To make the best choice, you should always ask yourself the first question when selecting a valve: What tasks should the valve perform? Most valves perform one of five basic functions - open/close, flow control, control of flow direction, overpressure protection and flow limitation. Matching the valve type to the function is the first and most important step in valve selection. It is not uncommon to find misapplied valves in applications, such as a ball valve that was used to restrict flow. In some cases, the wrong choice can have catastrophic consequences, for example, if a ball valve were used in a high-pressure oxygen system.

Open / close: the most basic valve function

The open/close control is the most basic valve function. Valves in this category stop the flow of fluid and start it again. Ball valves, shut-off valves, diaphragm and bellows valves are the primary on/off valves.

Ball valves, probably the most common type of valve, are designed for open/close control. Flow is started or stopped with a 90 ° actuation by placing a metal ball in the straight flow path. A large hole runs through the centre of the ball. When the bore is aligned with the flow path, flow is enabled. If the ball is rotated 90 degrees away from the flow path, the flow will stop. The position of the handle shows quickly whether the tap is open or closed. In addition, ball valves can be easily blocked and marked for safety purposes. They are the most practical and economical in sizes between 6- and 50-mm. stainless steel shaft manufacturers in india manufactures the best valve.

Control the flow with control valves

Control valves allow the operator to increase or decrease flow by turning the handle. He can set the valve to the desired flow rate, and the valve reliably maintains that flow rate. The most common flow control valves are needle valves, fine metering valves, quarter-turn stopcocks, and straight-through regulating valves.

Swagelok needle valve Needle valve

Needle valves offer very good flow control and - depending on the design - a leak-tight shut-off. They consist of a long spindle with a technically mature geometry of the spindle tip, for example, V or needle shape, which fits exactly into a seat above the entrance. The spindle has a fine thread that allows precise flow control. The spindle packing provides the seal to the atmosphere. Some versions have an all-metal seat seal. Needle valves are therefore a good option for high-temperature applications and a good choice for lighter, less viscous fluids.

To get the most precise flow control, fine metering valves, which are typically found in laboratories, should be used. Fine metering valves are a type of needle valve with a long, fine spindle that descends through a long, narrow channel. This construction is a model with a pronounced deflected flow path, with which one can ideally achieve fine gradations of the flow. Some of the fine metering valves are not intended to be shut off. stainless steel hex bar suppliers will provide you with the best valve in India.