Environmental Engineering Reference
In-Depth Information
hermometer
Capillary
tube
Scale
Union
fitting
Bulb
figure 4.44 Industrial thermometer.
Pointer
Scale
Bimetallic element
figure 4.45 Bimetallic gauge.
Body
Retainer tube
Spring
Ball
Seat
figure 4.46 Vacuum breaker components.
Air flows into the system to fill the vacuum. In water systems, when air
enters the line between a cross-connection and the source of the vac-
uum, then the vacuum will be broken and backsiphonage is prevented
(AWWA, 1996). The spring then returns the ball to its usual position,
which acts to seal the system again.
4.15.5 accumulators
As mentioned, in a plant compressed-air system, a means of storing
and delivering air as needed is usually provided. An air receiver normally
accomplishes this. In a hydraulic system, an accumulator provides the
