Bourdon tube pressure gauges are used for a number of applications, including oil drilling, ocean liner operations and manufacturing plants. These gauges inform the operator concerning the amount of pressure in tanks or running through pipework. This pressure can involve air, steam, water, oil or other materials. The machinery operator should calibrate the pressure gauge to ensure the readings are accurate.
Things You'll Need
Remove the screws for the pressure gauge's threaded casing. Place the pliers on the edge to pry off the casing, ring and gauge window. Also remove the screws from the rear casing if the pressure gauge has a solid front case.
Pressurize the system once so the the gauge pointer shifts from zero to the highest pressure measurement, then back to zero. Place the tip of the pliers against the pointer and set it to the position of zero if it is not at that position.
Put the system through full pressure again. Visually inspect the reading to see how far off the pointer is from a full pressure reading. Replace the pressure gauge if the reading is more than 10 percent off, since this indicates the bourdon tube has corrosion.
Loosen the link screw to adjust the link if the pressure gauge reading is off by .25 percent or more, yet not over 10 percent. Move the link screw closer to the rotary movement to increase the pressure reading span. Move the link screw farther away from the rotary movement to decrease the pressure reading span.
Calibrate midscale pressure indication by applying system pressure only to the halfway point. Adjust the link by closing the pliers on the left and right side to gently squeeze the link. This increases the pressure pointer indicator. Close the pliers on the top and bottom of the link to decrease the pressure pointer indicator.