Control valves
Control valves
What is a control valve?
Control valves accurately regulate and control water, chemicals and other fluids in a system. Either the valve controls the amount of fluid, or it distributes the flow to different branches of the system. The most common control valves are in poppet, diaphragm and butterfly valves.
Regulating your process
Lyma offers plug valves with equal percentage or linear characteristic. Equal percentage characteristic is used in flow, pressure and temperature control. Linear characteristic is commonly used in level control. The control valve works for both on/off and regulating applications, where an on-off valve simply refers to a valve that opens and closes. When selecting a control valve, it is important that you consider:
- how many cycles it should do
- the speed of opening and closing
- how tight the valve is expected to be when closed
Filter
Asahi ball control valve type 21a DN15-50
Richter lined control valve type RSS/F DN15-150
Richter lined ball valve for control type KNR/F DN15-200
Exner control valve type 640/650 DN15-100
How does the control valve work?
A control valve consists of three main components - a valve body, an electric or pneumatic actuator, and a positioner. The design also includes a seat and a spindle with a cone. A throttling action takes place between the seat and the spindle, with the spindle moving up and down with the help of the actuator. Its position is determined by the positioner (position).
The control valve must also be sized, which often means that the valve dimension differs from the pipe dimension.
What is depressurisation?
The purpose of the valve is to regulate a flow so that, for example, the desired pressure, temperature or flow is obtained. The regulation takes place by creating a pressure drop across the control valve, and it is the pressure drop that drives the flow - not the valve. The pressure drop can be described as the engine of the flow. The size of the flow is determined by the physical properties of the flow, the pressure drop across the valve and the flow characteristics of the valve.
The pressure drop across the control valve depends, among other things, on the Kv-value of the valve, the media, the pressure before the valve, the temperature and the flow through the valve. The Kv value of the valve is defined as the amount of water in m3/h that flows through a given valve at a pressure drop of 1 bar. In American literature Cv is used with the relation: Cv=1.17xKv.
In which versions are the control valves available?
Lyma offers, among other things, PTFE/PFA lined control valves. PTFE and PFA have the great advantage that they are resistant to virtually all types of chemicals. The valves are also manufactured in PVDF, PP or PVC, where the materials are resistant to most acids, alkalis, saline solutions and organic solutions miscible with water.
The valves can be connected via flange connection, weld connection or thread connection. The pressure classes, i.e. the maximum operating pressure for which the valve is designed, vary up to 25 bar depending on the model.
Are you looking for a control valve in the form of a control valve? The most common control valves are poppet valves, which are opened and closed by the actuator moving the valve shaft in and out.
At Lyma you will always find a wide range of control valves
Lyma is a safe choice when you are looking for valves for process industries. We are experts in abrasive and corrosive flow technology for the petrochemical industry, chemical industry, pharmaceutical industry and many others.
We help you choose the right control valve. Our range of control valves are ideal for harsh conditions such as high pressures, corrosive fluids, extreme temperatures and abrasive or toxic media. They can handle fluids such as
- iron chloride
- lye
- pickling bath
- hydrochloric acid
- lime slurry
- particle-laden liquids
Welcome to contact us if you have any questions!