Engineering the future
High pressure hose pumping under arduous conditions
Industries which transfer, sample and meter under arduous conditions, such as water and waste treatment, can rely on high pressure hose pumps for sludge thickening, filter-press, digester and centrifuge feed, and pit and lagoon emptying. These pumps capably handle caustic, lime slurry, floccants, ferric chloride, coagulants, active carbon, aluminium sulphate, magnetic, polyelectrolyte, sodium hypochlorite.
Bredel engineering created an en-tirely new type of pump, the high-pressure hose pump. Its patented technology attains high levels: the unbeatable simplicity, reliability and low maintenance needs of peristaltic pumping brought to high-flow, high-pressure duties. Today, nearly 50.000 of these hose pumps are working around the world solving the toughest pumping problems at flow rates up to 80 cubic metres/hour (350 US gpm) and pressures up to 16 bar (230 psi). Hose pumps are the future, and they are the fastest growing pump type.
What makes high-pressure hose pumps the fastest growing pump type?
- Easy to install and simple to operate, these hose pumps are rated for continuous use, 24 hours a day, 7 days a week.
- Abrasive slurries, corrosive acids, gaseous liquids and shear-sensitive products can all be pumped with confidence.
- Excellent ability to handle aggressive, high viscosity, high density products.
- Safe dry-running. The pump does not need fluid in the hose to cool or lubricate it, and can suck air intermittently or continuously without damage.
- Contaminating-free, the fluid is contained entirely within its hose, seperated from the pump.
- With no seals, valves, diaphragms, glands immersed rotors, stators or pistons to leak, clog, corrode and replace, the pumps are hygienic, easy to clean and virtually maintenance free. Spares inventory investment and management are dramatically reduced.
- The low rotor speed, resulting in low fluid velocity virtually eliminates cavitation and degassing risks.
- Reversibility and siphoning are eliminated, with no valves needed.
- Self priming, high suction lift for maximum flexibility of installation.
- Output is directly proportional to pump speed and independent of inlet or discharge pressure conditions or fluid viscosity, giving superb metering capabilities.
- The specially compounded food grade lubricant also functions as a coolant and makes these pumps especially quiet-running.
- At the heart of all Bredel pumps is a remarkable precision machined hose, available in abrasion and corrosion resistant materials, including natural rubber (NR), EPDM and corrosion resistant materials, including natural rubber (NR), EPDM and internationally approved food-grade BUNA N (NBR).
Industries handling visceous and abrasive fluids, such as ceramics, value the abrasion resistance, low levels of shear damage and absence of metallic components. Equally important is the ability to handle media such as ceramic slip without aeration; the hose pump’s glandess construction prevents air ingress during pumping.
Future of high-pressure
The all new SPX creates a new standard for hose pumping with its unique patented direct-coupled design wich combines the best features of conventional bareshaft and close-coupled designs. At the heart of the SPX direct-coupled design is a large diameter, high-strength, twin-bearing hub integrated into the pumphead. Uniquely, this means that the rotor is always fully, and centrally, supported by its own bearings, unlike a close-coupled design which relies on the gearbox bearings to carry overhanging pumphead loads. The SPX elimantes the coupling and baseplate of a bareshaft design, bringing its footprint and weight below that of a close coupled design. Maintenance and set-up time is drastically reduced. There is a choice of an ultra-compact planetary gearbox or conventional helical gearbox. For specialist drive needs such as petrol or diesel engines, a bareshaft version of the SPX is available. Hydraulic or pneumatic motors can easily be fitted to the standard SPX with an adaptor available from Bredel. The gearbox plugs directly into the pumphead, and a unique buffer zone has been created between the pumphead bearing and gearbox bearings, protecting both, and providing early warning of lubricant seal failure. Up to now, seal failure could resist in costly damage to the gearbox or the pump.
Industries which handle viscous slurries, shear sensitive and abrasive fluids, such as pulp and paper, have discovered the benefits of Bredel pumps for the transfer of clay slurry, talcum suspension and pulp, and the metering of adhesive, ink coatings, pigments and products such as titanium dioxide.
Industries dealing with abrasive and easily damaged media, such as brewing, have switched to these pumps on a wide scale because their glandless and valveless construction makes them ideal for sampling and precise metering and dosing. Bredel hose pumps handle diameceous earth at all stages of the filtration process, dose yeast into the wort prior to the fermentation vessels, feed settled yeast to filter presses, lush delivery lines and skim off the surface layers of unsettled yeast.
Industries which handle corrosive and toxic media with high specific gravities, such as mining, use Bredel pumps on a wide scale because of their resistance to aggressive fluids, and their ability to self-prime an run dry. Simple rugged construction and operation and maintenance ensure that these pumps thrive in the toughest pumping application. The pumps are used in the transfer of nickel and coal slurries, and the metering of pyrite slurry, acids cyanide, grout, thickener underflow and drain cleaning.
- uneven external surface of the hose prior to matching
- precision machined natural rubber outer layer
- four nylon reinforcement layers
- inner liner material available in various chemical resistant rubbers.
At the heart of all Bredel pumps is a remarkable patented composite reinforced hose. The hose is constructed from high quality compounded rubbers, reinforced with four layers of braided nylon and finished by high precision machining. Because rubber is incompressible, nothing is more important to hose pumping than accurate control of occlusion:
- over-compression of the hose stresses both pump and hose. A 1mm variation in wall thickness would reduce hose lift by at least 25% and impose unplanned loads on the pump beaings, reducing both hose and pump life.
- under-compression results in loss of pump efficiency and damaging backflow which also reduces hose life.
Each Bredel hose is a precision machined component, with unmatched wall thickness and surface finish accuracy ensuring that perfect occlusion is maintained and hose life is maximised. It is the only hose pump manufacturer to machine its own hoses. Machined hoses give consistent tolerances, quality and shimming; improved hose life - due to reduced friction. On the other hand four layers result in an excellent suction performance; in high pressure capability; volumetric accuracy; conistent capacity tolerant to varying suction and discharge conditions; and exceptional performances when handling high viscosity products.
Natural rubber: a highly resilient first choice material with excellent abrasion resistance and mechanical strength, is generally resistant to diluted acids and alcohols. Maximum liquid temperature 80 °C, minimum temperature –20 °C.
Buna N (NBR) Acrile Nitrile Butadiene rubber: FDA and 3A approved. A highly abrasion proof and wear resistant material that is generally resistant to oils, fats, alkalines and detergents and is suitable fo a wide range of food applications. Maximum liquid temperature
80 °C, minimum temperature –10 °C.
EPDM: excellent chemical resistance especially to concentrated acids, ketones and alcohols. Maximum liquid temperature 80 °C, minimum temperature –10 °C.
Discharge Pulsation Damper: this hose pump accessory operates in the discharge line by means of reinforced flexible hose within a steel cylinder, surrounded by a volume of compressed air. The damper unit can also be used as a pressure relief and injection valve. The pulsation damper advantages include: elimination (up to 90%) of the pump discharge pulsations; protects pump, pipeline and instrumentation; reduces pipe vibration, hammer and noise; increases pump performance and hose life; increases efficiency of the pump installation; non intrusive, through bore easy to clean; simple installation, can be mounted horizontally and vertically; flanged connections in accordance to DIN, ASA/ANSI or JIS.
The installation of the inlet pulse accumulators on the suction side is only recommended to eliminate the impulse losses and achieve optimum hose life. Where the inlet line lengths and pump speed warant its use, the pulse suppressor asssembly must be mounted against the pump inlet flange in the vertical position. Findings show that positive and negative pressure spikes in the suction line during pump operation can be effectively eliminated… resulting in quieter operation and extended hose life. The lubricant level control will switch off the pump in case of high liquid level. Should a pump hose fail, the product will be contained within the pump. The lubricant level control sensor plugs directly into the breather and senses a high lubricant/product mixture level inside the housing, that activates a contact relay which switches off the pump. An option of a low lubricant level sensor is also available. Clean in place (CIP): The models 40 and 50 are also available with the option of retracting shoes for non-intrusive cleaning, for CIP-applications. Vacuum assist: For absolute suction conditions and high viscosity fluids. The hose pumps also have the option of vacuum assist to aid hose recovery and increase hose fill capacity.
The engineering challenge…
Until now, the choice in high-pressure hose pumps has been between bareshaft (long-couped) and close-coupled pumps. Bareshaft pumps have lower maintenance needs, and fully protect the drive. Close-coupled pumps are more compact and do not have the cost of a coupling or the need for drive alignment, but the gearbox gearings take all the forces of the pump and the gearbox seals must resist the pressure in th pump casing. The worldstandard Bredel SP pumps have always used bareshaft construction because this has been the only way to ensure complete reliability and the lowest maintenance needs and cost. Now, the new direct-coupled design combines the best features of both designs. The size and simplicity of a close-coupled pump with the reliability and ease of maintenance of a bareshaft design. No other hose pump combines such a small footprint with a fully protected drive. The gearbox actually plugs directly into the pumphead, creating an innovative buffer zone that provides additional protection to the pump bearings and gearbox. Simpler hose clamping combined with a powered hose-changing system cuts hose replacement time, and no special tools are required. Access to the case is faster, and corrosion resistance has been improved throughout the design. Uniquely, in the event of massive overload from a stalled rotor, a computer-calculated undercut shaft will fail safely and predictably, minimising component damage and downtime.
Erik Achten Associates