Angle seat valves (piston valves)
Pneumatically operated angle seat valves for steam, hot water and frequently cycled lines; normally closed, normally open and double acting.
Steam, superheated water and lines that cycle hundreds of times a day quickly wear out the seal of an ordinary valve; the angle seat piston valve is built for this duty. On process lines we select the valve for the fluid temperature and the number of cycles, and install it together with the pilot valve and air preparation its control requires. We ship angle seat valves from stock across Türkiye and abroad, and also sell them through hidroticaret.com, our online store (Turkish).
Types
Normally closed (NC)
The spring holds the valve closed and pilot air opens it; the valve closes when air fails.
Normally open (NO)
The spring holds the valve open and pilot air closes it.
Stainless steel angle seat valves
For food, pharmaceutical and chemical processes; body resistant to corrosion and washdown.
Double acting
Opening and closing are both done by pilot air; provides positive shut-off on high pressure lines.
Product images: hidroticaret.com and manufacturers.
How to select
In an angle seat valve the flow path is inclined and the seal sits squarely on the seat; the fluid passes almost straight through, so flow is high and pressure drop is low. Because the piston is operated by air, the hot fluid does not reach an electric coil; on steam it lasts much longer than a solenoid valve.
Temperature drives the selection. On a steam line the fluid temperature rises with pressure; the table below gives the temperature of saturated steam by pressure. The temperature limit of the valve and its seal is selected above this value.
Flow direction matters: some valves take the flow under the seat and others over it, and a valve installed the wrong way round causes water hammer or does not close fully. The arrow on the body shows the flow direction. As with actuators, the pilot air must be filtered and regulated.
Saturated steam temperature by pressure
| Steam pressure (gauge) | Temperature |
|---|---|
| 1 bar | 120 °C |
| 2 bar | 134 °C |
| 3 bar | 144 °C |
| 4 bar | 152 °C |
| 5 bar | 159 °C |
| 6 bar | 165 °C |
| 8 bar | 175 °C |
| 10 bar | 184 °C |
Values are rounded from steam tables, based on atmospheric pressure at sea level. Superheated steam is above these temperatures.
Frequently asked questions
Why are angle seat valves preferred for steam?
They are operated by air, so the hot fluid does not reach an electric coil. The seal and body are made for high temperature and frequent cycling.
What is needed to operate an angle seat valve?
Compressed air and a solenoid valve that supplies pilot air to the valve. A filter regulator should be installed on the air line.
Does flow direction matter on an angle seat valve?
Yes. The arrow on the body shows the flow direction; a valve installed in reverse may cause water hammer or may not close fully.
Should I choose NC or NO?
NC if the line must close when air fails; NO if it must stay open.
What information do I need to provide?
Fluid, temperature, pressure, connection size and control type (NC, NO or double acting).
Stock, sizes and part numbers
We select and supply the products in this group according to the application. Send us your requirement, the size and the operating conditions on WhatsApp and we will recommend the right product.