HFm devices
Introduction
There are lots of problems associated with the adjustment of production to consumption in drinking and technical water supply systems. When pump stations are used for water supply the production depends on pumps working properties that have limited justifiability whereas the actual consumption can be realized without fixed limitations. Unrestricted switching on and off of the pumps in order to meet consumption need is not allowed. This is done at specific intervals only which, in bigger pumps, may range between 8 to 12 (15) cycles per hour.
Similar problems are encountered with the supply systems where pressure depends on consumption and can drop very low in maximal consumption. In both cases supply installations can benefit from having a hydrophor installed. Installations represent a system of pumps connected to the network through "Kmp" vessels that are equipped with adequate automation. Devices for this purpose bear "HFm" marks on them.
Mode Of Operation
HFm devices are, prior to the start of operation and upon a completed assembly, filled with a gas up to the pressure set by the project as "preliminary pressure for filling". When the system is set into operation, the liquid with the pressure higher than this enters the vessel, raising its pressure to the pressure that the system itself is on at that moment. If this is lower than the required (set) pressure, the automation immediately sets the pumps into operation. The pumps then get excess water into the hydrofor vessel raising the pressure in it and when this is levelled
with the switching off pressure, the automation ceases their operation. Further exploitation is done from the water accumulated by hydraphor where, due to water losses, air expands and the pressure drops. When the pressure reaches the pump switching-on pressure, the automation switches them back on and the cycle is repeated. Vessels are connected to the network and placed behind the pumps and have not got separate drain pipe and supply-pipe. Their description is given in figure 3.
Application
HFm vessels are applied in installations used for transportation of liquid fluids especially in systems for supplying drinking and technical Water (other fluids on request), or where indicated
by projects, or when necessary.
Vessel Equipment
The vessel equipment consists of a connecting gate through which the vessel is being loaded and reloaded with air, a contact manometer, reinforced hose for connecting vessel to the panel,
control table and a membrane water level indicator. Control tables of hydrophor vessels are manufactured with automation for switching on (outgoing signal) two "A.H.F.2" pumps (one operational⁄one spare) and three "A.H.F.3" pumps (two operational⁄one spare). The pumps and the electric switchboards used for starting their operation, the armature as well as the connecting elements may, but need not, be delivered together with the hydrophor device.
Ordering
When ordering it is necessary, except in case of water, to designate the type of fluid, vessel (suction type⁄pushing type), size, nominal pressure and the required pressure for preliminary gas loading, type of automation (for two or three pumps) as well as the nominal diameter of the connector.
