the two-way design. This helps the fluid to flow linearly from the entry to the exit. Side entry ball valves have been known to have a long service life and reliable seal even if the seal is not used for a long time. Side entry valves are known to tolerate contaminated fluid better compared to other valves. These valves have also been used to control fluid flow rate. However, the use of this valve to control fluid flow rate is not common because accurate control of fluid is not easy.
Types of side entry ball valves
Soft seated side entry ball valve
This is a side entry valve ball classified based on seat material. In this type of side entry ball valve, a non-metallic soft material is used to cover most applications. These valves are made using thermoplastic materials such as NBR, PTFE among others. A side entry ball valve made of these materials can easily be damaged when abrasive media or high temperature or high-pressure fluid is used. In soft seated side entry ball valve, elastomeric or thermoplastic seats are fixed in a metallic seat ring or holder. This helps to provide soft seat action in the valve. The key features of a soft seated side entry ball valve are:
- Offers a good sealing.
- Limited operating temperatures.
- Cheaper compared to metallic seated valves.
- Uses soft seat materials which are nylon, PTFE, Devlon, PEEK among others.
- Not suitable for use in dirty services to avoid its damage.
Metal seated side entry ball valve
These side entry ball valves are made of metallic materials like 316 SS, Monel among others. Side entry ball valves made of these materials are known for zero jamming, tight shut-off, wear resistance, good corrosion, and smooth control, a wide range of temperature, wear resistance, good stability under pressure among others.
The key features of a metallic-seated side entry ball valve are:
- There is direct metallic contact between the ball and seat ring.
- They are suitable for abrasive applications and cases where soft-seated valves cannot be damaged by the temperature.
- They can accept leakages according to ISO 5208 rate D.
- The seat and ball contact surfaces are hardened to enhance wear resistance and scratching that arises from solid materials contained in the fluid.
- Metallic seats rarely bend easily relative to soft seats under pressure.
Two-piece side entry ball valve
This is a side entry ball valve made in two pieces where the ball is held in its position using a stud. This type of side entry ball valve can have a reduced bore or full bore design.
Three-piece side entry ball valve
This is a side entry ball valve that has one centerpiece and two end pieces. This type of side entry ball valve is mostly online maintainable. When the body bolts are removed and only one is kept, the body can easily be swung away by use of the last bolt as a fulcrum which helps to do any maintenance or installation on the valve. This helps to reduce the time taken on maintenance.
Floating side entry ball valve
These side entry ball valves are also known as seat-supported side entry ball valves. These valves have the following main features:
- The ball is not held rigidly on the rotational axis and it floats freely between seat rings.
- While in closing position the ball is pushed on the seat by fluid pressure from upwards and thus pressures the seal downwards of the valve.
- Metallic seated side entry ball valves also have spring-loaded seats.
- The floating side entry ball valve requires high operating torque.
- Floating side entry ball valves are cheaper to manufacture.
Trunnion mounted side entry ball valve
The main features of this type of side entry ball valve are:
- The valve seat is loaded on the ball using a spring which offers a reliable seal at low pressure.
- The ball is mounted on its position using Trunnion and steam that are supported in bearings on the valve body.
- The main feature of the trunnion mounted side entry ball valve is that it cannot shift to press the ball as it happens in the floating side entry ball valve rather its line pressure pushes the upstream seat on the ball which causes a seal.
- Side entry ball valves of this type are of higher pressure ratings and larger sizes.
- The area where the pressure acts is small. This makes the exerted force on the ball very small which results in lower friction force and thus smaller gearbox or actuator.
- Trunnion mounted side entry ball valves are designed with self-reliving seats.
Components of side entry ball valve
This is the major component of the side entry ball valve and it contains all the internal parts for enhancing on and off operations of the valve.
This is a ball that has a center hole through which the fluid flows. This gives the primary characteristic that differentiates between the ball valve and other types of valves. Through one axis, the ball hole connects the valve inlet and outlet.
This is the part of the side entry ball valve that helps to connect the ball to the outside control mechanism. Stem helps to control ball direction.
These are discs lying in between the body and the ball. They provide the necessary seal between body and ball as well as support the ball.
The source of power in a side entry ball valve could be a manual actuator or automatic actuator. For manual power, actuation is done via handles and levers that are used by the operator during on and off operation to control flow. An automatic actuator uses a pneumatic, electric, or hydraulic power source. The power is responsible for providing energy to the stem to rotate the ball and thus control flow.
This is a seal placed around the stem to ensure no fluid escapes.
This is the component of the side entry ball valve that contains the packing and stem.
Specifications when you need to purchase side entry ball valve
The specifications needed by the manufacturer or vendor when purchasing a side entry ball valve are:
- Size and pressure rating of the side entry ball valve.
- Ball-type that is trunnion or floating mounted design.
- Type of the bore that is reduced or full bore.
- Sealant injection system requirements.
- Locking device needed.
- Anti-static device
- The operating mechanism that is gear, lever, or actuator (pneumatic, electric, or hydraulic).
- Materials of the seal rings, valve body, trunnion. Seals, trim, bolts, nuts, gaskets, and packing.
- Orientation of the valve.
- Painting details if necessary.
- Seating type that is metal or soft seated
Applications of side entry ball valve
- Side entry ball valves are used in refineries. These valves have been used for isolation and shut-off of thermal cracking units and tower bottom lines, oil and gas separation lines, measuring of gas distribution, pressure regulation, and metering, oil loading control, compressor and pumping stations, refining units among others.
- The side entry ball valve is used in petrochemical and chemical complexes for controlling low differential pressure, controlling emissions, handling high viscous fluids, control the flow of abrasive slurries among others.
- Side entry ball valves are used in power generation. These valves are used to control boiler feed water, to control and turn off steam, among others.
- They are used in the production of oil and gas. Side entry ball valves are used in shut-down facilities, control of pipeline serge, and isolation of oil-head, storage, processing separation, distribution, and transmission among others.
- They are used in the paper and pulp industries. Side entry ball valves have been used as shut-off valves, control of liquor circulation and fill, control of lime mud, control of dilution water, control flow in mill digesters in pulp production among others.
- Side entry ball valves are used to control water transport.
- They are used in the control of solids in marine transport.
- They are used in the food and beverages industries.
Advantages of side entry ball valve
- Side entry ball valves employ a simple design.
- These valves are of small weight and volume relative to other valves.
- Side entry ball valves are easy to disassemble and repair.
- Side entry ball valves are easy and quick to operate.
- These valves rotate without axial motion which makes it hard for the valve stem seal to get damaged.
- These valves provide perfect sealing.
- These valves can provide low-pressure drop and high flow rates.
- Side entry ball valves open and close quickly.
- Side entry ball valves rotate 90 degrees to close or open. In emergency cases that need quick insulation of the pipeline, closing and opening the valve can be done very quickly.
- Side entry ball valves are bubble-tight.
- These valves can be used in slurry and clean applications.
- There are varieties of side entry ball valves that can be used in high-temperature and high-pressure applications.
Disadvantages of side entry ball valve
- The side entry ball valve is not suited for sustained throttling.
- When used in slurry applications, suspended solids can settle and when trapped in the body cause wear and leakage and finally valve failure.
Troubleshooting side entry ball valve
Leakage at the socket connection
- It could be due to improper threads. Check the size of threads and replace or install.
- Due to thread joint being over-tightened thus splitting connector. Replace the cracked end connector.
- Improper thread sealant used. Reinstall thread connection as per the recommended procedures and check compatibility with the paste/sealant.
Leakage at the union nuts
- Misalignment of end connector. Check alignment of the system. End connectors need to be parallel. Ensure there is enough valve support.
- Union nut is loose; tighten it.
- Damaged or displaced O-ring. There are particles in the groove of the O-ring. Remove valve for O-ring inspection to check for chemical or physical damage. Also, check for O-ring compatibility and replace if necessary. Clean the ring accordingly.
- Stem O-ring is damaged. Disassemble valve stem and inspect for chemical or physical damage. Also, check O-ring compatibility. Clean the O-ring and replace it if necessary.
- The ball is obstructed. Verify if the ball is in its recommended full-closed position. Otherwise, remove the side entry ball valve to check for particles that could be blocking the ball bore. Clean it and reinstall.
- The stem is broken. Remove the end connector and verify the ball can rotate while you operate the valve. Replace it if necessary.
- Damaged PTFE seat or debris-laden. Disassemble valve seat. Check physical damage and excessive debris. Clean it and replace it if necessary.
- Seat O-ring damaged, displaced, or debris-laden. Disassemble seat O-ring and check for chemical or physical damage. Ensure there is O-ring chemical compatibility. Clean the ring and replace it if necessary.
- Damaged ball. Remove and disassemble the side entry ball valve. Check if it has physical damage that is nicks, scoring on the seat sealing surface. Clean the seat surface and replace the ball if necessary. Ascertain chemical compatibility with valve material (CPVC, PVC, etc.) and check chemical damage.
- Thermal damage causing distortion of components. Check operating temperature, heat from external sources, and heat produced from system design.
This is the case where the valve is difficult to close/open accompanied by stem shear break. The probable causes and solutions are:
- Internal obstructions; build-up of particles or sediments; solvent cement accumulating on the ball. Remove the side entry ball valve to check for debris, solids, or cement deposits blocking the valve interior or ball. Check if sediment solids are lodged on the ball-to-seat areas. Check the same for the stem and clean and reinstall where necessary.
- Broken handle. It could be due to external impact or frozen movements. Identify, correct or replace where necessary.
- The stem broke/sheared. It could be due to external impact or frozen movements. Replace accordingly.
- Stripped handle. It could be due to excess exposure to sunlight making it softer or overextending close/open range. Shield valve from direct sunlight and replace if necessary.
- Broken body. Excess internal pressure or due to external impact. Verify the source and check surge pressure and system pressure.
The side entry ball valve is a ball valve whereby a ball is assembled from the inner part. Side entry ball valves are assembled in two or three pieces. Each piece of assembly uses bolts or studs similar to how two flange pieces are joined.
Side entry ball valves are made from forge metal to help reduce defects that occur when the valve is made by casting. Using studs to assemble the pieces of side entry ball valves makes it easy to align. These valves are manufactured using composite or metal seats configured with a single or double piston effect that enhance double blocks and bleeds in open and closed positions.
These valves are used in various applications such as low emissions, cryogenic, crude oil, high temperatures, crude oil, natural gas, transmission pipelines, transmission lines, measuring stations, pumping, and compression reinjection among others. The side entry ball valves find many applications because of their many advantages such as simple design, small weight, and volume, easy to disassemble and repair, quick operation, offers bubble-tight seal, among others.