Презентация на тему Water services

of air under pressure is maintained in the top

of a pressure vessel
When a tap is opened the air is able to expand by forcing the water out of the cylinder and through the pipe work
This process can continue until the water level drops to a predetermined point, when the pumps will be switched on to raise the level again
Drinking water is drawn off from the pressure vessel, although the drinking water can be supplied direct to lower floors where the mains pressure is sufficient

high rise buildings there is often insufficient mains pressure

to supply water directly to the upper floor
Boosting by pumps from a break tank is therefore usually necessary and several more of these tanks may be required as the building rises-depending on the pump capacity
A break pressure cistern is also required on the down services to limit the head or pressure on the lower fitting to max of 30m (approx. 30kPa)
Drink water header pipe or storage vessel supplies drinking water to the upper floors
As this empties and the water reaches a predetermined low level, the pipe line switch engages the duty pump
A float switch in the break tank protects the pump

to the drinking water header pipe. An auto-pneumatic cylinder

may be used
Compressed air in the cylinder forces water up to the float valves and drinking water outlets on the upper floor
As the cylinder empties a low pressure switch engage the duty pump
When the pump has replenished the cylinder, a high pressure switch disengages the pump
In the time some air is absorbed by the water
As this occurs, a float switch detects the high water level in the cylinder and activities on air compressor to regulate the correct number of air
Break pressure cisterns may be supplied either from the storage cistern at roof level or from the rising main

supplies must be protected against pollution by back siphonage
Protection

is effected by leaving sufficient space or air gap between the lowest point of the control device
There must be an air gap between tap discharge and the appliance spill over level

used to regulate cistern water supply from an auto-pneumatic

cylinder and pump activity will be frequent and uneconomic
Therefore, to regulate activity and deliveries to the cistern, a delayed action float valve mechanism is fitted to the storage cistern

SHOWER PUMP