What is a normally opened valve? Why is it called normally open? Please refer to the article below by valve sales engineers
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1. What is normally open valve
Normally open valve is a valve that can close, open or regulate flow. However, in normal state, the valve is always open. The normally open characteristic of the valve also means that at the installation location the valve rarely needs to block or regulate flow.
Valves can be conventional types of valves but always in an open state, such as: ball valves, butterfly valves, gate valves,… or solenoid valves.
2. NO valve symbol meaning
NO stands for Normally Opened, so NO valve is a normally open valve. Normal open Valves are denoted on design drawings by a non-bold valve symbol
3. When to use NO valve
Normally open valve is used at locations on the pipeline with characteristics
- The valve installation location rarely requires blocking or regulating the flow with reduced flow
- In cases where blocking or regulating the flow is required, it is rarely used
4. Normally open valve type
Although NO valve can be many different types of valves. However, experts often say that it is a normally open solenoid valve to distinguish it from a normally closed valve. Because, solenoid valve is a valve with a high frequency of opening and closing.
5. Normally open valve voltage
Normally Open Solenoid Valve is referred to as having a variety of voltage like solenoid valves in general. Below are the types of power sources that valves commonly use
- 220VAC
- 24VDC
- 12VDC
6. What is the difference between NC and NO valves
Normally closed and normally open solenoid valves of the same size may look identical, but the valve mounting location and internal construction are different.
- A normally closed (NC) valve remains closed, blocking flow, until energized to open.
- A normally open (NO) valve remains open, allowing flow, until energized to close.
7. Normally open valve application
The application of valves is something that only users, sales engineers or valve experts understand. Valves are used in a number of situations
- Close the valve when a fluid change is required
- Close the valve for mixing
- Close the valve to allow the system to perform another task for a short time