Product Description
Page 32 of 92
User Manual QT250 and QT800 gen 2.5, ID 2021 2.3 20. April 2021
The actuators provide fastening holes of different dimension to facilitate
mounting on different types of valves, see details in
on page 36 and
on page 37.
When the actuator and the valve do not have a natural match, it is necessary to
use an adaptor. There are various adaptors available, but the two most common
ones are the square reducer and the stem adapter. When buying
actuator and valves together from Eltorque, this is handled by our project
personnel. If you order just the actuator take care to verify the critical
dimensions and whether the valve has parallel or standard configuration. Square
reducers might be necessary. Always use two pieces with QT250. The QT800
only has room for one. The type of reducer to be used depends on the valve type,
please contact your Eltorque representative or Eltorque support for further
details.
Figure 19: QT250 and QT800 Settings for closed position.
The setting for closed position can be changed by using E3C, see
Eltorque E3C
Manual
.
The actuator must have enough torque to operate the valve in all situations with
an acceptable safety margin. Valve type, temperature, operating pressure,
medium density and viscosity and the medium’s effect on the valve friction are
among the variables that need to be evaluated. A change in any of these
variables may change the required operating torque. Preferable a torque table
with all parameters should be used, but for an electrical actuator, the output
torque is constant, reducing the considerations to be made. Using the break to
open (BTO) value usually gives a correctly sized actuator. The break to open
torque is defined as the torque required to move the valve out of the seat.
Be aware that the MAST of the valve needs to be verified to prevent damage to
the stem. Eltorque can assist with the necessary experience in selecting the
correct actuator size for the valve.
For the QT250 and QT800, the closing time is configurable within a predesigned
interval. The opening and closing profiles are shown in
performance parameters for QT250 and QT800 actuators
on page 19.
Summary of Contents for QT250
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