Global Water Pressure Tanks

Pressure vessels are important components in automatic booster systems, the vessels cushioning pressure surges as the pump starts and stops and also provide drainage supply in to the system to reduce pump cycle frequency.

DAYLIFF Global Max pressure tanks are high specification units that are suitable for high pressure applications and include the following features:

  • Super thick steel construction with polyurethane and epoxy painted paint finish for corrosion protection
  • Polypropylene liner so tanks can be used for corrosive and hard waters
  • Special diaphragm and air valve design that eliminates air leaks and the need for maintenance.

DAYLIFF Global Max pressure tanks are comprehensively tested and quality approved by a number of international standards organisations and are also FDA food grade approved pressure tanks. They are the ideal solution for all high specification water booster applications and will provide many years of maintenance free operations.

Correct tank sizing is important and is determined by the system flow rate and pump start and stop pressure settings. Sizing must be based upon the system flow at which the maximum cycle frequency occurs. As a rule of thumb this can be taken as average flow between the cut-in and cut-out flow rates.

Required drain volume is then the maximum cycle frequency flow divided by twice the specified maximum number of cycles per hour. Generally 60 cycles per hour is considered acceptable. Tank size selected is then that nearest to the volume required. Some selected examples are as follows;

Pump Start Pressure (bar) 2.5 3 3 4 5 6 10
Pump Stop Pressure (bar) 4 5 6 8 10 12 15
Drainage % 28 31 41 43 43 45 29
Tank Model Drainage Volume (Litres)
GWS 24Litres 7 8 10 11 11 12 7
GWS 60Litres 17 18 24 26 26 27 17
GWS 100Litres 28 31 41 43 43 45 29
GWS 300Litres 84 93 123 129 179 135 87

Correct tank precharge is critical and must be 0.2 Bar below the pump start pressure for pressure switch systems or 65% of the pump stop pressure for variable speed systems. Efficiency is greatly reduced if precharge is either too high or too low.
Ensure that the difference between start and stop pressure is as high as possible as the larger the differential the greater the tank drainage capacity.
Ensure the pump start pressure is higher than the system static pressure or else the pump will not start.
Adjust pump stop pressure to be about 90% of the pumps closed head pressure.

NOTE: Oversizing tank size has many advantages including reduced energy consumption, reduced cycling, extended pump life due to reduced wear and reduced noise. As a rule doubling the calculated size will bring substantial benefits.

System Parameters
Pump Start Pressure: 5 Bar
Pump Stop Pressure: 10 Bar
Maximum Working Temperature:90°C
Stop Flow: 5m³/hr
Start Flow: 10m³/hr

Required Drainage Volume: = Average Flow Rate / (start per hour x 2) e.g. 7500ltr/hr / (60 starts/hr x 2) = 63litres
Drainage % based on start/stop pressure as per table: 43%

Required Tank Volume = Required Drainage Volume / Drainage % e.g. 63 / 0.43 = 146litres
Tank Specification: Use 2x100litres or 3x60litres

Tank Data

Model Max. Pressure (bar) Type Dimensions Weight (kg)
GWS24 10 Diaphragm 447 293 - 9
GWS60 16 Diaphragm 620 390 127 15
GWS100 16 Diaphragm 804 431 129 22
GWS300 10 Bladder 1511 534 130 79
GWS300 16 Diaphragm 1230 640 130 79