Introduction to Flow Control Valves

Flow control valves are used to regulate the material withdrawal from silos, bins etc. when mounted along with PneuSlide (Pneumatic Air Activated Gravity Conveyor). These valves are designed to manage the flow of materials, ensuring optimal performance and efficiency. In this article, we will explore the various types of flow control valves, their functions, and the benefits they offer in different industries.

Understanding Flow Control Valves

What are Flow Control Valves?

Flow Control Valves

For the regulated discharge of pulverized bulk commodities like cement, lime, gypsum, and fly ash, flow control valves are used to close off the discharge spouts of silos. An unhindered flowthrough is guaranteed by flow control valves. The picture above shows the flow control valve.

How do Flow Control Valves Work?

Flow Control Valve

The flow control valve is an element to be placed between fluid slides. It consists of an upper box (A) which forms the conveying chamber and a lower box (B) which is supplied with compressed air. Upper and lower box are separated from each other by a fabric permeable to air.

When the roller rotates into one direction, the silo discharge opening is closed, when the roller rotates into the other direction, the adjustable aperture is opened, so that the fluidized bulk good can flow through.

Flow Control Valve

How Roller type affects flow in Flow Control Valves

Flow Control Valve

Types of Flow Control Valves

There are several types of flow control valves available, each with its unique characteristics and applications. Let’s explore some of the commonly used types:

Manual actuated Flow Control valves

Flow Control Valve

In general, manual flow control valves equipped with coupling and lever are used for power actuated valves. This allows to add a gear motor or pneumatic piston later on if required. All types of flow control gates are equipped with a switch box containing three limit switches for the positions ‘open’, ‘intermediate’ and closed’. Furthermore, there is a potentiometer for remote control indication.

Pneumatic controlled Flow control Valve

Flow Control Valve

Pneumatic piston controlled flow control valves are equipped with a double acting pneumatic piston controlled by a special 5/3 way valve which makes it possible to stop the gate in any position required.

In case of power failure the flow control valve will automatically move into the ‘closed’ position.

Motor controlled Flow control Valve

Flow Control Valve

Motor actuated flow control valves are equipped with a gear motor or with a torque motor. Gear motors can be positioned in four different ways, i.e. ‘top right’, ‘top left’, ‘bottom right’ and ‘bottom left’. The standard type is top right. The actuating velocities for a full way of 90 degrees are 8, 25, 45 or 60 sec. depending on the requirements.

Factors to consider before choosing the right Flow Control Valve

Actuation

You need to ascertain whether the valve is manually turned on and off by hand or whether an actuator is needed to do so. If you select on the latter, you have chosen the device that will be utilized if a hydraulic or pneumatic actuator is needed.

Material

Considering the material properties and environmental conditions, selecting the right valve is essential for longevity and performance. Factors such as compatibility, corrosion resistance, and temperature range should be taken into account.

Flow Rate Requirements

Understanding the required flow rate is essential in choosing the right flow control valve. Different valves have varying capacities, and selecting the appropriate valve size ensures optimal performance and avoids flow restrictions or inefficiencies.

Maintenance Requirements

Regular maintenance is necessary to prevent clogs in the gate valve, which must be maintained. As a result, this is the most straightforward approach of giving you gate valves that will last a long time. The gate valves are created in a way that makes cleaning them simple without requiring disassembly.

Use Case: Cement Industries

Flow Control Valve

The movement of raw material between the pre-bin and the weighing apparatus is regulated by flow control valves. For this kind of application, electro-pneumatic control devices are employed with pneumatically controlled flow control valves. With the help of a signal exchange with the flowmeter, the material flow is managed.

Without using lever arms, toothed racks, or gears, the pneumatic actuators work on the rotating paddle pneumatics principle. Because there are no intervening side forces on the square drive, the pure torque may be delivered. The actuators, which stand out for their lightweight and compact form, require little to no maintenance.

The actuator mechanism has ventilation choices as well, allowing for manual movement (hand lever). The stand-by equipment’s flow control gates can be precisely adjusted through remote control to match the main line’s present operating position. The configuration of a weighing station with flow metering equipment is shown in the above figure.

Conclusion

Flow control valves are essential parts in many sectors because they allow for precise control of fluid flow rates and increase system effectiveness. Industries may streamline their procedures and enhance overall performance by having a thorough awareness of the various flow control valve types, their applications, and the variables to take into account when choosing and maintaining them.