Hints on Installation of Valves
|
1 Valve Preparation and Positioning |
|
|
Ensure the valve and adjacent pipe work are clean and clear of packing material, etc. Place the valve between the pipe flanges using, if necessary, lifting gear attached to the body of the valve. Do not attach anything to the handwheel. When replacing, replace any information disks or plates which may have been secured beneath the handwheel nut. The attitude of the valve in the pipeline should, if possible, be such that the bonnent or cover can be removed for maintenance without having to remove the whole valve from the pipeline. In this way damage to expensive lagging (normally fitted up to the cover or bonnent joint) may be avoided. |
 |
|
2 Gasketed Valve Joints |
|
|
Preference should be given to purpose-made gaskets to suit the matching pipework flanges. If gaskets are to be used they should be carefully cut out to size. Do not cut the gasket by hammering the material over the edge of the flange as this will result in damage to the flange faces. Do not forget to cut out the centre of the gasket. |
 |
|
3 Pipe Flanges |
|
|
Pipe flanges should be checked to ensure that they are square with the associated pipeline. On no account should the difference between the face to face dimensions of the valve and that of the pipe flanges exceed 3 mm unless a definite “pull up cold” dimension is specified. |
 |
|
4 Making the Connections – Flanged Valves |
|
|
When the valve is in position, install bolts in all holes. Do up all nuts finger tight. Then tighten all nuts, one flange at a time, making sure that they are done up evenly. Check for even tightening from time to time by using a feeler gauge. When one joint has been made, repeat this procedure on the other joint.
Outside Screw Valves After installing valves having external operating threads operate them two or three times through the full limit of spindle travel and, at the same time, apply a suitable lubricant. This prepares the valve for future use and will also prevent corrosion of the spindle operating threads. The valve is now ready for a long period of satisfactory service. |
 |