_____________________________________________________________________________________
STI S.r.l.
– Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5400, rev. 05 02/2018
– RTQHS
13
6
OPERATION AND USE
6.1
Operation description
The RTQHS is a hydraulic actuator designed for on-off and control service and is applicable over a wide
range of pressure, temperatures and environments.
The scotch yoke mechanism converts the linear motion of hydraulic piston or spring into valve rotation by
the actuator shaft. The symmetric scotch yoke mechanism generates high torque at start (0° degree) and
the end (90° degree) of the valve stroke, typically valve torque figure of ball valve. The canted scotch yoke
mechanism generates very high torque when valve is closed, typically valve torque figure of butterfly valve.
For Single acting actuator RTQHS the spring cartridge is located on the other side of actuator housing. The
spring provides the required safety function, the valve either opens or closes if the hydraulic supply is
interrupted Safe spring design ensures proper functionality and safe maintenance, preventing any
accidental hazards due corrosion of bolting.
6.2
Intended use
The machinery covered in this Instruction Manual is single acting hydraulic RTQHS actuator series
designed to operate a quarter turn industrial valve (ball valves, butterfly valves, plug valves,
dampers,...) for ON-OFF or modulating heavy duty service.
This RTQHS actuator is produced by
STI srl
[Manufacturer] and identified by a label with a product
designation code.
STI srl
will not be liable for any possible damage or physical injury resulting from use in
other than the designated applications or by lack of care during installation, operation, adjustment and
maintenance of the machine. Such risks lie entirely with the user. Depending on the specific working
conditions, additional precautions may be requested. Considering that
STI srl
has no direct control over
particular applications, operation
or maintenance conditions, it is the operator’s responsibility to comply with
all applicable safety rules. Please inform
STI srl
urgently if you face unsafe situations not described in this
Instruction Manual. It is the sole responsibility of the operator to ensure that the local health and safety
regulations are adhered to.
RTQHS actuator is designed in accordance with the applicable International Rules and Specifications, but
the following Regulations must be observed in any case:
-
the general and safety regulations
-
the plant specific regulations and requirements
-
the proper use of personal and protective devices (glasses, clothing, gloves, etc)
-
the proper use of tools, lifting and transport equipment.
Warning
It is severely forbidden to use the RTQHS actuators series for purpose or
application other than those for which it was designed and here above specified
6.3
Reasonably foreseeable misuse
A short list of reasonably foreseeable misuse :
-
Installation in ambient with not planned conditions: i.e. climatic conditions different from the specified
conditions;
