Hydrophore unit
To supply water by pressure for shipboard consumers utilizes hydrophore unit with the pressure of the compressed air in the tank.
In large and medium-sized ships, there should be at least two kinds of pressure tank: one is sea-water pressure tank for sanitary water, the other is fresh-water pressure tank for drinking and washing.
To the main particulars of hydrophore unit commonly belongs: capacity (m3 or L), working pressure (MPa), design pressure (MPa), hydrostatic test pressure (MPa), dimensions (l×b×h mm).
Hydrophore unit general view is depicted in figure below.
Hydrophore unit general view
I – pump inlet, II – FW outlet, III – drain outlet, IV – air inlet, 1 – centrifugal pump, 2 – safety valve, 3 – pressure tank, 4 – control box, 5 – air charging valve, 6 – name plate, 7 – pressure gauge, 8 – pressure switch, 9 – seat, 10 – valve, 11 – glass level gauge, 12 – manhole cover, 13 – drain valve, 14 – base plate
Safety valve 2, air charging valve 3, drain valve 13, pressure gauge 7, glass level gauge 11 and inlet and outlet flanges are installed on the pressure tank 3. When the pressure in the tank 3 is over the limited pressure, safety valve 2 opens automatically for the sake of safety. Air charging valve 3 uses to control open and close of compressed air pipelines. Pressure gauge 7 shows air pressure inside the tank. Glass level gauge 11 shows the liquid level in the tank directly. Routs will be closed automatically to avoid liquid loss for safety when a fire or broken of glass pipes occurred. Centrifugal pump 1 install in the left side of the pressure tank 3.
The working principle of the hydrophore unit is showed in figure below.
Working principle of hydrophore unit
Because the pressure tank is airproof, when we fill water in tank 2 through pump 1, with the elevation of water level, the air inside the upper part of the tank is compressed and generates pressure. When the water reaches the required level, pump 1 is stopped and cease to supply water. With the pressure of the air in the upper part of tank 2, water can be pumped through pipeline, valve to consumers. In order to make sure the tank perform regularly, there are pressure gauge 9 and safety valve 8 and pressure switch 7 are set up to control pump 1. When the pressure in the tank is lower than the minimum working pressure, the pressure switch 7 will automatically activate pump 1. When the pressure in the tank reaches the set maximum working pressure, the pressure switch 7 will also automatically stop the water pump 1. To reduce the size of the tank and supplement the air, usually an air inject tube is set on top of the pressure tank.