Stainless Steel 316? Carbon? Ceramic? Selecting the right material of construction for your pump or valve is a tough call, especially if you're considering total cost of ownership (TCO). It's a known fact that maintenance costs account for more than 50% of process equipment's TCO. All too often we see operators select materials of construction purely based on cost, an expensive choice considering not every material holds up in all applications.
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In this post, we'll talk about the pitfalls of choosing the wrong materials of construction for pumps and valves and what factors you should consider when selecting suitable materials.
Using the wrong materials of construction can (and will) lead to premature degradation, corrosion, fluid contamination, excessive wear, and leaks. Selecting a casing for a pump that cannot withstand abrasive fluid will wear faster and increase clearances, drastically reducing the performance of the pump. In a previous post, we talked about the importance of proper material selection for mechanical seals. If the wrong materials are chosen, an operator risks mechanical seal failure. The same goes with pumps, even valves.
UNDERSTAND THE FLUID'S NATURE AND COMPOSITION
Assess the fluid's pH levels, aeration impurities, chemical additions, suspended solids, etc. Understanding the fluid, and investing in the right materials initially is the right move to ensure the pump or valve will function properly throughout its lifetime.
FLUID TEMPERATURE AND PRESSURE
Make sure to take note of the fluid's temperature and pressure ranges (minimum and maximum), and if any thermal shocks are present in the fluid.
FACTOR IN FLOW AND VELOCITY
Is flow continuous, intermittent, or standby? What is the velocity of the fluid?
EQUIPMENT REQUIREMENTS
Think about the equipment's reliability expectations. What is the minimum life expectancy? Is this a piece of equipment that can easily and affordably be maintained or repaired if need be? If it's a critical component, the need for the highest quality materials may outweigh the need to save money on the purchase price.
EXAMPLE: CAST IRON VS. STAINLESS STEEL
Cast iron is generally the least expensive option when it comes to material selection for rotating elements and casings. But, buyer beware. While cast iron is abrasion resistant, it does not have strong corrosion resistant properties. Stainless steel, however, is a common choice for its corrosion resistance properties and has become a universally popular material choice for pumps and valves. Please note: There are different grades of stainless steel available today, so careful consideration should be taken to ensure longevity and cost effectiveness.
Material selection for process equipment isn't an exact science, but understanding the fluid's characteristics can help you make an educated decision about what materials are right for the application to avoid unnecessary maintenance costs and downtime. Selecting the right materials of construction is just one step towards increasing pump reliability and minimizing total cost of ownership.
4-step Guide to Choose the Right Valve for your Industrial Application
Choosing the correct components for your industrial fluid systems is imperative to ensure long-term performance. Valves are one of the most significant components to consider. With the right pumps, operators can implement these controls to control system fluid flow according to the application’s requirements.
Why do we need valves?
Choosing the right valve begins with determining the purpose of the valve. Valves may be used for a range of tasks and accomplish a variety of functions. When selecting any valve for industrial usage, the best place to start is by determining what purpose it will serve.
Some of the things to consider might be:
- What will it be used for? Controlling or isolating media?
- Will it be utilised several times each minute or only once every several months for maintenance?
- How important is it to your process, and what happens if it fails?
- Is it a valve that must function in an emergency?
This will make choosing the proper valve for the job much easier. Once you decide the type of valve you require for your purpose, many industrial valve manufacturers in India offer high-quality valves.
In this post, we will discuss the four factors to consider when choosing the proper valve for your industrial application:
1. Valve size and type
Choose the correct valve type. Each valve performs one or more essential functions:
- Shut-off flow – Control the flow of hazardous fluids safely (liquids, gases, slurries, and fluidised solids) by securely halting or resuming fluid flow.
- Divert flow – Divert the flow of bulk solids from one feeding point to two or more receiving points.
- Mix flow – Mix and regulate concentrations such as water temperature for HVAC and crucial process and cleaning applications.
- Pressure relief – Improve safety by returning a system to the desired pressure during over-pressure events.
- Backflow prevention – Allow the valve to open automatically when media flows in the desired direction and close automatically when the flow reverses.
- Adjust flow – Adjust and control air volume flow within a pneumatic system to ultimately control the speed of operation of an actuator.
Function determines the design of standard valve types. Among the most common valve types are:
Ball valve:
A ball valve is a shutoff valve that lets liquids or gases flow through a rotary ball with a bore. A quarter turn (90 degrees) around the ball’s axis allows the medium to flow through or be blocked.
Ball valves are the best gas used because they provide superior sealing. They can withstand pressures of up to 700 bar and temperatures of up to 200°C, and their diameters generally range from 0.5 cm to 30 cm. Because of their basic construction, they are simple to operate and maintain.
Applications
- Flow and pressure control and shut off for corrosive fluids, slurries, regular liquids, and gases.
- Used primarily in the oil and natural gas industries and various manufacturing sectors, chemical storage, and even residential applications.
Butterfly Valve:
Butterfly valves stop, regulate, and start flow with a quarter-turn rotational motion. 90° rotation of the handle closes or opens the valve completely.
Butterfly valves are advantageous over the gate, globe, plug, and ball valves, particularly for large valves. Suitable for handling high volumes of liquids or gases, slurries, and liquids containing large amounts of suspended solids.
Applications
Water supply, wastewater treatment, fire prevention, gas supply, chemical and oil industries, fuel handling systems, power generation, and so on.
IDEX India offers butterfly valves in versatile configurations for efficiency, durability & long-lasting performance.
Grande Precision Machinery contains other products and information you need, so please check it out.
Globe Valve:
A globe valve is a type of valve used for regulating flow in a pipeline, which is different from a ball valve. Globe valves consist of a movable plug or disc element and a stationary ring seat.
They are ideal for regulating clean liquids, gases, and inert and corrosive media.
Applications
- Cooling water systems.
- Fuel oil systems.
- Feedwater or chemical feed systems.
- Boiler and main steam vents and drains.
- Turbine lube oil system and others.
Safety valves:
Safety valves are used to prevent overpressure in a system. They control pressure increases, leading to malfunctions, fire hazards, or explosions. They are used when electronic, and pneumatic safety devices fail because they only contain mechanical parts.
Applications:
- Used in the oil, gas, and petroleum industries to discharge hazardous substances.
- Used in the energy sector to discharge overpressure in steam, air, gas, or liquid pipelines, or vessels/boilers
Sleeved plug valve:
A sleeved plug valve is used for on/off and throttling service in demanding process applications with media temperatures as low as -20°F to as high as 600°F.
With an innovative stem seal design made of cup springs, the IDEX plug valves ensure uniform force distribution, resulting in no emissions and an enhanced life cycle.
Richter Sleeved Plug Valves are precisely designed to ensure lower and consistent operating torques, which helps smoother and hassle-free operations.
Applications:
Used for throttling applications in petroleum, chemical, pharmaceutical, chemical fertiliser and electric power industries.
Lining Plug Valve:
Lined plug valves have a polymer coating inside the valve. The valve has a body, plug, seat, and stem extending outside the body to connect with the handle.
The plug raises and lowers the valve. As the stem is reduced, the plug is lowered into the plug seat.
Aside from being non-lubricated, the lined plug valve features a Teflon-lined body and plug. This feature protects the valve against corrosion caused by chemical fluid.
Applications:
- Cementing, coiled tubing, high-temperature materials, and acidizing require high-pressure flow lines.
- Most upstream applications choose lubricated plug valves because they do not clog and are safe to use with corrosive chemicals.
- Flow control/isolation entails separating the liquids in the pipes to avoid contamination.
2. Materials of construction
Know the chemical compatibility requirements. The valve materials should be compatible with the gases and liquids it is intended to handle. Typically, plastic valves are more resistant to harsh chemicals than metal valves.
- Cast Iron – Cast Iron body is mostly utilised for low-pressure and low-temperature applications.
- Ductile Cast Iron – Because of its wide range of operating temperatures and pressures, this is extensively used in steam, water, gas, and oil pipeline systems. It provides excellent value for money.
- Stainless Steel – This material is widely utilised in a variety of applications, ranging from the petrochemical sector to general plant systems, because of its exceptional corrosion resistance and durability.
- Special Alloy Steel – This metal offers the highest corrosion and pitting corrosion resistance.
- Bronze – Bronze is great for complicated castings due to its high wear resistance, corrosion resistance, and machinability. It is also appropriate for valves used in low to medium pressure service.
- Brass – This copper and zinc alloy has better forgeability and machinability than bronze and is less expensive.
- Cast Iron Lining – The inner and exterior sides of an iron valve are powder-coated with Nylon 11 and epoxy resin, resulting in a lining that prevents red, rusty water. It can also be used in drinking water supply lines.
- Cast Steel – Cast steel is often used for pipelines in oil fields, refineries, and petrochemical facilities due to its wide range of working temperatures and pressures.
3. Performance requirements
Determine the pressure and temperature requirements. Find out the temperature and pressure ranges where the valve will be installed. Metal valves tend to withstand higher temperatures and pressures than plastic valves.
For pressurised gases, metal valves are also best. That’s because metal valves are generally stronger than plastic ones.
4. Safety First
It is not uncommon for fluid systems to be operated at high pressures and temperatures. If a leak occurs, hazardous materials may leak and pose a threat to the operators. To prevent unnecessary hazards, fluid systems should be installed and operated according to best practices.
A valve’s role is critical to a fluid system’s safe operation. For instance, a safety or pressure relief valve can prevent your system from over-pressurising, a potentially hazardous scenario that could cause a blowout. This is why choosing the suitable valve for a particular function is crucial.
In almost all processes and systems, valves regulate gas and liquid flow. Choosing the right valve can often be tricky, no matter how common they are. The first step in selecting a valve is identifying the system performance requirements. Once you know what you need, choosing the right valve becomes easier.
We at IDEX India are well-versed in various valve applications and can provide you with expert advice. With customised valving solutions, we can meet your unique application requirements.
Are you interested in learning more about Pump and Valve Castings? Contact us today to secure an expert consultation!
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