Knoll Maschinenbau GmbG

Archive for: 2010

Cleaning Pumps Inside and Outside

Pumps need to be cleaned easily. But in most cases attention is paid only  to the interior of the pump while the pump housing and the drive get much less attention. In the American Food Industry there is an ever increasing demand on general hygiene that is being extended to the exterior of the pumps. It is now as important for the exterior of the pump to  be cleaned as easily as the interior.

Because of this requirement, pumps must be cleanable with high pressure cleaners. For instance, pumps cannot have painted parts that would discourage high pressure washing. This requires smooth outer contours without dead spaces, so that no dirt traps or residues of cleaning fluids occur. In addition the atmosphere side surfaces of the pump need to be corrosion resistant to aggressive cleaning agents.

KNOLL Maschinenbau can meet all of these requirements with its MX progressing cavity pump: The MX is designed completely in stainless steel, which also applies to the stator jacket and the drive. There are no covers on the drive. Covers normally accumulate a lot of dirt and are unsuitable for very hygiene-sensitive work environments. As a drive in stainless steel, gear, servo and stepper motors are offered, so that a wide range of use cases can be covered.

In addition, the MX from KNOLL Maschinenbau maintains the highest degree of internal sanitary standards (CIP and SIP) – like in the standard model. As a consequence this progressive cavity pump is ready not only for food industry, but may as well assist in pharmacy, biochemistry and cosmetics in order to meet highest hygiene requirements.

Pumping Abrasive Media Economically: The MX in a Special Design

When it is necessary to transport abrasive media the pump can easily become a problem child: Abrasive fluids can lead to high wear and short lifetimes. A Portuguese paint manufacturer experienced this when he had to promote calcium carbonate. So he gave the MX-Pump from KNOLL Maschinenbau a try.

His demand: To pump 70% calcium carbonate in aqueous solution with a particle size of 6 microns at a pressure of 5 bars and to convey a capacity of 60 m³ / h. KNOLL provided him with a MX50 progressive cavity pump in special design: The stator is lined with a wear resistant elastomer, the rotor coated in special stainless steel (“ductile coated”). The universal joint also receives a sleeve in a wear resistant elastomer. Overall this MX-Pump appears as highly abrasion- and corrosion-resistant and therefor meets the high requirements of the chemical industry, especially when it comes to paints and coatings.

The result: After one year of continuous use of the MX the Portuguese paint manufacturer was completely satisfied. In a three-shift manufacturing process the progressive cavity pump from KNOLL could fully convince: After more than 6.000 hours in use no loss of flow or pressure occured.

But not only the abrasion- and corrosion-resistant construction of the pump contributed to this result but also its design principle with a stator in Even-Wall-technology – a standard in every MX-Pump from KNOLL. This stator is responsible for the fact that practically no back flow of media occurs, which is very welcome especially when abrasive media such as calcium carbonate have to be pumped. As a consequence no blast wear appears.

Another advantage of EvenWall-technology is its significant improvement of the stators characteristic, compared to a pump with conventional stator. This has quite a considerable effect on the cost-effectiveness. The picture shows the characteristic of a conventional stator (left line) and of a stator in EvenWall-technology (right line).

Overall the MX-Pump with its special design convinces not only because of the very high resistance to abrasive media but also on the level of operation efficiency and cost-effectiveness.

Our Diversity of Pump Materials: It’s Your Choice!

A good pump can be adapted to many different transport media and it’s the pump materials that make a decisive contribution to this. Therefor KNOLL Maschinenbau offers a wide range of materials for its progressive cavity pump, even usable in different combinations, so that for nearly any type of transport medium the right pump can be selected.

For its standard design KNOLL applies stainless steel in food quality for all components in contact with product. In addition, however, designs in cast iron are available for applications where stainless steel is not required. In both cases, ie stainless steel or cast iron, of course, all other advantages of the pump stay the same: Ease of servicegood cleaning ability, and of course the benefits of EvenWall-technology.

Why is stainless steel so often used in pumps? It is its high corrosion resistance which distinguishes it from other materials. Depending on the composition of the steel this corrosion resistance can be increased even further.  Hence KNOLL’s MX-Pumps can be fully made of stainless steel or using stainless steel only for all components in contact with product. Progressing cavity pumps fully made of stainless steel are more and more requested from manufacturers with very high hygiene requirements.

Elastomers also play an important role in progressive cavity pumps. For the MX-Pumps more than 100 different types of elastomers (among them many with numerous certificates) are available. This allows an individual adaptation and thereby chemical resistance for each pump to its transport medium. If in your case experience on the resistance of your medium is not available yet, swelling experiments in the KNOLL laboratory are possible at any time.

In particular, we keep in mind the consistent quality of each elastomer used: For every single application the exact same elastomer recipe is used so that the repeatability of the pump parameters remains the same. Especially when the progressive cavity pump is used as a metering pump this is very important: A replacement of the stator must not lead to a re-parameterization of the pump in the manufacturing process. Therefor KNOLL Maschinenbau guarantees for its MX-Pumps and its original spare parts high repeatability.

Finally KNOLL also provides a stator in Teflon for cases in which an elastomer cannot be used. Such solid stators are suitable for aggressive fluids, as often used in the chemical industry, for example in form of paints with solvents.

The Modular Design of KNOLL’s MX-Pump: More Flexibility and Less Costs

Pumps employed in industrial manufacturing processes need to meet high standards. In most cases their capacity and the required back pressure are in the forefront of attention. But since pumps are durable capital goods, it is also worth looking at their modularity, as changing production conditions mostly have impacts on the pumps, too.

This is the reason why progressive cavity pumps from KNOLL Maschinenbau come with a modular design built-in. It is the ideal prerequisite for adaption to changing production conditions. For example in the case of the MX20 nine different sizes can be derived from the basic model, so that the pump can be optimally adjusted to parameters like flow rate or pressure with replacing only few parts. This is achieved through modular rings compensating different diameters of pump assembly versions in the suction housing and pressure joint.

The modular design brings advantages not only for the end user, but also for plant constructors as they can reduce the number of design components significantly, due to the fact that the connection size concerning height is always the same for nine different pump sizes – variations occur only in length.

Even larger suction housings can be adapted quickly and easily without additional components. This makes sense for high-viscosity and lumpy media. Considering the MX from KNOLL Maschinenbau in terms of life cycle costs, the modular design clearly  offers substantial benefits: Its flexibility due to few components makes it easy to change parts and simplify the supply with spare parts. In addition the modular design helps to adopt fast to changing operational scenarios and manufacturing demands.

Thus, the progressive cavity pump MX becomes a worthwhile investment for many areas of application as it can convince not only on the technical but also on the economic level.

KNOLL’s MX-Pumps Meet the 3-A Sanitary Standards

The progressing cavity pumps from KNOLL Maschinenbau correspond now to the 3-A Sanitary Standard (United States of America). In addition to the EHEDG-certification the MX-Pumps now meet another very important standard of hygiene. This underlines once again the suitability of this pump for applications under the most stringent hygiene requirements.

The 3-A Sanitary Standard  goes back to the 3-A Organization founded in 1920, which was a merger of three non-profit organizations. The goal was to establish criteria for the equipment and thus the product quality of dairies. This was intended to protect the health of consumers of dairy products. Since 2002, there is also the 3-A Sanitary Standard Inc. as a subsidiary organization of the 3-A, defining mandatory standards and monitoring any compliance with them. The work of the 3-A organization is widely recognized outside the USA and no longer just used in the production of milk, but, for example in the pharmaceutical field, too.

The certification due to 3-A primarily relies on the structural features, namely the structural design, surface quality and the materials used (for example the elastomers). Even the manufacturers of the seals must comply with this and prove certification of their products. This even extends to the level of staff members involved in the production: They must be certified for certain activities themselves.

This method of certification differs fundamentally from a certification due to EHEDG, where the pump is running a trial subjected to practically similar circumstances as appearing in normal production cycles.

A special feature of the MX-Pump from KNOLL is the fact that it has received certification to 3-A in its standard version, only with very minor modifications, covering the series MX20, MX30 and MX50. For buyers of such pumps this brings a significant price advantage, as in most cases no (expensive) supplementary parts are needed. Moreover, the supply of spare parts can be kept easier and faster because the required high quality already is included in the standard version of the series.

Pumping and Tempering Sensitive Media

Today many manufacturing processes are not possible without the use of pumps. And often not only the role of pure pumping, but also tempering is important, as the transport media must be kept on a very specific temperature level. The pump must therefore be able to temper – which means cooling or heating due to the specific process.

In the case of sensitive goods in transit it must be ensured that they do not get into contact with the tempering media. Any contamination must be ruled out. KNOLL Maschinenbau has therefore  specially designed its MX progressive cavity pumps, so that tempering with steam, water or oil is possible without contamination of the sensitive transport media.

In order to achieve this a double jacket on the suction housing as well as on the pump assembly gets applied. This solution offers several advantages:

  1. High pressure stability: The double jacket keeps up with a pressure of up to 5 bar, for example when the pump gets tempered in the context of an overall tempering of pipes and containers.
  2. Good tempering properties: The stator in EvenWall-design provides a relatively large surface area with even elastomer wall thickness and thus very good characteristics for tempering.
  3. Extremely easy to service: Even when fitted with the double jacket for tempering the MX from KNOLL remains an extremely easy to service pump because all parts are still equally accessible.
  4. Stator-Relining: If there is wear on the stator, it can be reprocessed. For this, the elastomer used is burned out, so that the stator shell can be used for a re-vulcanization. Cost savings and protection of the environment are the consequences.

Finally, it should be mentioned that this progressive cavity pump offers high efficiency and carries only very little heat on its transport medium. Therefore heating will practically not occur, so that a “well-tempered” pumping and transport operation is guaranteed with the MX from KNOLL Maschinenbau.

KNOLL’s MX with EHEDG Approval

For machinery and equipment that are used in the production of food, compliance with EHEDG (European Hygienic Engineering & Design Group) is a mandatory standard which has gained wide application even beyond Europe. This is also true for pumps used in food production.

The basic aim of the EHEDG directive is to prevent the microbial contamination of food. Thus, the microbiological safety and quality of the food is taken into account. The guidelines relate to the structural design, surface finish, the materials used, cleaning ability and the prevention of penetration and the growth of microorganisms in the machinery and equipment.

As we’ve reported here on the blog, the MX-Pump is certified to EHEDG. KNOLL Maschinenbau was awarded the accompanying certificate in June 2010. A remarkable design feature of the pump was noted during the examination by the Research Centre Weihenstephan for Brewing and Food Quality of the Technical University (TU), Munich. It’s the fact that the MX, thanks to its aseptic design, usually is cleaned without an additional CIP-Pump.

Therefore bypasses and valves can be omitted. In most cases these only form unwanted dead spaces, which get traversed only in the cleaning process.

A further  hygienic advantage is the self-cleaning effect oft the MX-Pump: For emptying the pump its suction casing is fitted with a special suction nozzle that is welded horizontally and tangentially, so that the effect of self-draining occurs on the suction housing as well as on the progressive pressure joint.

The Benefits of Progressive Cavity Pumps Compared to Other Pumping Systems

When a new manufacturing plant gets planned or an existing plant needs to be modernized, often the question of the right pumping system is taken into consideration: What type of pump is the correct one? The following list speaks in favor of the progressive (progressing) cavity pump:

  1. Gentle conveying of the medium: the pumping chambers in the pump assembly remain constant, so that the product gets neither crushed nor sheared. The non metal to metal contact of the progressive cavity principle is far superior when pumping abrasive particles in suspension.
  2. Different viscosities are equally well served: From low to high viscosity media the progressive cavity pump handles everything, even thixotropic or entrained air fluids. This makes it extremely flexible and versatile in its range of applications.
  3. No backflow into the pump: When stopped the progressive cavity pump closes like a slider (valveless pump) so that practically no backflow returns to the pump.
  4. Very good suction performance: With its excellent suction performance this pump is the right choice for emptying barrels, mixers and containers of all kinds (big bags). Progressing cavity pumps from KNOLL Maschinenbau offer a negative pressure of up to 0.2 bar absolute, when fitted as suction, submergible and following plate version.
  5. Metering accuracy: Due to low pulsation the progressive cavity pump offers very exact metering. An additional valve is not required.
  6. Linear characteristic curve: Since there is no backflow into the pump, the flow rate is increasing always proportional to the speed. Thus, the optimal efficiency of this pump extends over a very wide range.
  7. Suitable for high pressures: Progressing cavity pumps from KNOLL achieve a pressure increase of up to 80 bars, which makes them an interesting proposition for sophisticated engineering. The higher pressures are desirable for moving product greater distances and for applications involving extrusions.

The MX-Pumps from KNOLL therefore are used in a wide range of  different applications. Here is a selection of media that will be optimally promoted by this progressive cavity pump:

  • In the food and beverage industry: dairy products, raw and cooked vegetables, fruit mash, concentrates (eg juices), liquid egg dough, color and flavor, butter, cooked dishes, raw and auxiliary materials and finished materials for the confectionery industry, chocolate (with and without lumpiness), animal food;
  • In chemistry, biochemistry, pharmaceuticals and cosmetics: paints and coatings, resins, waxes, adhesives, raw and auxiliary materials for the pharmaceutical industry, peels, cosmetic products (including products for organic and natural cosmetics).

Why KNOLL Uses Universal Joints for the MX-Pump

Progressing cavity pumps are unmatched in their ability to transport viscous, abrasive and shear sensitive fluids. One of their important components is the joint, responsible for power transmission from the drive shaft to the rotor. Technically seen different solutions are possible here, for example the pin joint or a flexible rod.

KNOLL Maschinenbau has decided to use universal joints for the MX-Pump. These joints are characterized by robustness which is important in metering: An intermitting service for exact metering applies heavy loadings on the joint. Therefor KNOLL relies on the same quality standards as used in the autmotive industry for its universal joints. As a consequence the robustness of the joint is not only helpful in metering but also in transporting highly viscous media or working under high pressure.

But robustness is not the only important factor for the joint of a progressing cavity pump: As much as the joint should be robust as much it has to support the flow of any given media. The MX-Pump from KNOLL offers the same flow rate over the entire length of the suction housing due to the fact that the universal joint has the same diameter from front to end.

A third factor is hygiene: A pumps joint must support sanitary matters under many different circumstances. Depending on the media very high hygiene requirements have to be met. The universal joint of the MX is therefore provided with a specific hygiene sleeve so that no direct contact between transport media and the joint itself is possible. In addition the joint is life time lubricated. The lubrication with vegetable fat is designed for the life time of each MX-Pump. On the exterior, towards the transport media, the hygiene sleeve supports fast and easy cleaning with its dead end free construction. The photos in this article show the universal joint of the MX-Pump without (top) and with (bottom) sleeve.

By using a universal joint in KNOLL’s progressing cavity pump the joint itself no longer counts among the wear parts. In any case of failure very short downtimes are guaranteed, as the MX can quickly and easily be disassembled and reassembled. Therefore the MX from KNOLL Maschinenbau without doubt is a good choice not only due to its technical factors but also following the idea of total cost of ownership (TCO).

Preserving Food Carefully: The Role of Pumps in Pasteurization

What would have Louis Pasteur thought if he could have seen what his discovery has triggered until today? The pasteurization of food of various kinds (not only dairy products) has become indispensable to many parts of the food industry.

Of course this depends not only on the pasteurization (as a process) itself but also on pumps which supply the ready-prepared food to the pasteurization. Often high pressures are necessary for pumping, because pasteurization facilities may have long pipelines. Traditionally piston pumps are used for this. But piston pumps come along with the disadvantage of relatively strong pulsation, which may be detrimental to the following pasteurization process steps.

Here the MX-Pump from KNOLL may be an alternative: This progressing cavity pump can easily build up large pressures as well as carry its transport medium with very low pulsation. Such an evenly generated flow is advantageous especially when transportation of the medium is followed directly by a dosing unit.

KNOLL recently delivered its MX-pump as part of a plant for the pasteurization of sauces. Tetra Pak Processing found itself confronted with the requirement to conduct a highly viscous and shear sensitive medium through the pasteurization facility. A very gentle transport of the medium was a high level priority order of the food manufacturer, so that finally the quality of the pump became the decisive point of the contract. TetraPak finally got the order thanks to KNOLL’s progressing cavity pump.

This example demonstrates the power of the MX-Pump. A pressure of up to 45 bar is no problem. The careful handling of goods in transit finally is a result of the stator built in EvenWall-technology: The constant elastomer wall thickness guarantees a continuos delivery flow, pressure stability and helps to minimize reflux.

The advantages of the MX progressing cavity pump as described here in relation to the pasteurization of food (especially sensitive sauces) are of course equally when applied to the range of beverages or animal food. Different viscosities and media containing solid matter are possible, too.

In sum it can be stated that with the MX from KNOLL Maschinenbau the spectrum of options for pasteurization getrs enlarged. This gives more flexibility and helps to focus on product development for food manufacturers.