For many types of pump, liquids with abrasive particles in suspension can be difficult to handle because there is always the threat of wear at seals and other vulnerable surfaces. Hydra-Cell pumps can be found in numerous industrial processes involving transfer of liquids containing particles – often replacing pumps such as screw and progressing cavity pumps, with improved process reliability.

The Hydra-Cell offers a unique combination of features, making it generically different from other types of pump. There are no dynamic seals in the pump. Multiple diaphragms are integrated in a single compact head, flexing in sequence to produce smooth positive-displacement pumping action. Hydraulic balance enables the diaphragms to operate without stress, even at high pressures for a long, reliable life.

These features are combined with high energy efficiency, gentle handling, simple build, undemanding maintenance and easy electronic control.

The pumps can run dry without damage – indefinitely!

See below for application examples from information supplied by customers.

• Carbon black manufacturing
• Ceramic filter press
• Membrane filtration: flexible pump performance contributes to wide operating range of pilot plant
  Tank cleaning with recycled solvent

For more information regarding either seal-less pump, mixing systems or chopper pumps, contact us at:
www.monitorpumps.co.za email: grant@monitorspray.co.za or +27 11 618 3860

• Pumps water with particles
• Run dry capable
• Very low operating costs

Dust-filled air can be a major environmental problem causing discomfort for people living and working near quarries. Created when crushing or transporting bulk materials, this problem can be easily solved by spraying the dust with very fine water droplets, specifically where the dust is created. In this way, operators can stay within the constraints of occupational health and safety and environmental protection. Hydra-Cell pumps play a crucial role in bringing down the cost of dust suppression.

Applications areas:

Hydra-Cell Solutions
Hydra-Cell high-pressure, seal-less pumps power fugitive dust suppression, water fogging systems without the use of compressed air and the costly equipment used to generate it. They also help minimize water usage ensuring a drier working environment. Hydra-Cell pumps provide a virtually pulseless flow of up to 138 lpm (36.5 gpm) at pressures up to 83 Bar (1200 psi) in order to serve systems with numerous spray heads. (Some models can operate up to 172 Bar (2500 psi)).

High reliability

• Designed for continuous or intermittent use
• Extended service intervals
• Operator proof… can run dry without damage
• Can pump grey/recycled water without the need for fine filtration.

Economical
Hydra-Cell high efficiency, direct displacement pumps reduce power requirements while generating virtually pulse-less water flow. Hydra-Cells true positive displacement pump action ensures very high efficiency. eg 30 lpm at 30 Bar power required is 2 kW. The seal-less design ensures high reliability, keeping maintenance cost to an absolute minimum.

Safe
Hydra-Cell’s design allows pump shaft speeds to run from 10 rpm to 1450/1000 rpm and discharge pressures to range from 1 Bar to 70/172 Bar.

Low servicing costs

• 6000 hours oil change intervals under normal conditions
• Quick to service
• Low cost of service parts

For more information regarding either seal-less pump, mixing systems or chopper pumps, contact us at:
www.monitorpumps.co.za email: grant@monitorspray.co.za or +27 11 618 3860

Model D/G-10 (shown) is one of several multiple diaphragm Hydra-Cell pumps used in the OSB industry. Depending on the model, Hydra-Cell offers maximum flow rates ranging from 30 to 130 L/PM and pressures from 68 bar to 170 bar.

A leading Oriented Strand Board (OSB) manufacturer chose gear pumps to deliver resinous glue containing particulates into a mixing chamber, where it is sprayed onto wood fibers in the early stages of the manufacturing process. Chosen for their high-pressure capability, these pumps leaked persistently through their mechanical seals, damaging the gears when hardened resin became trapped between closely meshing gears. The pump and gearbox had to be replaced three times in one month.

Installing a Hydra-Cell pump immediately solved the problem by providing reliable, high-pressure pumping of the resinous glue. The seal-less design of Hydra-Cell means no dynamic seals to leak, wear, or replace. Spring-loaded, horizontal disk check valves in Hydra-Cell enable the pump to process liquids containing particulates up to 500 microns or greater diameter.

After six months of trouble-free operation, the second pumping system was converted to Hydra-Cell with the same successful results for the Oriented Strand Board manufacturer.

Trends

• Increase use of powdered cleaning chemicals to reduce cost
• Use of recycled water to reduce cost
• High water temperatures to improve cleaning

All of the above can cause increased expensive maintenance for Piston pumps with Dynamic seals.
Hydra-Cells Sealess design means that this dynamic seal maintenance can be eliminated.
The Hydra-Cell pump can also run dry.

Hydra-Cells multiple diaphragm pump head delivers “virtually pulse less” flows.

Potential saving of R6,600 per year per pump

In producing compressed air only 10 to 20% of the electrical energy input reaches the point of end use. “Best practice for Compressed air systems” 2003. The remaining energy is lost through wasted heat or leakage.

So every 5CFM of air generated takes approximately 0.74KW of electrical input.

Other savings include no pulsation damper required.

Hydra-Cell can show significant financial savings.

Converting organic waste material into re-usable energy is an important part of the governments
overall strategy for achieving targets for zero food and packaging into landfill by 2015.

Anaerobic digestion systems are increasingly playing a key role in this process and SYSTEM MIX Ltd have provided specialist knowledge and expertise to a number of the UK’s water utility companies. One recent example is an Advanced Digestion project where System Mix Ltd were awarded the contract to design, manufacture and install suitable mixing systems for 4 anaerobic digesters at Dwr Cymru Welsh Water wastewater treatment works located at the Cardiff and Afan. The award of this contract followed many months of design and development by Systems Mix in conjunction with the Vaughan Pump Company, who developed the patented Rotamix system.

The main objectives:

The main design remit for these mixing systems was to provide 94%+ active volume mixing within the two sizes of digester proposed. Afan STW digesters required a working volume of 4300m³ with geometry of 17.8m deep x 17.2m Ø; the Cardiff digesters required 6500m³ with geometry of 20.2m deep x 20.2m Ø; while all digesters were to be new build and constructed from concrete.

The feed to these digesters is hydrolysed sludge from the Cambi process and expected to be fed into at a minimum of 10% DSC (Dried Solid Content). The requirements set by Welsh Water and by contractors Imtech Process, was to achieve a homogenous mix of the resulting digestate with a minimum of 94% active volume. System Mix and Vaughan; using CFD (Computational Fluid Dynamics) analysis, developed the design and provided detailed data to all parties showing that the mixing systems offered would achieve this requirement and furthermore, backed this up with a 10 year process warranty.

Part of the design solution required by Welsh Water and contractors, Imtech Process, was to have the internal mixing system in a format that would allow the installation and removal of mixing nozzles without the need to empty a digester, stop or interrupt the digestion process nor loose gas during this operation.

A simple yet highly effective system:

The principle of the system is simple as System Mix Ltd have designed and patented the ‘Drop-In’ Mixing Lance system that has a gas sleeve that seals with the top fluid level, allowing lance assemblies to be inserted and withdrawn without losing gas pressure. Lances are inserted through the roof of the digester and locate on docking cones permanently installed on the floor of the vessel. These docking cones locate each lance; stopping deflection and ensuring correct alignment for optimum mixing efficiency. Nozzles are strategically placed along the lance to create the Rotamix Dual Zone mixing action; lower nozzles create rotation around and across the floor area whilst high level nozzles accelerate upper sludge volume inducing a coriolis effect which drafts high level sludge back down to the central suction points. Sludge is drawn out through the suction point to the Vaughan Chopper pumps which are located outside the vessel at ground level. The Vaughan Chopper Pumps are at the heart of all or digester mixing systems and each lance is powered by its own Vaughan Chopper pump ensuring that there is always mixing, even when a unit is out for maintenance.

The development of these high performance mixing systems is due mainly to the inclusion of the Vaughan Chopper Pump. These robust and reliable pumps condition the sludge as it passes through the impeller cutter area and this reduces solid size as well as preventing reweave agglomeration of fibrous content. The continued conditioning of sludge enhances bio digestion as well as reducing the problems of rag mass downstream in the process.

Drop-in lance enhances process:

Using Drop-In Lance mixing systems has been a significant development in digester mixing technology, these lances allow for easy removal and installation. This facility offers users greater flexibility for future enhancements by adding advance pre-digestion process like Hydrolysed Sludge Treatment of Pasteurisation as well as increases in dry solids loading, with little disruption to the biological process. The ability to maintain internals without needing to drain and enter the vessel removes the significant cost of disposing of high volumes of sludge.

Once the design of digesters was approved by Imtech Process, System Mix engineers produced detailed 3D drawings of the systems for them to include within their design package. Construction of all 4 digesters (2 at Afan and 2 at Cardiff) were completed by Morgan Est. and Imtech on time, early April 2010 and mixing systems for each were delivered in accordance with the agreed contract dates.

System Mix supervised the installation of lances into each digester; the two digesters at Afan were installed in one day and Cardiff within two days from first lift, with an average installation time of only 4 hours per vessel.

System Mix designed and installed a similar system into digesters at Anglian Waters’ Kings Lynn STW, adding credence to designs and methodology. The Kings Lynn digestion has the most productive and efficient digester and this helped convince Welsh Water that System Mix was the right solution for these applications. These successes, in addition to the standard designs installed at other advanced digestion schemes at Cotton Valley, Great Billing, and Bran Sands and Frameworks held with Southern Water, has significantly increased the awareness of these systems. This has established System Mix as an important supplier of digester mixing technology to the Anaerobic Digestion industry, not only in municipal applications but also in the rapid growth area of Bio Waste Industry.

A summary of the benefits:

The features and benefits of System Mix are; retained digester volume and minimal settlement, with over 90% being retained during its working life, maximised solids reduction, continuous recirculation during mixing ensures full distribution and breakdown of solids, both mechanically and biologically, retained gas production is maintained to levels seen at system start without drop-off, minimal cleanout costs as the digester can be easily cleaned at minimal cost. And finally, low installation costs as all rotating equipment is externally mounted and internal equipment is easily installed.

Reducing costs associated with unplanned maintenance and achieving significant savings on energy consumption were the important benefits achieved at a Severn Trent Water facility, following the installation of Vaughan Chopper Pumps, supplied by P&M Pumps.

The Sewage Treatment works at Netheridge in Gloucester had experienced problems with existing pumps which were continuously blocking and also suffered from leaking glands. The application was pumping raw sewage from 20 m below ground from wet wells to the inlet works. To complicate matters the pumps were housed in a dry well which was subsequently classified as a ‘confined space’ and this requires operators to have breathing apparatus escape sets to meet health and safety requirements. Therefore, when contractors were called in to regularly unblock the original pumps maintenance costs escalated further, in the region of £100,000 for one year.

Initially, Severn Trent Water operated one Vaughan Chopper pump on a trial basis for an extended period to see if it would meet the challenges of the demanding application and this pump is still used as a stand-by on VSD Drive. Following the successful trial, additional pumps were installed and the process now involves a total of four Vaughan Chopper pumps operating continuously at a fixed speed. The pumps are 12 in discharge PE12U’S with 90Kw, 970 rpm motors.

Jeff beddall, a work flow technician at Netheridge Treatment Works comments, “We have achieved significant savings on labour and electricity consumption, the problems we were experiencing of blockages and leaking glands with the original pumps have been eliminated, following the switch to Vaughan Chopper Pumps”. Jeff added, “We particularly appreciate the fact that the pumps do not block, one pump has already been installed for just over three years running 24/7 and it has never blocked”.

Through their experiences at numerous UK waste water treatment sites, P&M Pumps have been able to demonstrate that Vaughan Chopper Pumps can bring significant cost-savings. In most cases, retrofitting a Vaughan Chopper Pump into a problematic area improves the whole process and will be self-financing, with payback periods of less than one year, thereafter minimising the effect to the budget holders.

TWAS can be much harder to mix than primary sludge, leading to disappointment and redesign. Computer simulation combined with a viscous sludge fluid model came to the rescue.

By Jeff McCormick, Carollo Engineers; Richard Bishop, CH2M Hill Engineers; John Peterson, Clark
Regional Wastewater District; and Glenn Dorsch and Marilyn Pine, both of Vaughan Company, Inc.

The Vaughan Rotamix® mixing system for the blend tank at the Salmon Creek Wastewater Treatment Plant, Vancouver, WA, should have had plenty of mixing flow for stirring up the sludge considering the relatively small size of this tank. Rotamix® is a hydraulic jet mixing system with floor-mounted nozzles powered by a Vaughan Chopper Pump. The Rotamix system replaced a troublesome propeller mixing system in this tank. The blend tank is used to evenly mix primary and other sludges before they are pumped into the primary anaerobic digester. And yet the treatment plant was calling to report that the mixing system provided was not working to their satisfaction. They were seeing no upper surface mixing once the tank level got higher than about 6-8 ft. in this 23′ dia. X 23′ high, 70,000 gallon cylindrical tank. While the system worked “like a Jacuzzi” when mixing sludges that flowed similar to water, investigation by several Vaughan and consulting engineers and Vaughan’s process specialist revealed two primary problems: (1) the polymer thickened waste activated sludge (TWAS) going into this tank was much more viscous than anticipated, and (2) TWAS, which floats, was being added through a standpipe located above the upper surface of the sludge in the tank, leaving the TWAS unmixed at the top of the tank.

To find solutions to this dilemma Vaughan Co, the mixing system supplier and an experienced user of ANSYS CFX, modelled the tank and mixing system using a fluid model developed from sludge rheology data provided by a treatment plant in England. Vaughan Co. was uniquely prepared for this challenge, having modelled in excess of 700 large tank mixing systems using CFX, a computational fluid dynamics (CFD) computer program that simulates complex fluid flow. Many of these systems have been modelled with non Newtonian fluids, such as sewage sludge. Within a few weeks eight different trials had been run showing that the system mixing velocity could be doubled by using the same pump, motor and mixing flow but by changing: (1) the number of mixing nozzles from two to four, (2) rearranging the nozzle angles to spread out and better distribute the momentum around the tank, and (3) lowering the sludge standpipe so that TWAS was dumped into the tank as close as possible to the nozzles.

The customer, understandably concerned after the first disappointment, wanted to know how the modified system would work with his sludge before any changes were made. To do this, Vaughan needed detailed data on the actual Salmon Creek blend tank sludges. Fortunately, an enterprising CH2M Hill engineer on this project was willing to use the plant’s viscometer to obtain detailed shear stress vs. strain rate data for the different sludges blended in this tank. This data allowed Vaughan Co. to create a more accurate fluid model to use in the CFX simulation. This fluid model allowed for a much more realistic simulation of the original and the proposed mixing systems for comparison. The original mixing system with 2 single nozzles is shown below.

The improved mixing system with 2 dual-nozzles and additional tank detail is shown below.

The following graph illustrates the special problem confronted when simulating viscous fluids in mixing systems compared to that encountered in pumping/piping systems.

Fluid viscosity is related to the shear stress vs. shear rate curve shown above. Each plant’s sludge, which is a non-Newtonian fluid (water is Newtonian), is going to have a unique curve. Of particular importance is obtaining enough data to construct an accurate curve. Data on the left side of the curve is especially important because of its impact on mixing systems. The shear stress vs. shear rate curve for the Salmon Creek TWAS sludge is shown below.

Data for the various sludges in the blend tank are characterized by the table on the following page. Note that the “K” coefficient for the TWAS is 29 times higher than the same coefficient for unthickened primary sludge coming out of the clarifier. This illustrates how extremely viscous the TWAS is compared to another typical sludge.

The originally installed system was simulated using the TWAS sludge fluid model. Top and cross-section elevation contour velocity plots are shown below, illustrating that the system was not providing good mixing velocities with this worst-case sludge except near the tank floor and the nozzles.

The contour velocity plots of the modified system with 100% TWAS fluid are shown below, showing that while the system still won’t generate surface movement when completely full, the system is working much better, providing surface mixing velocity at about 15′ of liquid level compared to about 6-8 ft. with the original system.

The modified system mixing a blend of TWAS and primary sludge provides much more impressive mixing results, as shown in the top view and cross-section elevation contour velocity plots on the next page. This blended sludge is much less viscous than 100% TWAS modelled on this page.

In response to Vaughan’s CFD modelling the treatment plant officials agreed to the proposed system modifications. They were now more confident in the design changes since the simulation of the original system accurately described what they were observing.

Vaughan provided the materials and labor to make the system changes after the owner drained and cleaned the tank. The tank was out of service for less than one day because of excellent cooperation between organizations. After the mixing system modification, the physical mixing results essentially matched those predicted by the CFX simulation in 100% TWAS. Mixing was visible at the upper surface of the tank with levels all the way up to about 15 ft. high. At higher tank levels less upper surface motion was evident. Still, the plant operators understood that even if upper surface motion was not evident at the highest levels with the worst-case viscosity TWAS, mixing was still taking place throughout the lower two thirds of the tank.

CFX, combined with good teamwork between the equipment supplier and the consulting engineer, allowed Vaughan Co. to simulate a host of mixing system changes using various realistic fluid models while rebuilding customer confidence that the system could be made to work to their satisfaction. All this was done before any physical work was performed on the tank or mixing system. This approach saved considerable cost and generated significant good will between customer and supplier.

One of three Spraying Systems automatic tankwash units is lowered into working position at Atchison Topeka. The Hydra-Cell G35 seal-less pumps feeding these units with hot liquid at 70 bar pressure are still in daily use after six years service.

Only one major problem threatened to spoil the picture. Piston pumps delivering high-pressure hot water to spray heads repeatedly broke down. Seals and other vulnerable components continually had to be replaced. Inside a year, Atchison Topeka scrapped the unsatisfactory pumps, replacing them with new piston pumps from another manufacturer. However, recalls operations director Andy Hartwell: “The new pumps cavitated so much that the vibration nearly shook the building down”.

It was the company’s founder and managing director, John Chandler, who found the solution – almost by chance – during a visit to France. At a busy tanker servicing depot near Rouen he spotted a battery of high pressure pumps serving a multi-bay tank cleaning installation.
They were pumps of an unfamiliar type the Wanner Hydra-Cell: seal-less units in which the pumping action is provided by pressure-balanced hydraulically actuated diaphragms. Their quiet performance and good report from the French depot management led him on his return to contact UK distributor CT Technical Products, now part of Roxspur Measurement & Control.Hydra-cell pumps are manufactured in a range of flow capacities up to 128 l/min, with pressure capability of 70 bar or higher, depending on the model chosen. Common to all model are seal-less design, energy efficiency (80% plus) and linearity in terms of flow and pressure. Flow is precisely proportional to pump speed and is not affected by changes in pressure. There is a wide choice of pump head materials and elastomers to suit many different applications.

For Atchison Topeka, CT recommended the Hydra-cell G35 model, with materials specification (such as high-temperature Buna diaphragms and hardened stainless steel valves and seats) to suit the particular system requirements of the internal tank cleaning operation. The G35 has a maximum flow of 128 l/min and is rated for continuous operation at 83 bar. Two of these pumps are used to deliver high temperature water at 70 bar pressure to three Spraying Systems automatic wash units.
After 6 years the original Hydra-Cell pumps are still in daily use. Maintenance requirements have been modest and the pumps have performed equally well with hot detergent solutions and with very hot water alone.

The Worcester facility not only handles ‘home-base’ cleaning of Atchison Topeka fleet, it also cleans tankers for outside clients, but always within the food industry. The company’s own vehicles carry a wide variety of food products including chocolate, jam, sugar, milk and glucose, with some of the tankers designed for solid product such as milk powder and flour. Part of the fleet is dedicated to single-product work, but most tankers are multi-functional within the food sector.
Tank washing routines are programmable – different products may need longer or shorter times, for example – but the average facility throughput is 10 vehicles each day.
While the automatic washers clean inside the tankers, the outside is washed by high-pressure spray gun. For this purpose, a third Hydra-Cell pump, model G25, delivers a detergent solution at 70 bar pressure and is also used to feed a pipe cleaning attachment.
Though not qualified for hygienic duties, Hydra-cell pumps are widely used in the food industry because of their seal-less design, high pressure capability and ability to handle particulates, abrasives, corrosives and hot liquids.Process products pumped include cocoa mass, liquid chocolate, lecithin, liquid nougat, sugar solutions, soft drinks concentrates and palm oil and salt mixtures. They are also extensively used in cleaning applications, pumping hot or cold (sometimes recycled) waster at pressure to feed CIP systems and hand-held washdown guns from ring mains.

Pumping at the heart of synthesis

A major chemical manufacturer settled on a Hydra-Cell G-10 pump to feed Butyl Acrylate into a reaction vessel. Butyl Acrylate is commonly used in the organic synthesis of various polymers and acrylic resins used in solvent coatings, adhesives, paints etc. Although water-like at ambient temperature, butyl acrylate polymerizes readily when heated and the fumes given off can be hazardous.  A stainless steel G-10 fitted with Teflon diaphragms now provides the sealless, low shear, steady delivery required by this demanding application.

PUMP: G-10IKSJSNEH
PLOW: .1 – .5 GPM (.38 – 1.9 LPM)
PRESSURE: 100 – 200 PSI (7-14 BAR)
SUCTION PRESSURE: 3 PSI (.21 BAR)
DUTY CYCLE: 24 HRS/DAY, 6 DAYS/WEEK