Section 2
2.1 LIMIT SWITCH
The limit switch assembly of an actuator fitted direct onto a valve is set forthe correct number
of turns before despatch and should not be disturbed.
Pedestal type actuators and actuators for fitting direct on to valves at site are despatched with
each switch bank set at 50. 0 turns so that any mal- operation of the handwheel before the
actuator is coupled or fitted to the valve should not disturb the correct relationship of cams to
rollers. After coupling or fitting the actuator to the valve remove the limit switch cover. Hand
operate the valve to the full shut position, and observe that the limit switch cams are in the
correct re- set position. Maximum cam throw to operate switches 72° clockwise for open or
intermediate, anti-clockwise for close. f for any reason the cam is in any other position, the
correct position is easily attained by separating the spur wheel and the hunting tooth wheel
which registers multiples of 10. Turn the hunting tooth wheel in a clockwise or anti-clockwise
direction until the correct cam position is obtained and re-engage with spurwheel. This should
be carried out without disturbing the remaining digits. After noting the actual number of turns
indicated on the 'close' bank hand operate the valve in the open direction 0.3 turns of the limit
switch counter mechanism to the nearest 0.1 turn which will give a complete number in a
straight line, in line with the pinion and hunting tooth spindles. Reset the 'close' bank to 000
turns (in line) and re-engage each spur wheel and hunting tooth gear. Now set the
'intermediate' and 'open' banks to the correct number of actuator output shaft turns from zero
at which these switches are required to trip.
2.2 COMMISSIONING PEDESTAL UNITS
First ascertain that the valve is in the full shut position i. e. the stop is resting on the lower
shoulder of the valve pillars. Connect the valve and unit mechanically by the extension spindle
supplied taking care not to move the valve from the full shut position and also ensure that the
universal forks on the intermediate shaft are in line and not at 90° to each other.
2.3 COMMISSIONING DI ECT MOUNTED ACTUATO S
Valves which are to be fitted with direct mounted actuators at site are fitted with a circular
adaptor plate secured to the valve by the pillar nuts.
f a standard hand operated valve is to be motorised by means of a direct mounted actuator,
remove the existing handwheel, gearing (when fitted) sleeve and bridge, leaving the valve
pillars and spindle only for application of the actuator. Remove the circular adaptor plate from
the base of the actuator and fit this item on the valve pillar ends and secure by means of the
existing pillar nuts. Do not remove any covers at this stage but engage manual operation in
preparation for fitting to the valve.
Sling the actuator by means of overhead tackle and carefully lining up the actuator with the
valve spindle axially and radially, lower the actuator on to the valve until the output shaft begins
to engage the valve spindle. Rotate the handwheelin the opening direction, and, at the same
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