Oktober 2004
High viscosity liquid pumps for barrels and containers
If it can flow, we can pump it

The preparation of food, chemical, pharmaceutical and cosmetic products inevitably involves the handling of fluids originally stored in drums, tanks or other containers for use in the different steps of manufacturing processes. For such liquid handling, barrel pumps with high speed motors working according to centrifugal pump design are particularly suited. Barrel pumps can still handle small quantities of medium viscosity products up to approx. 1000 or 1200 mPas. But for handling larger quantities, already at a viscosity of 500 mPas, high motor speeds may prevent the fluid flowing quickly to the pump inlet, resulting in an unsatisfactory pump output. This is where special high viscosity liquid pumps, operating at speeds of max. 1000 rpm, come into their own. These pumps are especially designed for handling high viscosity substances such as pasta dough, sugar syrups, honey, polymer solutions, various oils and greases, paints and lacquers, pastes and creams, as well as abrasive materials with solid particles or even sticky substances. High viscosity liquid pumps are of an eccentric worm pump design and will allow transfer of substances with viscosities of up to 100,000 mPas or, in extreme cases, up to 250,000 mPas. The output rate depends on the pump speed and the nature and structure of the product being transferred.

Viscosity, structure and density are the deciding factors

Certain criteria must be considered when selecting a high viscosity liquid pump. First and foremost is the product to be handled. Most decisive are the viscosity, structure and density. Free flowing liquids will not present any problem. However in handling sticky substance, such as long-chain silicon oils, high pressure losses are encountered. The pump speed and output rate then will have to be adjusted to such conditions. The user should also be aware how the product will behave on changes in temperature or pressure. Many lacquers, for instance, become thinner when under pressure; other media become more viscous as a result of the movement induced by pumping. Only an on-site test can provide the certainty that the right pump has been selected. This applies particularly to "non-Newtonian" liquids whose exact viscosity cannot be determined but who will change significantly when it is moved. There are also other substances which harden as a result of reactions with other materials or the air. In such cases precautions must be taken to ensure that the high viscosity liqud pump always operates in an atmosphere in which the medium cannot harden and that the pump is always cleaned immediately after use.

The correct choice is always important.

The immediate environment in which the pump is to work is also very important: the space available, portable or stationary use, potentially explosive areas etc.
Compact, robust construction, low weight and, for example, the use of explosion-proof drive motors are necessary. Especially as to explosion-proof requirements, it is often overlooked that even if non-flammable liquids will be transferred, the cleaning agents with which the pump will be flushed require an approval for use in hazardous locations Zone 0; in other words, the pumps must comply with ATEX-Directive 94/9/EC.

Easy cleaning and handling - vital considerations

Cleaning and hygiene requirements are particularly important in the pharmaceutical and cosmetic industries. The pumps used for these applications must therefore have as few components as possible and have to be dismantled in no time. The pump design should not include "hidden voids". It should have smooth surfaces, eliminating any sharp edges or undercuts where residues and bacteria can built-up. Ease of handling also plays an important role. Compact construction and low weight allow less athletic personnel to move the pump to the next container or to handle the pump during cleaning. Reduced weight can be achieved, for example, by the use of light-weight collector or compressed air motors instead of large three-phase motors.

The optimum high viscosity liquid pump using modular principles

FLUX-GERÄTE GMBH in Maulbronn has designed their high viscosity liquid pumps according to the modular principle. This allows to offer a pump meeting the exact requirements of every specific application. FLUX high viscosity liquid pumps are of a very compact design and operate with minimal wear. The pumps are made in stainless steel, a selection of stator and sealing parts is available to suit the liquid being pumped. Collector, compressed air or three-phase motors as well as explosion-proof models (according to ATEX-Directive 94/9/EC) are available. The pumps comply with Category 1; they are tested and approved for use in Zone 0. The pumps can be used vertically or horizontally. Two sizes with tube diameters of 50 or 54 mm are suitable for use with every drum. The immersion lengths are between 400 and 2000 mm. Eccentric worm-drive pumps can be manufactured with lengths of up to 4000 mm for special applications. Low pump weight enables them to be easily handled in either portable or stationary use. The importance of cleaning was also considered in the pump design. The outer tube can be quickly and easily released from its fixings and removed for cleaning and/or sterilisation. There are no hidden and inaccessible voids where bacteria can lodge. All pump components which come into contact with the medium are easily accessible. A special 3A pump model meets even the most stringent hygiene requirements.

And if it won't flow...

FLUX has developed the VISCOFLUX system for emptying drums of substances which will not flow naturally, for example Vaseline, gels or fats from fat class 2.5 to 3. This system is capable of moving sluggish substances from 200 l drums and consists of an eccentric screw pump with a follower plate which is fixed in a guide cylinder and which can be easily mounted on a metal drum. The flexible sealing lip fixed to the follower plate covers the drum contents and is automatically pulled downwards by the vacuum which occurs when the drum's contents are removed. This ensures that the medium is pushed uniformly downwards with the result that the medium is removed without interruption and that nothing remains on the sides of the drum. Once the drum is empty, a control unit simply opens a valve to ventilate the drum, after which the pump is returned to its starting position by the action of two compressed air cylinders.

Accessories

A wide range of accessories can also be supplied to ensure perfect fluid handling and control - liquid meters made from a variety of materials, hoses suitable for the different media, handy pump nozzles and overflow valves - the latter are especially important for use with eccentric screw pumps. Thanks to the company has developed all major components and even the drives, it is relatively simple for FLUX to produce equipment for unusual customer require-ments. And, the company also focusses on quality. With their quality control management system FLUX-GERÄTE GMBH strictly aim to a global market - certified according to DIN EN ISO 9001, FLUX high viscosity liquid pumps are manufactured according to 3A standards and also meet the American FDA standards.

For further information:
FLUX-GERÄTE GMBH, Talweg 12, D-75433 Maulbronn
Phone: 0 70 43 / 101 - 0, Fax.: 0 70 43 / 101 - 111
Email: info@flux-pumpen.de