Pumps rise to challenge of corrosive materials

Paul Boughton

Advanced hardware and software are enabling modern pumps to tackle highly corrosive materials, yet require minimum maintenance. Sean Ottewell reports.

In what the company describes as a 'no-valve metering revolution' Watson-Marlow Pumps Group has launched its Qdos 30 pump range. Developed in response to extensive industrial customer feedback for improved chemical metering, the Qdos 30 eliminates ancillary equipment, enhances productivity, and reduces chemical waste through more accurate, linear, and repeatable metering than typical solenoid or stepper driven diaphragm metering pumps.

It delivers a 5000:1 flow range from 0.1-500ml/min and 7bar while integrating easily through IP66 manual, analogue, and Profibus control options. Featuring patented ReNu pumphead technology, Qdos 30 is fully sealed for safe, tool-free maintenance.

This means that fluids that are caustic, abrasive, viscous, shear-sensitive, gaseous, are slurries or contain suspended solids, can be safely and securely handled (Fig. 1). Advanced control features include fluid level monitoring, fluid recovery, line priming and intuitive flow calibration.[Page Break]

The pumphead can be configured on the left or right, making it ideal for installing in restricted environments or on skids, while its sealed design and fluid recovery eliminate wastage and ensures operator safety. Operation is intuitive via a menu-driven interface with a 3.5-in TFT colour display, providing high-visibility status indication. The keypad and display are positioned for easy access, along with input and output connections.

Featuring all-new hardware and software, applications for Qdos 30 include: disinfection and pH adjustment of drinking water and industrial process water; flocculation; industrial cooling water preparation; and reagent dosing in mineral processing to name but a few.

Maintenance intervals are up to six months at typical usage, reducing the impact of process downtime. In addition to the Qdos 30 Universal+ pump, four other variants are available.[Page Break]

Meanwhile Bredel, which is part of the Watson-Marlow Pumps Group, has launched three new hose pumps. Designed to suit all dosing, metering and transfer applications from 2.8 to 1200l/h across a broad range of applications, the new APEX pumps have no expensive wearing components such as seals, valves, membranes, stators, rotors or glands (Fig. 2). Subsequently, they are ideally suited for handling difficult fluids - abrasive, corrosive, viscous, shear-sensitive, crystallising - or even fluids presenting a combination of these properties.

Offering what Bredel describes as the best performance available on the market for pressures up to eight bar, along with reliable and stable flow up 1200l/h (with 20mm diameter hose), makes APEX first choice for ongoing, precise dosing. This is boosted by a new generation of long-lasting hoses that also supports repeatable accuracy when dosing additives, while continuous pump speeds up to 100rpm provide a wider capacity range in comparison with alternative hose pumps.

Bredel says that users of the APEX pumps benefit from extremely low maintenance requirements, giving extended uptime and process continuity. With cast aluminium housing providing superior heat dissipation, robust direct-coupled technology and precision machined hose elements, APEX provides decreased cost of ownership, reduced operating costs and low inventory stocking.[Page Break]

Among the many benefits of the new pumps is ease of scalability. While APEX offers optimum performance for low flow transfer applications, should process requirements change, easy upgrades are achievable without having to buy a new pump. This is because APEX models are three pumps in one, with a single pump body adjustable for three hose sizes (10, 15 and 20mm) when production volumes rise.

Hydra-Cell seal-less, high pressure diaphragm pumps have been available for some time with the fluid end machined from Kynar PVDF, a high temperature engineering fluoropolymer with high purity and outstanding resistance to a wide range of aggressive, corrosive chemicals, notably concentrated sulphuric and hydrochloric acids.

Now, Wanner International is able to offer these pumps with stainless steel DIN flange fittings and Kynar mating surfaces, making Hydra-Cell pumps even easier to incorporate into corrosive fluid systems.

Kynar liquid heads are available for Hydra-Cell G03, G10, G20, G25 pumps covering a range of performance from 3.79l/min to 76l/min at pressures up to 24bar (350psi) and are also available on the Hydra-Cell metering pump range.[Page Break]

Exceeding the performance requirements of API 675 in terms of repeatability, linearity and steady state accuracy, the Hydra-Cell pump's multi-diaphragm configuration generates virtually pulse-less flow, removing the need for dampeners in most applications.

Wilden has released its HX400S high-pressure air-operated double-diaphragm (AODD) pump, designed for use in applications that require the reliable transfer of viscous, solid-laden slurries at high discharge pressures.

What differentiates the HX400S AODD pump from competitive models is that, rather than relying on costly external boosters or amplifiers, one of the pump's liquid chambers is used as an amplification chamber. This allows the pump to generate a 2:1 ratio of discharge fluid pressure to air inlet pressure, resulting in the ability to achieve a discharge fluid pressure of up to 17.2 bar.

Additionally, the HX400S pump, which is available with 11/2-in (38 mm) inlet and discharge connections, is outfitted with Wilden's standard-setting Pro-Flo X air distribution system (ADS). The Pro-Flo X ADS features a state-of-the-art efficiency management system, which allows the operator to dial in the actual operational parameters regardless of the application demands or pump size.[Page Break]

The new Busch DS series COBRA vacuum pump range has a 20 per cent smaller footprint than the previous generation, and has superior powder handling capabilities resulting from their unique screw pump design. These vacuum pumps target high capacity load lock and harsh process vacuum applications in the solar market, as well as flat panel manufacturing applications. Designed to meet industry needs for the rapid cycling of big chamber pump downs and large volumes of hydrogen during solar cell manufacturing processes, the DS series range meets these pumping requirements in a powerful, cost-effective modular system.

The new vacuum pump models also come with options that address specific harsh process issues and energy saving requirements - 30 per cent energy savings are possible. One of the recent additions to the option catalogue opens the door to a cost efficient solution in difficult processes such as zinc oxide chemical vapour deposition, avoiding costly trap technologies.

The new frame design, with its separate booster and screw pump frames, allows for easy installation and maintenance.

Graco's new EP Series hose pump design uses a single, oversized roller that compresses a low friction hose through a full 360° rotation. This innovative design puts 40 per cent less stress on the hose compared to conventional shoe pumps running at the same flow rate. This results in a longer hose life when pumping corrosive, abrasive or sensitive materials for chemical metering, plating or yeast applications.

The pump also has 50 per cent more fluid flow per revolution than C-shape positive displacement pumps. Other features include a compact footprint for tight spaces. [Page Break]

33 per cent more continuous flow

The new Verderflex Dura 45 peristaltic hose pump is the latest addition to the Verderflex Dura family of industrial peristaltic pumps. The pump gives 33 per cent more continuous flow than other pumps in its class, lowering the cost of this technology.

Other new features include: operation up to 16 bar; motor supported independently of the gearbox; drain channel protects gearbox in case of a hose burst; shimmable rotor shoes for precise control of discharge pressure and optimum hose life; ringfeder slip bush protects against a stalled rotor; fully supported rotor shoes; simple flange assembly reduces hose change downtime; and competitively priced with standard selections including the latest hi-efficiency motors.

A number of hose materials are available, including nitrile rubber and ethylene propylene diene monomer (m-class) rubber.

By design, the peristaltic pump is ideal for the dependable handling of abrasive, corrosive, viscous, high density and high solid content fluids. It thrives in those applications where other types of pump fail. Water and waste water industries, mining and chemical processing are all prime markets for this workhorse. But being equal to the tough demands of these applications is far from its only strength. The peristaltic pump can also be extremely versatile.

"Perhaps somewhat overshadowed by its dominance in heavy-duty slurry and sludge handling, is the peristaltic pump's eminent suitability for handling shear sensitive products. It has a smooth, squeezing action that makes it ideal for use with flocculants, sensitive polymers and fragile cell cultures," added Verderflex.

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