Focet Valves Private Limited

"FOCET" MAKE needle valve is used to accurately control flow rates of clean gasses or fluids. The adjustments are gradual and smooth for controlling the flow rate, however, they can also be used as a reliable shut-off valve. However, they are generally only used for low flow rates and have a relatively large pressure drop from the inlet to the outlet. Common port sizes for needle valves range from 1/8” up to 2”. The most common application is to control the flow of a gas, like a propane needle valve does.

Needle valves open and close an orifice with a tapered end that raises and lowers with the spin of a handle. Figure 2 shows a needle valve cross sectional view, design, and components. The handle (A) is connected to the plunger, also called a stem (F). When you turn the handle, the plunger moves up or down based on the threads (C). The locking nut (B) prevents it from fully unscrewing. As the plunger moves down, the tapered pointed end (I) comes into contact with the valve seat to fully seal the orifice (H). Often, the valve seat is also tapered. There are various options and sizes available to connect it to a pipe or hose through the port connection (G) on the input and output. The bonnet (D) is connected to the valve housing (E), which can be made out of different materials like brass or stainless steel.

Pressure

Understanding the application requirements for pressure in your system is important for selecting the correct needle valve. Robust needle valves can handle pressure of up to 4,000 to 5,000 psi (275 up to 413 bar) at 100°F (38°C). When higher pressures are required, like for high pressure hydraulic applications, high performance valves are available that can handle up to 10000 psi (689 bar) pressure at 100°F (38°C). Special designs are also available when you need a vacuum needle valve to handle the low pressure.

Port & orifice size

Needle valves are available in a wide range port and orifice sizes. The connection ports can also be male or female ends. Common thread standards used are NPT (National American Pipe Thread), BSP (British Standard Pipe), or metric (ISO standards). The most commonly used needle valves range from 2 to 12 mm or 1/8” to 2”. Ensuring the correct port size and orifice size will ensure efficient flow and system operation with less chances of wear and/or leakage.

Temperature

Needle valves are suitable for high or low temperature applications. You need to specify the valve housing and packing/sealing material appropriately, especially for extreme temperatures, to ensure it can withstand the requirements. The two most common sealing materials are PTFE (Teflon) for a temperature range of -65°F to 450°F (-54° C to 232°C) and PEEK (Polyether Ether Ketone) for increased temperature resistance up to 600°F (315 °C).

Needle valve applications

You will see needle valves across all fluid control applications due to their ability to precisely control flow rates. By selecting the appropriate valve material and size for temperature and pressure, they can be used for almost any clean gas or fluid. One of the most commonly used location for needle valves is to monitor gas flow, like propane, in a system. A propane needle valve can accurately shut it off and/or control the flow rate and effectively the burn rate for applications.

Needle valve symbol

If looking at a schematic, Figure 4 shows a needle valve symbol. It has the standard 2-way valve symbol with an arrow indicating it is a needle valve.

Figure 4: Needle valve symbol

"FOCET" A needle valve is a type of valve that provides precise control over fluid flow. It’s characterized by its long, tapered needle-like plunger, which adjusts the flow rate by varying the size of the orifice through which the fluid passes. Here’s a detailed look at its usage and key aspects:Purpose and Function

1. Flow Control: Needle valves are designed for fine control of flow rate, making them ideal for applications where precise adjustments are required.

2. Flow Restriction: They regulate fluid flow by adjusting the position of the needle relative to a seat, which helps in managing pressure and flow in the system.

Applications

1. Hydraulic Systems: Used to adjust the speed of hydraulic actuators or control fluid flow in hydraulic circuits.

2. Instrumentation: Commonly used in laboratory equipment and process control systems where precise flow measurement and adjustment are necessary.

3. Gas and Liquid Systems: Useful in both gas and liquid applications, including gas chromatography, fuel systems, and chemical processing.

4. Cooling Systems: Employed to regulate the flow of coolant in cooling systems, ensuring optimal temperature control.

5. Water Treatment: Used in water treatment facilities to control the flow rates of chemicals or water.

Design and Operation

1. Needle and Seat Mechanism: The core of a needle valve is the tapered needle, which moves into and out of a seat to regulate flow. By turning the valve stem, the needle's position changes, adjusting the flow rate.

2. Materials: Needle valves are made from materials like stainless steel, brass, and plastic, chosen based on the fluid being handled, temperature, and pressure requirements.

3. Types: There are various types of needle valves, including manual and automatic, as well as those with different connection types (e.g., threaded, flanged).

Installation and Maintenance

1. Installation: Install needle valves in the correct orientation as specified by the manufacturer. Ensure that the valve is compatible with the system's pressure and temperature conditions.

2. Operation: Use the valve handle or stem to make fine adjustments to the flow rate. Due to their precision, needle valves should be operated slowly to avoid damage.

3. Maintenance: Regularly inspect and maintain the valve to ensure it is functioning correctly. Look for signs of wear, leakage, or clogging, and clean or replace parts as needed.

4. Calibration: In systems where precise flow measurement is critical, periodic calibration of the needle valve might be necessary.

Advantages

1. Precision: Provides excellent control over flow rates, making it suitable for applications requiring fine adjustments.

2. Versatility: Can be used in various applications and with different types of fluids.

3. Compact Design: Typically has a compact size, which is advantageous in space-constrained environments.

Limitations

1. Flow Restriction: Needle valves can cause pressure drops due to their design, which may not be ideal in applications requiring minimal pressure loss.

2. Flow Capacity: They are generally not suited for applications requiring high flow rates, as the small orifice can create significant flow resistance.

3. Maintenance: The fine controls and small orifices can be susceptible to clogging, requiring regular maintenance and cleaning.