The object of application: Aspiration from tanks of wastewater with suspensions resulting from electroplating and galvanic processes.
The company has the need to aspirate from underground tanks various wastewaters arising from their production process. These fluids in addition to maintaining a variable chemical aggressiveness (but always consistent), are also characterized by the presence of metallic particles accumulated during the various manufacturing processes. In the past were used pumps of various types, centrifuges, pneumatic membrane also submersibles. No pump previously used, has never solved the problem. For one reason or another, when you had the need to pump out some decanting, the pump designed was broken, does not prime, clog, worked well until the time but not now. It should be keep in mind that the nature of the fluid, as well as corrosive due to presence chemicals necessary to pre-treatment, also has the metal micro deposits.During the electroplating operation , the preparation of the products to be treated also provides cleaning cycles with acids and alkalines fluids that serve to improve the quality of the galvanic final treatment. In these baths that focuses a good part of the metallic particles. The combination of chemical corrosion and metal abrasion , creates a wastewater mix very damaging for the pumps, see why:
centrifugal pumps have their weak point in the system hydraulic sealing, constituted by the mechanical seal or rubber rings. The sealing system is resistant to chemical corrosion, but not against abrasion. After indefinitely time, but always too short the sealing system yields and the pump fluid releases can attack components not protected against contact of electroplating aggressive liquids.
The centrifugal pump as well, must be used below the level of the liquid to run correctly, poorly adaptations of a general service centrifugal pump is not a good choice. Also is not suitable for fluids transfer of high viscosity media as sludge is.
But the sludge is generated, and must be removed in some way. The centrifugal pumps exist also in version self-priming, and are much more suitable to treat galvanic wastewater with suspensions or slurries dissolved.
The times of priming of a self-priming pump are long sometimes up to 15-20 minutes, if the pump takes air suction for some unfortunate reason, the pump must be re-primed, with consequent waste of time. When the levels in the tanks are minimal this phenomenon is guaranteed.
The centrifugal pumps run fast (2800 revolutions per minute) the sealing organs responsible to the barrier of the liquid, suffer for this reason, a strong abrasion occur due to the action of the rotation speed mixed to presence of particulate abrasive metal. In a relatively short time the pump loses its suction capacity and it will be necessary to set in on maintenance of the pump. The pump must be completely removed to replace the sealing device, often this type of intervention is carried out by specific repairers in external workshops, this operation is not economically insignificant.
Let us come to the double diaphragms pneumatic pumps , cost perhaps less than all of the other, but beware, if you accept the cost of compressed air handling (considerable on balance).
The limited cost of purchase in relation to other pumps, attracts a lot. Diaphragm Pumps work quite well, better of centrifuges.
The limit in these pumps consists in the fact that there is a valves system to operate, especially in the suction phase and priming, all work fine in the presence of normal fluids. The situation changes in presence of wastewater with solids. The valve system no longer provides a linear operation, when the valve does not work in a perfect way the pump loses the ability to prime and must be re-primed again. Are rather noisy even if this is a problem. The real problem is absence of preventive maintenance, when diaphragm breaks, the the galvanic aggressive fluids spill out into the distribution system creating damage such as to have to replace it completely.
A solution for electroplating and galvanic wastewater, the peristaltic pump Hose Carrier.
A few years ago that company purchased a HCP 35 peristaltic pump, always in use, without too many concerns , even for reasons different from original needs . Once every year and a half, one tubular membrane is purchased and replaced internally at low costs.
More information on the Pump Hose Carrier HCP 35