Fig 1: Efficient and low-maintenance systems, like the EcoTrans MULTISAFE® pump from FELUWA, are required in process engineering industry in order to fulfil the plant operators’ current and future demands. Picture: FELUWA

The EcoTrans MULTISAFE® pump from FELUWA is a hermetically sealed, hydraulically activated, compact, economical MULTISAFE® double hose-diaphragm pump with in-built compressor and bypass flow control for pressure ranges up to 16 bar. A pump technology that till now was only available for the continuous operation with expensive process pumps (> 8000 h MTBR and high energy efficiency).

Conveyance of aggressive and abrasive media in the low pressure range

Up to now, only a limited selection of energy and wear-intensive pump technologies was available for the conveyance of abrasive slurries in process engineering industry or for aggressive fluids in chemical industry for low pressure ranges below 16 bar. The EcoTrans MULTISAFE pump design is regarded as real alternative to traditional air-operated diaphragm pumps and rotating displacement pumping systems.

The solution
The demand of the process engineering industry for an energy-efficient, low-maintenance technology saving operating costs was answered through the development of the EcoTrans MULTISAFE®. It provides an economical pump technology for low pressure ranges which till now was only available for large process pumps.

Fig 2: The in-built piston compressor provides optimum filling of the pressure air vessel and thus ensures negligibly low pulsation.
Picture: FELUWA

The EcoTrans MULTISAFE® product range (see Fig. 1) represents the latest generation of hydraulically-activated double hose-diaphragm pumps. This type of pump is particularly utilized for critical applications, mechanically abrasive and chemically aggressive liquids as well as highly viscous media (even with particles) of different consistencies. Depending on the respective medium, the dry-matter content can be up to 80 %.

The pumps operate as a stand-alone system. The in-built piston compressor for feeding of the pulsation dampener omits the need for any external media supply in the form of compressed air, water, etc., except the power supply for the electric drive (Fig. 2).

The high energetic and volumetric efficiency as well as the long service life of the hose-diaphragms reduce the operating and maintenance costs to a minimum. The hose-diaphragms, which are usually not considered a wear part when compared to conventional flat diaphragms, are designed for a service life of more than 20,000 operating hours. If utilized correctly, the costs for spare parts only amount to 2 % of the acquisition costs (CAPEX) per year.

In several field tests under real production conditions the pumps have already demonstrated their reliability for the handling of abrasive fluids.

Functionality and mode of action

The EcoTrans MULTISAFE® pump's mode of action is essentially based on an oscillating piston, which periodically increases or decreases the respective inner pump or working space of the outward hermetically sealed hose-diaphragm by means of hydraulic fluid (oil or water hydraulics). The suction and discharge lines are thereby alternately connected to the inlet and outlet valves. The displacement mechanism performs a simultaneous suction and discharge stroke per operating side with each stroke. During the suction stroke, a respective amount of liquid will pass through the suction pipe into the pump working chamber through the opened suction valve. During the discharge stroke, the conveyed liquid is displaced into the discharge pipe through the now open valve, while the suction valve seals the suction side.

Special features

The EcoTrans pump is safe against dry running condition, equipped with a pressure relief valve in the hydraulic system and Industry 4.0 compatible. The cylindrical shape of the diaphragm facilitates the favorable flow behavior, guarantees material-friendly conveyance and is also perfectly suitable for pumping of heterogeneous fluids with solid particles, without any actual wear.
For the handling of chemically aggressive fluids a broad range of hose-diaphragm materials is available. They thus guarantee the process-secure chemical resistance for almost all conveyed media.  

Taking advantage of the gravity effect

Customized pump systems are available depending on the influence of the particle density, sedimentation or buoyancy speed: traditional pumping from the bottom to the top for fluids with  buoyancy speed and DFT (DownFlow Technology) for media which tend to settle and cause blockages.
With DFT, the traditional pumping principle is literally turned upside down, which means flow from the top to the bottom of the pump using the effect of gravity. Thus, sedimentation within the pump is reliably avoided. The consistent modular system allows for individual on-site adaption.
Additional solutions which ensure SIP and CIP cleaning processes to enable “puddle-free” draining are available.

In-built piston compressor

Open pulsation dampeners (so-called air vessels) are utilized to reduce the pressure and flow fluctuations resulting from the oscillating operating behavior and to equalize the subsequently developing pressure spikes.
The in-built compressor is used to solve the problems which are associated with the gas filling of the air vessel being drained with each stroke due to the gas-solubility of the conveyed material. The described double hose-diaphragm pump in modular version was designed in such a manner that the piston rod, which is guided on two sides, can optionally also be used as in-built compressor. The in-built piston compressor reliably ensures that during each return stroke of the piston rod a small amount of filtered air (or gas) is sucked through a valve into the compressor chamber. During the forward stroke of the piston rod, this amount of air is fed into the air vessel via a non-return valve. Through this, the existing volume of air in the air vessel is always perfectly supplemented, and the residual pulsation is reduced to a minimum (see Fig 3.).
The attained dampening does not only facilitate a significantly smoother conveyance, but also a greater degree of efficiency, because the pressure fluctuations are very low. The in-built compressor also enables the utilization of low-cost single-acting pumps with low "peak to peak" pressure pulsation, where till now only expensive double or triple-acting pumps could be used.

Fig. 3: Pressure gradient with 15 bar (simplex pump, flow rate 2.5 m³/h, air vessel capacity 10 liters).
Picture: FELUWA

Internal flow rate regulation

The EcoTrans MULTISAFE® employs the same flow rate regulator as the high pressure pumps. It utilizes hydrodynamic principles to reliably regulate the position of the double hose-diaphragm as well as the highly efficient internal flow rate reduction in case of filter press feeding and similar applications, without the need for a costly and ineffective bypass regulation.

Conclusion:

The expansion of the existing range of pumps created with the EcoTrans MULTISAFE® meets the current and anticipated future demands of plant operators, who are continuously striving to create a competitive advantage. With the constant pressure to implement efficient, low-maintenance as well as effective systems, this pump type will offer an opportunity to reliably fulfill these requirements.

FELUWA offers cost-efficient and process-safe pumps for corrosive and toxic media

The selection of suitable pumping technology, as well as the energy-efficient use of raw materials, is especially challenging if the manufacturing plant operator handles corrosive or toxic media. When designing a pump specifically for the production of polyaluminium chloride, special materials were used to avoid any pump corrosion by the aggressive medium. Furthermore, the double hose-diaphragm pump meets the optimum technical requirements for this challenging process and ensures low-pulsation operation, while simultaneously providing favorable procurement and operating costs.

At the end of the process chain in many industrial manufacturing processes, a by-product is created in addition to the desired commodity. This by-product often has a commercial use. An example of this comes from an Indian production unit for caustic soda. When producing caustic soda from sodium chloride, large amounts of chloride slurry are created, an acidic and therefore particularly aggressive medium. Over the course of the process, the chloride is made to react with aluminium hydroxide in order to produce polyaluminium chloride (PAC), which is an extremely corrosive solution with a pH value of between 1 and 3. A suitable high pressure pump feeds the PAC at high temperature and a pressure of 70 to 100 bar into a spray dryer, where PAC powder in micro-fine parts is produced as an intermediate product for further use. PAC is used in water treatment and also in the cosmetic industry for making antiperspirants (deodorants).

The PAC production process presents several challenges which must be considered when selecting the suitable pump. The criteria include:

-    pressure and corrosion-resistant materials
-    hermetically sealed process
-    pressure of 70 to 100 bar
-    temperature up to 120 °C
-    low pulsation
-    optimum efficiency
-    minimum costs (capex and opex)

Titanium as material

The high pressure has to be maintained in order to achieve even granulation of the PAC powder. With pressures of up to 100 bar, metals are primarily considered as the material for piping and valves. Both Hastelloy C and titanium resist corrosion. Based on specific experiences and tests, the operator decided to have medium-wetted and pressurized parts made of titanium, whereas PTFE (polytetrafluoroethylene) was to be used for seals and to separate the wet end from the drive end.

Due to their special design, displacement pumps have proven themselves for such demanding processes at high temperatures. Screw spindle pumps and eccentric screw pumps do have low-pulsation properties, however the special requirements, such as hermetic seals and material resistances, are difficult to align with reasonable overall costs. Centrifugal pumps are not applicable because of the high operating pressure.

Undesirable pulsations

Taking the process-related requirements into account, only a plunger or piston pump can be used. In this case, the decision was made in favor of a double hose-diaphragm pump. Spray dryers are generally very sensitive to pulsations, but a triple acting pump with offset arrangement of the crank shaft/connecting rod assembly by 120° has proven successful in ensuring operation at low pulsation. Through use of an appropriately sized pulsation dampener, the residual pulsation can be reduced to less than 1.5%. Furthermore, the use of a triplex pump ensures that low pulsation is even maintained at the very low maximum flow rate of 2m³/h required for this specific spray dryer.


Fig. 1: Schematic diagram of a triplex pump with integrated pulsation dampener

Reduce slurry-wetted parts

The slurry-wetted parts of the feed line and connecting pipe, as well as the check valves and valve seats, are made of titanium. While the inner parts of traditional diaphragm piston pumps, e.g. diaphragm casing and pump cover, are in direct contact with the pumped fluid, the slurry chamber of the chosen double hose-diaphragm pump is sealed from the environment by double seals. Fabricating the pump heads from titanium was therefore not required, which contributed significantly to cost reduction.

By using a flexible double hose-diaphragm, the medium is fed through the pump in a favorable way without contact to any parts subject to pressure. The pressure within the pump casing and pump head caused by the displacement of the plungers is the same in the hydraulic fluid and in the medium, which means that the only function of the diaphragm is to separate the critical medium from the hydraulic fluid. Almost identical pressure is maintained inside and outside the diaphragm, so that the diaphragm is only subject to deformation energy and no other stress. This design helps noticeably reduce costs for maintenance and wearing parts.

Fig. 2: Traditional diaphragm piston pump (left) & double hose-diaphragm pump with hermetical sealing of the conveyed fluid and sensors (right)

Material with special properties

While the hose-diaphragm for many standard applications is typically made from NBR (nitrile rubber), this particular case of PAC application only allowed for PTFE as the diaphragm material. With this special material, which is resistant to the corrosive properties of PAC, a service life of more than two years is achieved. Valve balls and valve seats are therefore regarded as the sole real wearing parts of the chosen pump design.

Safe operation thanks to proven technology

In addition to the special features, proven serial parts offer the ideal solution regarding initial and operating costs. Additional features guarantee safe and low-wear operation. When exchanging wearing parts, in this case only the internal parts of the check valves, the pump remains integrated in the piping. Specially developed sound sensors allow condition monitoring of every individual valve. Thanks to these sensors, only the actually affected valve is subject to maintenance, which in turn reduces the operating costs.

The pump is usually driven by a variable speed motor. If two or more units are being operated in parallel, electronic crankshaft coupling is applied, which further reduces pulsation in the system, resulting in a uniform volume flow. By means of crank shaft coupling, an appropriate offsetting of the crank angle is maintained over the whole duration of the operating time, which means that two triplex pumps are working at the uniformity of a six-head pump.

Thus the used double hose-diaphragm pump combines the operator’s special requirements with the proven and tested properties of a serial product.

Fig. 3: Double hose-diaphragm pump for polyaluminium chloride production

Source & Pictures: Mr. Gänsel / FELUWA

Safe and resource-saving pipeline transport of fluids up to 300 km with just one pump station

By means of hydrotransportation, solids in a carrier fluid, which is mainly water, can be transported through a pipeline over distances of up to 300 km. FELUWA MULTISAFE® double- hose diaphragm pumps enable the efficient and reliable pipeline transport of solid-liquid mixtures with only one pump station. These hermetically sealed positive displacement pumps not only achieve a significantly higher level of cost-effectiveness than traditional transports by road or railroad, the process is also environmentally friendlier and conserves natural resources.

FELUWA MULTISAFE® double hose-diaphragm pumps are unique piston diaphragm pumps which have been used in hydrotransport for decades. The double hose-diaphragm ensures separation of the wetted parts from the drive end and guarantees reliable and low-wear transport of abrasive, aggressive and challenging media. Furthermore, piston diaphragm pumps offer a cost-efficient, reliable and particularly low-emission alternative whenever traditional means of transport fail in locations that are difficult to access.

Field-tested FELUWA MULTISAFE® double hose-diaphragm pumps

FELUWA Pumpen GmbH delivered three MULTISAFE® pumps type TGK 500 - 3 DS 350 to a copper producer in Russia. They will be used in a mine for the disposal of thickened tailings. Important ecological aspect: By pumping thickened mine waste, considerable amounts of water and energy can be saved.

In the case of the Russian copper mine the goal was to extend the operating life of the existing reservoir. This resulted in the necessity to reduce the water content in the tailings. The increase in the solids content from 17 to 70 percent leads to a heightened discharge pressure of 80 bar, which is still in the lower range for FELUWA pumps, since they are able to handle pressures up to 350 bar.

Another advantage of this approach is that the thickened mine waste could be pumped into the old open-cast mine and be recultivated afterwards. Building a new reservoir became redundant.

In summary, the high solids content in the medium saves up to 44 million m³ of water per year. Useful for comparison: The football stadium “Allianz Arena” in Munich, Germany, corresponds to a volume of approx. 3 million m³ and could be filled with this amount of water more than 14 times a year. The FELUWA MULTISAFE® double hose-diaphragm pumps thus contribute to considerable savings in natural resources at maximum process reliability.

Quintuplex design of MULTISAFE® double hose-diaphragm pumps

The pumps the success story of success of the FELUWA MULTISAFE® pumps. Among other things, FELUWA is proud to have delivered the world's largest piston diaphragm pumps. Three 5-head Quintuplex double hose-diaphragm pumps have been successfully utilised for years in a copper mine in Mexico to reliably transport an extremely aggressive mixture of seawater and solids.

Source & Pictures: FELUWA Pumpen GmbH

The pump according to EHEDG guide lines ensures purity, cleanliness and hygiene for food production

Purity, cleanliness and hygiene rank first when it comes to food production. Nowadays, hygienic design is more important than ever to avoid microbiological contamination or foreign objects/particles in food. But the food market is subject to constant changes and fast-moving. Consumers prefer fresh produce which should be easy to prepare or require little or no heat treatment. In addition, the demand for products with less sugar, salt and preservatives has increased. There is an enhanced risk of a growing number of microorganisms in food enforced by these developments. This results in increasing requirements for machines in hygienic systems, such as pumps that come into direct contact with the product in food production.

FELUWA MULTISAFE® double hose-diaphragm pump in hygienic design

FELUWA MULTISAFE® pump in hygienic design

FELUWA recently delivered a pump in hygienic design to convey glucose solution in accordance with the EHEDG design guidelines. The TGK 300 – 3 DS 100 achieves an operating pressure of 105 bar and a flow rate of 60 m³/h.

Contamination of the pumped medium, in this case the glucose solution, would result in high costs. The product would be unusable and the worst-case scenario would be a loss of trust among customers and the closure of the plant. FELUWA MULTISAFE® pumps in hygienic design are suitable for the abrasion-free and gentle transport of food with maximum cleanability. Hence our pumps ensure safe operation in food production with reliably good quality and thus increase product safety.

Another advantage of the FELUWA MULTISAFE® pumps is the hygienic component design, as they are safe and clean due to the hermetically sealed separation of product and drive end. A pair of redundant hose-diaphragms, which are arranged one inside the other, guarantee double hermetic sealing from the drive end. The conveyed fluid will neither come in contact with the pump head nor with the hydraulic area. In the past, other manufacturers used plunger pumps to pump glucose. With this design, however, the plunger is in contact with the medium, glucose and lubricants mix and the fluid is contaminated.

The small number of medium-wetted parts and the ideally shaped pump head in terms of flow technology are characteristic advantages of the MULTISAFE® double hose diaphragm pumps. They guarantee optimum cleaning options and gentle transport.

Cleanability is crucial

In order to meet the requirements of hygienic design, all components and pipes in contact with the medium must be (self-) draining and easy to clean. Horizontal surfaces have to be avoided – they should always be designed to be slanting to one side, so that liquids can drain freely without leaving residual fluid.

In addition, the selection of fluid-contacted materials is important to ensure optimum cleanability and thus the highest level of cleanliness and biological safety. The wetted parts of the pump conveying glucose solution are made of 1.4404 with an electropolished surface. Furthermore, NBR hose-diaphragms with FDA certification are used.

The use of DownFlow valves with floating balls allows for optimum cleaning / CiP flushing without dismantling the components or manual cleaning. Additional setup and work steps are redundant, the pump can easily run completely dry by opening the flushing connection. In the process the ball drops and opens the gap between the ball and the valve seat, so that the medium behind it can also drain off. Diaphragm pumps with conventional check valves require special lifting devices to lift the valve body for emptying the pump – these can be omitted in FELUWA’s design. The hygienically designed pumps of the MULTISAFE® series also allow sterilisation with superheated steam.

EHEDG-conformity

In all areas of food and beverage, MULTISAFE® double hose-diaphragm process pumps ensure safe food production in accordance with EHEDG guidelines.

Pump head in hygienic design

Source & Pictures: FELUWA Pumpen GmbH