Water motor driven foam pump proportioner.

Function principle and the importance of knowing the viscosity of the concentrate.

Function principle

A water motor-driven pump system is a mechanical way of dosing firefighting additives into the water, without the need of external power or pressure balance. 

FIREMIKS is such a system and it consists of two volumetric parts, one water motor and one concentrate pump, connected to each other through a direct drive coupling. Through the rotation of the pump drive, the concentrate is pumped into the water motor outlet, where dosing occurs. With this solution the water motor acts like a combined flow meter/drive for the foam pump, so automatically achieving the correct ratio between water motor and foam pump (= dosing rate within approved tolerances) without use of any external flow meters, valve regulating systems or orifices.

A water motor may either be a positive displacement (volumetric) type motor or an open turbine. The difference between these two options is that, with a turbine as drive, the flow and pressure range will be limited as a turbine motor is only partly volumetric,. Furthermore, with a Pelton type turbine a part of the water flow will be wasted.

FIREMIKS is a volumetric system with a positive displacement vane water motor instead of a turbine. The water motor rotor has 8 (or 10) working vanes, which gives an early and stable volumetric function of the water motor. The tight interior design, along with low friction vanes, reduces noise level and vibrations. All this makes it possible to maintain the mathematical ratio between water motor and concentrate pump in a wider pressure and flow range, furthermore all of the water is used for the firefighting and no water is wasted.

FIREMIKS can be installed anywhere between a water source (hydrant or main water pump) and one or several nozzle(s), (monitor, spray pipe, foam chamber, sprinkler head, low- ex, medium-ex or high-ex). It does not need a pressure tank; one only connect it to an atmospheric foam tank which can be replaced even under operation if necessary, using a simple valve switch. Such freedom of placement also makes it possible to design for the fastest possible reaction time – the closer to the discharge, the sooner the foam reaches the hazard.

The importance of knowing the viscosity of concentrate to choose the right type of foam pump.

Today the different brand and types of foam concentrate comes in a wide range of viscosities. To be able to select an appropriate proportioner one needs to know the viscosity of the concentrate and if it is Newtonian or non-Newtonian. 

Water motor driven foam pump systems equipped with Gear pump are particularly suited for use in systems with higher flow rates, such as deluge systems and large fire monitors. Gear pumps are also very suited for high viscosity concentrates. The Gear pumps are equipped with counter rotating gears that creates an even flow that doesn’t agitate the concentrate, furthermore the gears seal even better with high viscosity additives. Well-dimensioned and shortest possible suction line between foam tank and FIREMIKS is always an important factor to facilitate suction of high -viscosity concentrates.

Water motor driven foam pump systems equipped with Piston/plunger pumps are particularly suited for use in systems with low start flows, for example sprinkler systems. Piston pumps are also very suited for low and medium viscosity concentrates. Important to know is that Piston pumps have a limit upwards to high viscosity concentrates due to the Piston pump principle; for each revolution the plunger sucks concentrate and then presses it out and the concentrate goes from zero to full speed twice per revolution. If the static viscosity is too high with non-Newtonian concentrates, the concentrate will not flow smoothly and therefor the correct dosing rate might not be achieved.

FIREMIKS proportioners are offered with both types of pumps, Gear and Piston (plunger). Among several important factors, by them flow and pressure, we always collect info of the concentrate, incl viscosity, before we propose which type of pump we will offer our unit with.  

Both pump types can also be supplied in Mobile versions. With a Mobile unit (or installed in a Fire truck) a fire brigade can lay out a system consisting of one FIREMIKS proportioner and e.g. three, four or five nozzles working independently of each other, at different heights and lengths from main water pump.

FIREMIKS is available in different flow sizes, from max capacity of 150 lpm up to 10,000 lpm, and with fixed dosing alternatives of 0,5% 1%, 2%, 3%, and selectable 0,3-0,6-1% or 1-2-3%. Other dosing options are available on request.

Due to its comparable lower weight, compact design and no need of external energy, installation of a FIREMIKS is relatively easy compared with for ex. Bladder tanks system. It can, if requested, be supplied with a dosing return valve enabling regular tests without consuming any concentrate, an economically and environmentally beneficial option. FIREMIKS meets applicable parts of NFPA 11 and NFPA 1901 and production is made according to European directive 2006/42/EC = CE marked. A selected line of six sizes are FM-approved, incl. different water motor material: hard anodized and PTFE-coated ALU, Bronze or Stainless steel. We offer also Third-party inspection certificates from for ex. DNV-GL, towards NFPA 11 and/or EN 13565 for the whole range.

Some reference examples are Pertamina Oil - Indonesia, Rosenbauer Tunnel protection - Austria, Jotun A/S - Norway, W?rtsil?/Singapore Marine - Singapore, Port of Koper – Slovenia, DOW chemical – Netherlands, Engie Axima – France, La Farge – Serbia, Hexion GmbH – Germany.

For more information, go to www.firemiks.com

2020-01-18