Rif. UMA800081C - 06/22
IT
EN
EN -
3
OMAL S.p.A.
Headquarters
: Via Ponte Nuovo, 11 - 25050 Rodengo Saiano (BS) Italy •
Production Site:
Via Brognolo, 12 - 25050 Passirano (BS) Italy
Ph.
+39 030 8900145 •
Fax
+39 030 8900423 • [email protected] •
www.omal.com
INSTRUCTION MANUAL
AGO: SCOTCH–YOKE PART TURN PNEUMATIC ACTUATOR
DA2880 - DA8000 - SR1440 - SR4000
1) GENERAL FEATURES
OMAL S.p.A. produces a wide range of pneumatic actuators, with “Scotch yoke” mechanism, for valve drive and remote control. Such
actuators are available both in the double acting “DA” version and in the Spring Return “SR” version.
The use of an actuator is based on the principle of opening and closing the valve connected to it, without manual operations by means
of levers or hand-wheels, but through an electro-pneumatic remote command.
The “Scotch yoke” mechanism is a mechanical system designed to transform the linear force into a torsion-type force.
OMAL S.p.A. uses this system, when producing its actuators, to transfer the linear force of the pistons to the movement of the valve
shaft.
This system provides a long life for the actuator and the best performance, with the least energy consumption.
The OMAL S.p.A. Scotch yoke system has a torque curve that makes the maximum torque available right at the breakaway of the
valve, the initial opening moment.
2) OPERATION CONDITIONS
a. Structure.
The OMAL S.p.A. actuators can be used both for indoor and outdoor installations. The technical characteristics such as: the type,
the size, the maximum operating pressure, the torque supplied, the maximum operating temperature, the flange type, the serial and
production number, are laser engraved on the actuator body (see drawing on page 6).
b. Supply fluid
The operating media should be dry and filtered compressed air not necessarily lubricated or inert gases compatible with internal ac-
tuator parts and lubricants.
The operating medium shall have a dew point equal to – 20 °C or, to be at least, 10 °C below the ambient temperature (ISO 8573-1,
Class 3). The maximum particle size shall not exceed 40 μm (ISO 8573-1, Class 5).
c. Operation pressure.
The maximum operating pressure is 8,4 bar (120 psi), 7 bar (100 psi) for the DA8000.
The nominal operating pressure is that which can be found on the plate or on the actuator directly.
d. Operating temperature.
The operating temperature can be found on the plate and can vary according to the types of seals that are being used. The OMAL
S.p.A. actuators work within a temperature range that goes from –20°C (-4°F) to 80°C (176°F); there are also versions that can be
used with low or high temperature (paragraph 8).
e. Stroke of the actuators.
The OMAL S.p.A. actuators are produced for a standard stroke of a 91° rotation; an adjustment that reduces the stroke by 10° (in the
closed valve position) is available upon request.
f. Opening and closing rates.
The cycle rate depends on different factors such as the supply pressure, the capacity, the connection sizes, the characteristics of the
solenoid valves, the room temperature, the valve torque and its characteristics. The rates in the following charts relate to the actuator
only and have been recorded with the help of the limit switches located on the actuator shaft. The rates are therefore exactly what is
required by the actuator for a 90° rotation, counting from the instant that the movement begins until the end of the stroke.
Below you will find the safety instructions, the minimum information for storage / warehousing, the installation, the commissioning, the
maintenance and the instructions for disposal of products at the end of their life cycle for the following pneumatic actuators:
A) DOUBLE ACTING PNEUMATIC ACTUATORE SERIES DA2880-DA3840-DA5760-DA8000
B) SPRING RETURN PNEUMATIC ACTUATORE SERIES SR1440-SR1920-SR2880-SR4000
Where provided, the actuators are marked in accordance with the applicable EX regulations.
OMAL S.p.A. disclaims any liability for damage caused by improper use, even if partial, respect to the information contained in this
manual.
