Pressure Seal Gate Valves -Style A-
Installation and Maintenance Instructions
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page 3
2.2 Installation Instructions
Gate valves are normally installed in horizontal pipe with vertical stem.
These valves can also be installed in vertical or horizontal pipe with stem other than vertical, but
this may require special construction depending on valve size, service condition, material and type
of operator.
For a correct operation, Sapag recommends that the valve shall be installed and oriented following
the indications of fig. 2.
This can help minimize any problem associated with solid particles present in the fluid that
otherwise could deposit in the lower part of the body and be obstacle to the wedge complete
closure.
Unless otherwise recommended by Sapag, the valve should be installed with the wedge in the
closed position, to ensure that the seat ring in the wedge is not damaged during installation.
Particular care should be taken with those valves equipped with ‘fail-open’ actuators.
For operating temperatures above 200°C (392°F) thermal insulation of the valve body is
recommended.
Handling and lifting of the valves during installation MUST be performed following the same criteria
and instructions described in previous points “1.2 Handling Requirements” and “1.3 Storage and
Preservation before Installation”.
Important
After the valves installation and before the line testing, it is recommended to perform an
accurate cleaning of the lines to eliminate dirt and any foreign objects that could seriously
jeopardize the tightness between seat/disc and the correct operation of the valve.
Buttweld Valves
Position the valve and check the alignment with the pipe, then proceed with welding, in
accordance with the applicable welding procedure.
Important
If piping system is pressurized with water for testing, and in case the piping system has been
shut down after testing for a long time, the following recommendations should be adopted.
a. Use corrosion inhibitor with water to pressurize the piping system
b. After testing, the piping system should be depressurized and the test water completely
drained.
2.3 Valve Verification before Start Up
1. Tighten the packing just enough to prevent stem leakage. Over-tightening will decrease packing
life and increase operating torque. The bolt torque figures for the packing bolts can be calculated
as indicated in Table I.
2. Check the operation of the valve by stroking it to “full open” and “full close”.
3. If the valve has been stored for a long time, check the bolt torque for bolting (pos. 31) in
accordance with table II.
2.4 Operations Instructions
1. Style A Series Gate Valves do not require special care to work properly.
The following instructions will help provide a satisfactory and long life service.
2. Make sure to perform periodic valve verification as described in paragraph 2.5.
3. In case of actuated valves always follow the specific instructions given by the actuator’s
manufacturer.
4. Never change the setting of torque and/or limit switches which have been carefully set during
the final test at Sapag workshop.
Figure no. 2
Installation positions
recommended
90°
max.
