Ball valve VL851 with double-acting drive - DN20
Code: VL851-020DA
Product detailed description
Ball valve VL851-020DA
- vL851F flanged ball valve system and OMAL type DA pneumatic actuator
- PTFE seal for temperatures up to 190°C
- actuator operating pressure of at least 5.5 bar
- for sealing aggressive media pipelines in the chemical and food industry
Additional parameters
| Category: | Ball valves VL851F with pneumatic actuator |
|---|---|
| Pressure: | 16 bar |
| Connecting: | Flange |
| Material: | Stainless steel |
| Medium: | Air, Water, Aggressive media |
| Standard: | DIN 3202-F4, EN 1092-1, EN 558-1, ISO 5211 |
| Brightness DN: | 20 |
| Seals: | PTFE |
| Drive type: | Double acting pneumatic drive |
| Controls: | Pneumatic drive |
| Design of fittings: | Automated, Intermediate flanges, Two-piece |
Product rating
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OMAL is an Italian company from Rodengo Saiano near Brescia, founded in 1981 by a family specialised in making ball valves. Today it designs and manufactures valves and actuators for controlling the flow of media, ISO 9001 certified since 1992.
We offer ball valves with OMAL pneumatic actuators — two-way and three-way, threaded and flanged, in brass, cast iron, steel and stainless steel — as well as separate DA and SR pneumatic actuators with ISO 5211 mounting for fitting to your own valve.
Italian brandOMAL actuated valves and actuators
02TTT with actuator — cast iron
Flanged valve for non-aggressive media. Pekos 02TTT cast iron valve with an OMAL DA or SR pneumatic actuator.
- DN15 to DN200
- PTFE seal up to +200 °C
- actuator control pressure min. 5.5 bar
VL851 and VL140F with actuator
Stainless flanged valves for aggressive media. Flanged or wafer valves with a DA or SR actuator.
- DN15 to DN100
- PTFE seal up to +190 °C (VL851)
- chemical and food industry
VL521 and V101 with actuator
Threaded valves with an actuator. Three-piece stainless VL521 for aggressive media, brass V101 for water and air.
- thread 1/4″ to 4″, VL521B with weld ends
- DA or SR actuator
- temperature up to +120 °C
K806 and K809 — high pressure
For high pressure and temperatures up to +250 °C. Stainless K806 or steel K809 with PTFE+CG seals and a DA or SR actuator.
- female thread or weld ends
- EN 10204-3.1 certificate
- actuator control pressure min. 5.5 bar
86TTT and 84TTT — three-way
Flanged three-way valves with an actuator. Stainless 86TTT or steel 84TTT with an L or T port ball and a single-acting SR actuator.
- DN25 to DN200
- PTFE seal up to +180 °C
- 40 bar up to DN80, 16 bar from DN100
VL321 and V153 — three-way threaded
Threaded three-way valves with an actuator. Stainless VL321 with an L or T port ball for aggressive media, brass V153 with an L port for water and air.
- female thread 1/4″ to 2″
- stainless up to 63 bar, brass up to 16 bar
- DA or SR actuator, up to +120 °C
DAN actuators — double acting
Air opens and closes. Separate pneumatic actuators in anodised aluminium with NBR seals.
- DA008 to DAN1920, 8–1,920 Nm
- ISO 5211 flanges F03 to F14
- NAMUR, VDI/VDE 3845 interface
SRN actuators — spring return
A spring turns them back. If the air supply fails, the spring returns the valve to its default position.
- SRN15 to SRN960
- ISO 5211 flanges F03 to F14
- anodised aluminium, NBR seals
Need a valve without an actuator, for example for later automation, or a position sensor? All ball valves and fittings are in one category.
Valves and fittingsDA and SR actuators side by side
| Actuator type, operation, air failure, sizes and mounting | ||||
|---|---|---|---|---|
| Actuator | How it works | If the air fails | Sizes | Mounting |
| DAN — double acting | air turns the valve both ways | the valve stays in its last position | DA008 to DAN1920, 8–1,920 Nm | ISO 5211 F03–F14, NAMUR |
| SRN — spring return | air turns one way, a spring turns it back | the spring returns the valve to its default position | SRN15 to SRN960 | ISO 5211 F03–F14, NAMUR |
The actuator size for each valve size is listed in the table of the relevant actuated valve category.
How to choose an actuator for a valve
1. Double acting or spring return
A DA actuator opens and closes with air. An SR actuator turns the valve back with a spring, so it returns to its default position if the air fails.
2. Actuator size
The actuator must deliver more torque than the valve needs to turn. For ready-made assemblies, the actuator for each valve size is listed in the category table.
3. Mounting
The actuator and valve are joined via an ISO 5211 flange and a square drive. The flange size, such as F05 or F07, and the square must match.
4. Air and control
A pneumatic actuator needs a control pressure of at least 5.5 bar and a valve that switches the air to the actuator. A limit switch box reports the valve position remotely.
Frequently asked questions
- What is the difference between DA and SR actuators?
- A DA (double-acting) actuator turns the valve with air in both directions. An SR (spring-return) actuator turns it one way with air, and a spring turns it back, even if the air fails.
- Can an OMAL actuator be fitted to another valve?
- Yes, if the valve has an ISO 5211 flange with the same flange and square size. Valves prepared for automation include V101, V153 and VL521B.
- Which valve material should I choose?
- For water, air and other non-aggressive media, brass V101 and V153 valves or the cast iron 02TTT are enough. For aggressive media in the chemical and food industry choose stainless steel, such as VL521, VL321, VL851 or 86TTT. For high pressure and temperatures up to +250 °C there are K806 and K809.
- How can I tell which position the valve is in?
- Pneumatic actuators have a position indicator on top. For remote monitoring add an electric limit switch box, and for positioning in between use the VT1000ER positioner.
- What air pressure does a pneumatic actuator need?
- For ready-made valve and actuator assemblies the control pressure is at least 5.5 bar. To make the actuator last, supply it with clean, treated air.
- Where does OMAL come from?
- OMAL was founded in 1981 by a family of ball valve makers in Polaveno in Val Trompia near Brescia. In 1987 it moved to Villa Carcina, in 2008 it opened a plant in Rodengo Saiano, its headquarters today, and since 2016 it has manufactured in Passirano.
OMAL is a brand of the Italian company OMAL S.p.A. from Rodengo Saiano. Dimensions, torques and mounting details are in the category tables and on the product pages.