The multi-talent: From aqueous to highly viscous and abrasive up to gas-laden CHEMSPIN pumps solve a wide range of problems. They are very flexible, and have a low cavitation risk.
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The 3-A certificate is issued by the American corporation 3-A Sanitary Standards, Inc. (3-A SSI). It evaluates the design of pumps and other equipment using the criteria of Hygienic Design. 3-A is the most important certificate for the food industry in the United States. HYGHSPIN twin-screw pumps are 3-A certified. An EHEDG certification is also available. In addition, the pumps can be designed in accordance with the ATEX directives.
3-in-1 describes a technology in which infeed, conveying, and cleaning are carried out in a single unit, more on this under HYGHSPIN Hopper. This technology is used for products with a high viscosity.
Abrasive media are substances with a grinding, abrasive effect, such as crystals or fruit kernels. They place particularly high demands on the pump. In some cases, abrasive constituents are very small and difficult to detect or feel. An example of the presence of microparticles of this kind is toothpaste. Wear resistance can be significantly increased by diffusion hardening of parts that come into contact with the media.
This abbreviation of the French term ATmosphères EXplosibles refers to a directive on explosion protection. In the European Union, only equipment, components and protective systems designed in accordance with ATEX may be used in potentially explosive atmospheres. If required, all HYGHSPIN twin-screw pumps can be manufactured in accordance with ATEX.
With axial pumping, the medium is pushed through the pump in the longitudinal direction. In a HYGHSPIN twin-screw pump, this is done without contact by two counter-rotating spindles. Because the medium is not centrifuged in this process, as is the case with other positive displacement pump types, axial pumping is particularly gentle on the product and is suitable for example for pumping delicate pieces of fruit. At the same time, contactless axial pumping protects against material abrasion, preventing both penetration of abraded material into the product (contamination) and premature wear of the feed screws.
A bypass is an additional auxiliary line around the pump. In most cases, this line is used to return a partial flow from the suction side to the pressure side of the pump in order to control volumes or pressures. In hygienic applications, positive displacement pumps are often fitted with a bypass to allow cleaning flows to bypass the pumps because the volume flow range is limited. These bypasses are not required for HYGHSPIN twin-screw pumps. With their extremely large operating range, cleaning flows from CIP or SIP process can be run completely through the pump.
Closed design of a mechanical seal; all elements are integrated in a single component. A cartridge design simplifies assembly and excludes the possibility of assembly errors.
With cast components, the shape of the component is achieved largely by casting the material from the liquid phase. The components are then finished mechanically. With casting, there is a risk that small air bubbles – cavities – will be trapped in the material. During subsequent processing of the surfaces, these bubbles may then be opened during the grinding and polishing process to form tiny cavities in which residues of the medium accumulate. These impurities are very difficult to detect and remove, which means that they can easily lead to contamination of the product, which can be associated with health hazards, particularly in the food and pharmaceutical industries. In HYGHSPIN twin-screw pumps, all components that come into contact with the medium are machined from solid stainless steel. Chip by chip, the material is removed from a stainless steel block until the required shape is achieved. Although this process is more complex, it does also offer a higher level of hygiene.
The term cavitation refers to the formation and subsequent sudden disintegration of vapour bubbles. The phenomenon is typically seen in pumps, ship propellers or water turbines. The vapour bubbles form when the local static pressure falls below the evaporation pressure of the medium. This can occur at a temperature as low as around 20 °C. The action of the pump causes the vapour bubbles to return to areas with higher pressure, where they suddenly burst. This creates turbulence, so-called microjets, leading to damage and premature wear of the pump. The crucial factors in avoiding cavitation in pumps are careful determination of the required NPSH values and a system layout that takes account of them.
Cavities are hollow spaces that can occur when metals are cast. The machining of components manufactured by casting can produce microfine cracks in which impurities can accumulate, leading to contamination of the product. To avoid this, the parts of all HYGHSPIN twin-screw pumps that come into contact with the medium are machined from solid stainless steel. This more complex manufacturing process offers the highest level of hygiene.
CHEMSPIN is the brand name for industrial twin-screw pumps made by northern German manufacturer Jung Process Systems GmbH. The CHEMSPIN series includes a range of models in various designs and is usedfor applications in the chemical sector and general industry. CHEMSPIN pumps are very flexible and cover a wide range of viscosities and volume flow rates. They are self-priming and are characterised by low NPSH values. Their combination of properties of different pump principles make CHEMSPIN pumps a real all-rounder.
CIP = clean-in-place – cleaning of the system without disassembly and manual cleaning of components. All HYGHSPIN twin-screw pumps are suitable for CIP processes. Because they have a high operating range, a bypass is usually not required.
Circumferantial piston pumps make up part of the group of positive displacement pumps. They essentially consist of a housing and two counter-rotating pistons. The rotation of the pistons conveys the medium into a pump chamber, and from there into the piping.
Contact-free means that adjacent components do not come into contact with each other. In HYGHSPIN twin-screw pumps, there is no contact between the spindles or between the spindles and the pump housing.
Contamination refers to the contamination of a product, for example with microorganisms or residues of media that have previously been conveyed in the pump. However, contamination can also be caused by the continuous abrasion of a component.
Corrosion refers to the decomposition of a material as a result of external influences. To prevent corrosion of metals by oxidation, corrosion-resistant stainless steels are used for hygienic pumps.
Couplings are used to connect rotating shafts, for example to transmit power at the interface between pump and motor. There is a wide range of different couplings available. With magnetic coupling, even contactless transmission is possible. Most couplings require correct alignment. Otherwise, there is a risk of damage to the coupling or to the bearings for the connected shafts. To rule out the possibility of misaligned or warped couplings, HYGHSPIN twin-screw pumps are offered in a modular design. The spindles and motor shaft are centred on each other by positive locking. This increases operational reliability. At the same time, the coupling is protected against corrosion and the pumps are easier to clean from the outside.
Delivery head is a term used primarily for centrifugal pumps. The head indicates how far a particular medium can be pumped, taking into account various factors such as the density of the pumped medium, usable mechanical work and local acceleration of gravity.
Design free of dead spaces are free of spaces where dirt can accumulate, as this would lead to contamination of the product. Design free of dead spaces is an essential criterion for hygienic design.
In diffusion hardening, additional elements are introduced (“diffused”) into the stainless steel surface as part of a process, often a mechanical-thermal process. This leads to tensioning of the microstructure in this zone, so that the surface becomes harder and more wear-resistant. Details of the process vary from manufacturer to manufacturer.
Double Flow refers to the product family of double-flow HYGHSPIN twin-screw pumps for special high-pressure applications. The models in this series have two external inlet connections and a central outlet connection. Thanks to a special design, the high pressure differences that occur in these models are offset internally, which means that the HYGHSPIN Double Flow range offers high reliability and an excellent service life. In addition, these pumps can handle large volume flows.
Our double spindles are at the heart of our HYGHSPIN twin-screw pumps. Thanks to the two stainless steal spindles running against each other without coming into contact, the medium is pushed gently through the pump in the axial direction. It is not centrifuged or subjected to any other mechanical stresses, so that this pump technology is also ideally suited for sensitive products, for example lumpy products.
Double-flow twin-screw pumps have two parallel stages leading to a central outlet connection. They are particularly suitable for high-pressure applications, as the essential components are subjected to little strain despite the high pressure differences.
Dry-run protection for pumps is in place when the pump can be operated without a pumped medium (e.g. during priming processes) without causing damage to the pump. With double-acting seal rings or lip seals, HYGHSPIN twin-screw pumps are safe to run dry. The lip seals are self-lubricating, so running the pump dry is not a problem. With a double-acting mechanical seal, flushing is used to prevent the sliding surfaces from running dry.
The efficiency of a pump indicates the ratio between the pump capacity and the mechanical power requirement of the pump, i.e. the energy consumed. It is expressed in percentage points. The efficiency can never reach 100% because there is no such thing as a machine that operates without loss.
EHEDG is the abbreviation for the European Hygienic Engineering & Design Group. Like the American corporation 3-A Sanitary Standards, the aim of this organisation is to improve food safety. More than 400 experts from the food industry and the mechanical engineering and research sectors develop guidelines and provide practical instructions for their implementation in terms of hygienic design. Via selected testing institutions, the EHEDG issues certificates for tested components that fulfil the relevant requirements. HYGHSPIN twin-screw pumps are EHEDG certified. A 3-A certificate is also available. Versions based on the ATEX directive are also possible.
Elastomers are dimensionally stable, elastic plastics that are used for example for seals. The elastomers that come into contact with the product in HYGHSPIN twin-screw pumps are usually made of HNBR elastomers (HNBR = hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene diene rubber) or FPM / FKM (fluororubber) and are designed as easy-to-clean FDA-compliant moulded rings.
Extrusion is a moulding process in which a viscous medium is pressed through an opening under pressure. In the HYGHSPIN twin-screw pumps in the Hopper series, the term extruder function refers to the feeding of non-flowable products by means of extended feed screws.
“FDA stands for the Food and Drug Administration, the US regulatory and supervisory authority for food, drugs and medical devices. For pumps and other machines used in the food or pharmaceutical sector in the USA, there are strict regulations in place to prevent any contamination of foodstuffs with impurities, for example through abrasion during processing. All elastomers that come into contact with the product in the HYGHSPIN twin-screw pumps are therefore FDA-compliant and have certificates to that effect.”
A funnel-shaped opening for feeding non-flowable products in the HYGHSPIN HOPPER. This allows products with viscosities of up to 1,000 Pa·s to be conveyed without any problems. Extended feed screws draw the medium into the pump chamber below the feed hopper (like an extruder).
Flank clearance is the distance between the respective “teeth” of the two feed screws running against each other in a two-spindle twin-screw pump. The distance is defined by the specific design and must be checked during maintenance and replacement, for example of shaft seals.
If the setting for flank clearance is not sufficiently accurate, solid body contact between the feed screws can have a negative impact on the pump’s operating behaviour, leading for example to vibrations, damage or loss of performance.
For the HYGHSPINtwin-screw pump, there is a patented design (EP 2 634 366 A2) available that considerably reduces the amount of maintenance work required by making it much easier to adjust the flank clearance. An inspection opening allows the feed screws to be aligned directly in the system without having to disassemble the motor and gearbox housing.
The flow speed refers to the speed at which a medium is transported through the pump. At low flow speeds, delicate products can be moved very gently, as there are neither mechanical (centrifuge) nor thermal (heating) changes caused by rapidly rotating pistons or screws. To achieve high performance at low flow speeds, the entire system layout must be designed individually to meet the specific requirements.
Gaps are narrow spaces between two components. In the design of pumps for hygienic applications, gaps that are not flushed out must be avoided, as otherwise product deposits can accumulate in them, leading to contamination.
Gap loss is the loss of performance that occurs when some of a medium that has already been pumped flows back through internal gaps in a pump from the pressure side to the suction side, meaning that it has to be pumped again. The processes used in HYGHSPIN twin-screw pumps ensure that gap losses occur only to a very limited extent.
Hastelloy is the brand name of a particularly resistant stainless steel material. Hastelloy is used for example in applications with particularly aggressive chemical substances.
In the area of hygienic food pumps, pressures from approx. 16 bar are considered high-pressure applications. In the HYGHSPIN twin-screw pump family, the Double Flow version is available for high-pressure applications up to 50 bar.
HYGHSPIN is the brand name for hygienic twin-screw pumps made by northern German manufacturer Jung Process Systems GmbH. The HYGHSPIN series includes different models in various designs and is used mainly in the beverage and food industry, the fine chemicals sector and the pharmaceutical industry. All HYGHSPIN models are manufactured using a special production process in which all parts in contact with the medium are machined from solid stainless steal. In addition to a design free of dead spaces, this produces a unique level of hygiene. Another special feature of these models is their modular design, which further simplifies mobile applications. The hallmark of HYGHSPIN twin-screw pumps is a very high viscosity range. They serve as universal pumps and are also suitable for CIP and SIP processes with no additional bypasses.
HYGHSPIN Hopper is the brand name for a twin-screw pump with feed screws extended towards the inlet. With this pump type, infeed, conveying and cleaning are carried out in a single unit thanks to 3-in-1 technology. Products with viscosities of up to 1000 Pa·s can be conveyed without any problems. The extended feed screws in the HYGHSPIN Hopper can draw in non-flowable products below the feed hopper (like an extruder) and feed them to the pump chamber. This ensures particularly gentle conveying. The HYGHSPIN Hopper is available in a modular design or with a free shaft end.
Hygienic design is the design of easy-to-clean parts, components and production systems for the manufacture of foodstuffs in order to avoid contamination. Among other factors, the design, materials used, manufacturing processes and joining techniques are examined and evaluated for this purpose. For pumps, a frequently cited aspect of compliance with hygienic design criteria is a design free of dead spaces, which avoids the inclusion of any spaces that cannot be reached by cleaning agents. The principles of hygienic design form the basis for the certification of equipment awarded by the EHEDG on the basis of testing.
The inlet head is the difference in height between the source of the pumped medium and the inlet connection on the pump. The source of the pumped medium is above the pump. If the source is below the pump, the term used is suction head. The inlet head should never be confused with the NPSH value for the system. While the inlet head is included in measurement of the NPSH value on the system side, it is only one of several influencing variables.
With lip seals, the shaft is sealed by one or more lips sliding on the rotating component. They are used for applications with a high sugar content, such as fruit juice concentrates, because standard mechanical seals are less suitable in this area as the sliding surfaces can easily stick together when the pump is idle and may break when it is restarted. HYGHSPIN twin-screw pumps can also be fitted with self-lubricating PTFE (polytetrafluoroethene) lip seals for these applications. An external flushing system is not required, making lip seals particularly advantageous for mobile pumps. The ready-to-install lip seal system is simple in design, safe to run dry and more cost-effective than single-acting and double-acting mechanical seals.
Maintenance is the care, maintenance and servicing of systems, machines and components. The effort required for subsequent maintenance of a product is often determined by its initial design. HYGHSPIN twin-screw pumps are available in a modular design, which is considered particularly easy to maintain.
Mass inertia, also known as mass moment of inertia, indicates the resistance of a component to the change in rotational movement around its own axis. It is an important value because it determines how well the rotating parts, i.e. the pump rotators in the case of pumps, can be accelerated and decelerated. The smaller the mass inertia, the better the parts can be accelerated. The rotors in HYGHSPIN twin-screw pumps have a relatively small diameter compared to the pumping components in other pump designs. This means that their mass inertia is low. These pumps therefore feature excellent acceleration and deceleration.
Mechanical seals are used in a pump to seal the rotating shaft from the pump chamber. A pair of rings essentially consists of a seal ring, a counter ring and a spring. The seal ring is on the rotating part, the counter ring on the static part. Both parts are pressed together by the spring and run against each other. There is a fine film of the respective medium between the seal ring and the counter ring to allow the two parts to move against each other. In the absence of this lubricating film between seal ring and the counter ring, the mechanical seal would run dry and could be damaged as a result. Single-acting mechanical seals, which consist of a pair of rings, are often installed as standard. Double-acting mechanical seals are available for special applications, which consist of two pairs of rings in series. There is a flushing chamber between the pairs. To ensure the formation of a lubricating film on the outer side as well, this flushing chamber must be supplied with a flushing or sealing medium. Double-acting mechanical seals are used with toxic, aggressive or explosive media to prevent direct leakage into the environment. In hygienic applications, double-acting mechanical seals are also used to separate the product from the environment. Media with a high sugar content, such as syrups, require a seal design that prevents the surfaces of the seal ring and counter ring from sticking together when the pump is idle. For applications of this kind, HYGHSPIN twin-screw pumps can alternatively be equipped with low-cost lip seals, which are safe to run dry without flushing.
Microjets are high-energy streams produced by the sudden disintegration of vapour bubbles as a result of pressure differences in liquids. Microjets arise in connection with cavitation. They lead to very high local strain on affected components and very often to damage such as the phenomenon known as pitting.
HYGHSPIN twin-screw pumps are generally offered in a robust, compact modular design. The pump and motor shaft are centred on each other by positive locking. For installations that are less than ideal, for example with mobile pumps, this prevents problems arising from misaligned or warped couplings. In addition, less space is required and the pumps are easier to clean from the outside. Accumulations of dirt under guard plates or a large base plate are prevented. Alternatively, HYGHSPIN twin-screw pumps are also available with a free shaft end.
The moment of inertia indicates the resistance of a body to rotational movement around its own axis. The behaviour of the body depends on how its mass is distributed, or more precisely how far which parts of the mass are from the centre of rotation. The square of this distance is included in the measurement of the moment of inertia. The further the mass from the centre of rotation, the greater the moment of inertia. Because their diameter is small, the moment of inertia of the rotors in HYGHSPIN twin-screw pumps is relatively low. This means that HYGHSPIN twin-screw pumps feature excellent acceleration and deceleration. In addition, high speeds of up to 4,000 min-1 can also be achieved.
The motor shaft is an elongated component that transmits the force generated by the motor – the torque – to a machine part, causing it to rotate. For the connection to the component being driven, a coupling is generally used. The driven machine parts can however also be mounted directly on the motor shaft, so that no coupling is required. This is the case with some pumps and is common with fans.
MTBF is a static value and stands for mean time between failures. It provides information about the average service life (operating hours) to be expected until the failure of a component. The higher the MTBF, the lower the probability of failure of a component. Availability of a component is calculated from the MTBF and the MTTR.
MTTR is a static value and stands for mean time to repair. It provides information about how long on average it takes to repair a component. Knowing the MTTR therefore makes it easier to plan for downtimes. The smaller the MTTR, the faster the component can be repaired. Availability of a component is calculated from the MTTR and the MTBF.
Multiphase pumping is the conveying of a mixture made up of at least two of the three phases (solid, liquid, vapour). HYGHSPIN twin-screw pumps provide an excellent solution to the special requirements of multiphase pumping, because with their wide viscosity range, they can also convey vapours and gases in addition to solids and liquids.
NPSH stands for net positive suction head and is one of the most important operating variables for pumps. The NPSH value indicates how large the pressure difference is between the pressure at the pump inlet and the vapour pressure of the product. Two NPSH values are considered: NPSHR and NPSHP. NPSHR indicates the pressure required by the pump, while NPSHP indicates the pressure provided by the system. The lower a pump’s NPSHR value, the lower the risk of cavitation. The NPSH values should therefore always be request from the pump manufacturer. At the same time, the NPSHP value for the system must be determined. It must be greater than the NPSHR value for the pump. The minimum distance should be 0.5 m. If the NPSH value for the system (P) is less than the value for the pump (R), the pump will inevitably cavitate and suffer damage.
The operating range of a pump provides information about the pumpable volume flows, pressures (> vapour pressure) and temperatures (> pumping temperatures). The greater the operating range, the more flexible the pump. Because of their large speed range, twin-screw pumps have a very large operating range. They can therefore be used for a wide range of different media with different viscosities. With their large operating range, HYGHSPIN twin-screw pumps are also used to convey low-viscosity cleaning liquids such as water. This means that they can be used for CIP and SIP processes without additional bypasses.
Operational reliability describes the risk of failures. One of the factors contributing to the operational reliability of our HYGHSPIN twin-screw pumps is their unique modular design. The pump and motor shaft are centred on each other by positive locking, so that damage as a result of misaligned or warped couplings is not possible. Another feature of operational reliability is that the pumps are safe to run dry.
PC pumps make up part of the group of positive displacement pumps. They essentially consist of a fixed stator and a rotor, a type of screw that rotates longitudinally within the stator, pushing the medium forward. The stator and the rotor come into contact. As a result, the pumps react only slightly to changing viscosities or back pressures. However, the contact between the two also produces a defined wear of the stator, and hence continuous product contamination. In addition, there is only a very limited tolerance for dry running.
Pitting is a form of material breakdown on components and is typically a consequence of cavitation. In this process, particles of material are broken out of the component by microjets.
Positive displacement pumps work according to the what is known as the volumetric principle: a defined volume, also called displacement, is enclosed in the pump, displaced and expelled with higher pressure. The pressure is abrupt when the product is expelled. Ideally, the displaced volume is not affected by either its viscosity or by back pressure, but in reality there are often gap losses. The classic example of a positive displacement pump is the piston pump. Other well-known positive displacement pumps include rotary lobe pumps, PC pumps, circumferantial piston pumps and twin-screw pumps.
Positive locking refers to a joining technique in which the joined parts cannot move against each other because they are prevented from doing so by the geometry of the components (e.g. an indentation or serration).
For pumps, the pressure difference indicates the difference between the inlet and outlet pressure, i.e. the pressure increase achieved by the pump. For centrifugal pumps, a delivery head, from which the pressure difference for the pumped medium in question can be calculated, is usually specified.
A pressure pulse is a sudden abrupt increase in pressure within a system that can cause damage to the pump or other components of the system. HYGHSPIN twin-screw pumps are not subject to fluctuations. They are effectively pulsation-free, so that no pressure pulses occur in the system.
The pressure side is the point on the pump where the medium coming from the suction side exits into the piping after being transported into the pump chamber by the rotating pistons or spindles inside it.
Pulsations are regular pressure fluctuations within a system. They are often generated by positive displacement pumps. They are a consequence of the different operating phases (suction, displacement, discharge) and the resulting uneven volume flow of these pumps. Pulsation dampers can be used to mitigate pulsations. HYGHSPIN screw pumps cause practically no pulsations, as there is a uniform volume flow into and out of the pump.
The pump chamber in a pump is where the actual pumping process takes place. A distinction is often made between the suction, the pump and the pressure chamber in a pump, all of which are found inside the pump.
A pump curve is a graphic representation of the ratio of delivery head to pumping volume. The curve is determined by a test programme and provides information about performance.
Pump orientation is the orientation of the pump towards the system and towards the motor via the coupling. The aim is to integrate the pump into the system without twisting. Twisting can lead to excessively high stresses on the pump, resulting in damage.
The pumping temperature refers to the temperature of the medium to be pumped. As the pumping temperature rises, the demands on the pump increase, for example on the ,mechanical seals, and where there are high temperatures or chemical substances in play, also on explosion protection. The pumping temperature can increase as a result of a pumping process and depends on the pump design and operating situation.
The pumping volume indicates how much of a particular medium can or should be transported by the pump in a defined time. It depends on various factors such as pressure, pump design and the viscosity of the medium.
Ra is the abbreviation for roughness average, a measurement of the quality of a surface. The Ra value indicates how smooth a surface is. The lower the Ra value, the finer the surface. This makes cleaning easier and prevents contamination. Hygienic pumps normally have roughnesses of less than 0.8 µm. For particularly delicate products, for example in the pharmaceutical industry, the requirements are even higher. HYGHSPIN twin-screw pumps with roughnesses of less than 0.4 µm are available for these products.
Rotary lobe pumps make up part of the group of positive displacement pumps. They essentially consist of a housing and two counter-rotating pistons. The rotation of the pistons conveys the medium into a pump chamber, and from there into the piping. The terms rotary lobe pump and circumferantial piston pump are often used synonymously. In the details of their design, there are however differences. Circumferantial piston pumps have an improved seal to the pump cover, reducing their internal reverse flow compared to rotary lobe pumps. As a rule, however, the pulsation level of circumferantial piston pumps increases.
In rotating conveyance, the pumped medium rotates with the rotors or impellers in the pump. This form of conveyance is widespread and is found in centrifugal, rotary lobe, circumferantial piston and sine pumps. The rotational speed of impellers or rotors is the decisive factor for the speed at which the product is conveyed. In contrast to this principle is the principle of axial pumping, as found in piston pumps or screw pumps. With axial movement of the product, the speed of the product inside the pump is significantly lower. The product is not thrown against the pump chamber and is transported much more gently.
Self-emptying is a design feature of pumps and typical for applications with high hygiene requirements, where product residues and cleaning agents should not remain in the pump. Many pumps are emptied by means of an additional connection through which the pump is drained by opening a valve. With HYGHSPIN twin-screw pumps, no additional emptying connection is required. They are self-emptying as standard because the axial connection on the cover is fitted at the lowest point on the pump and product residues can flow out of the pump through it.
A pump is said to be self-priming if it is capable of automatically raising the pumped medium up to the pump by evacuating (venting) the suction line and the associated build-up of negative pressure. By contrast, the suction lines in non-self-priming pumps must always be filled with the pumped medium. If the suction line runs to empty, a non-self-priming pump is not capable of refilling the medium.
A term used to describe the design of a mechanical seal. Unlike the cartridge design, only the static components of the mechanical seal are combined in a single component in a semi-cartridge design. The rotating components are assembled separately. A semi-cartridge design offers cost advantages over the pure cartridge variant. With HYGHSPIN twin-screw pumps, there are also advantages in terms of assembly, which is why only semi-cartridge mechanical seals are used here.
In connection with parts and components, the term service life denotes the time during which an element is ready for operation without downtime or failure due to maintenance or wear. When a system is idle, for example due to planned maintenance work, this is referred to as idle time.
So-called torque – the force – is transmitted to another component from the shaft end. A coupling is often used for this purpose. It is however also possible to mount the other component, such as a pump or fan impeller, directly on the shaft end. The result is often a shaft “journal”, in which case the term used is free shaft end.
The shaft seal is the seal on a rotating shaft at the passage through a static housing component. The purpose of shaft seals is therefore to seal a rotating component (the shaft) against a stationary component (the housing), preventing leakage both out of and into the pump. Shaft seals are a typical machine component. There are a large number of designs available, for example shaft seals, lip seals, stuffing box seals and mechanical seals.
SIP = sterilise-in-place – sterilisation of components within a system using superheated steam or hot water at a temperature of 100 to 145 °C. All HYGHSPIN twin-screw pumps can be both cleaned and sterilised without disassembly. This means that they come with both an SIP and a CIP function.
The speed range of a pump indicates how many revolutions the spindles or rotors perform within a unit of time and is an important performance characteristic for each of the pump types. The greater the speed range, the more flexibly the pump can be used, which means that the pump can be used to convey media of different viscosities.
Stainless steel is the term used to describe steels that are highly resistant to corrosion. Stainless steel is long-lasting and requires little maintenance, and is therefore one of the most important technical materials. In addition, workpieces made of stainless steel can be produced with very smooth, resistant surfaces with little roughness, allowing high hygiene requirements to be met. Stainless steels are alloys of various metals – predominantly iron – and carbon. Typical key alloy components are chromium, nickel and molybdenum. The material is divided into groups according to its composition. Traditional designations for frequently used alloy groups are V2A and V4A. Today, stainless steels tend instead to be referred to by so-called material numbers, as these numbers provide more precise information about the composition and properties of each stainless steel. HYGHSPIN twin-screw pumps are usually made of stainless steel with the material number 1.4404. For special requirements, however, materials of even higher quality can be used. In addition to the quality of the material, the way in which a stainless steel is processed is also crucial, particularly when hygiene requirements are considered. Components can be manufactured either by casting or by machining from solid material. In cast parts, gas pockets can cause the formation of cavities, which in conjunction with microfine cracks can become nests of germs during subsequent machining and lead to contamination. To avoid this, the parts of all HYGHSPIN twin-screw pumps that come into contact with the medium are machined from solid stainless steel. This more complex manufacturing process offers the highest level of hygiene. More information
Suction capacity is the ability of a pump to pump products upward on the inlet side of the pump. If a pump can independently vent (evacuate) a suction line that is not filled with liquid so that the pumped liquid enters the pump, it is called a self-priming pump. The suction capacity of a pump is not a general value, and depends instead on the general conditions in place. It is determined by the NPSH value for the system and the NPSH value for the pump under operating conditions. As a general rule, the suction capacity increases as the NPSH value for the pump decreases. HYGHSPIN twin-screw pumps have a high suction capacity of up to 9 m.
The system layout describes the design and function of a system. Jung Process Systems has its own design department and develops an individual approach for each customer for the optimum pump solution for a specific application, considering questions such as: Nature of the product? Viscosity range? Frequent product change? Hygiene requirements? Special requirements? Required production volumeproduction volume? CIP / SIP integrated? Piping in place? Overall height and available space? Mobile use?
The term turbulence refers to local, in most cases chaotic flow conditions, for example vortices. Within turbulence, the local flow velocity can be significantly higher than the average flow velocity. This reduces the local static pressure, allowing vapour bubbles to form. Turbulence is therefore often the starting point for cavitation.
Twin-screw pumps make up part of the group of positive displacement pumps. Originally, these pumps were primarily used to convey oil products. With its many advantages in terms of process engineering and hygiene, the principle behind these pumps has however now become firmly established in food and beverage production and in the pharmaceutical, cosmetics and fine chemicals sectors. In the twin-screw version, a left-hand and a right-hand feed screw rotate against each other and displace the medium in the axial direction. This form of axial pumping is particularly gentle on the product, as the medium is not centrifuged or, as is the case with centrifugal and rotary lobe pumps, deflected. There are no major mechanical or thermal stresses on the product and the low level of pulsation also goes easy on the production line as a whole. The high suction capacity of twin-screw pumps, which is characterised by low NPSH values and works to counteract cavitation, should be emphasised. Twin-screw pumps can cover a very large volume flow and viscosity range. This means that it is not only possible to convey low and high viscosity products – including with low gas content – with one and the same pump, but that it can also be used to carry out CIP cleaning. This saves space and money, because there is no need to install a second pump for CIP and SIP, reducing expenditures on measuring, control, piping and valve systems, and on cabling. Twin-screw pumps operate with very little wear. The running spindles do not come into contact and are designed to be wear-resistant, so that abrasion and the associated risk of contamination of the pumped medium are completely avoided. Screw pumps developed under the HYGHSPIN brand name meet very high quality standards. In accordance with the rules of hygienic design, they are made entirely of stainless steel. In a special and unique manufacturing process, all parts that come into contact with the media are made of solid stainless steel, and therefore meet the most stringent hygiene requirements. HYGHSPIN twin-screw pumps are the natural choice for demanding pumping jobs. They are used for example to convey processed cheese, fondant mass, viscous dough, sausage meat, whole egg, frozen orange juice concentrate or yeast cultures. In the personal care and pharmaceutical products sector, HYGHSPIN twin-screw pumps ensure excellent quality in creams, toothpastes, body lotions and medicines sold to customers.
Vapour bubbles form when the local static pressure falls below the evaporation pressure of the medium. This can occur at a temperature as low as around 20 °C. Inside the pump, the vapour bubbles return to areas with higher pressure, where they suddenly burst. This creates so-called microjets, which place a very high local strain on the components. Over time, this results in damage and premature wear of the pump. The occurrence of vapour bubbles in the suction chamber in a pump should be avoided at all costs with an appropriate system layout and an NPSH value appropriate to the pumping jobs, as vapour bubbles constitute the main cause of cavitation. The crucial factor is the vapour pressure curve for the pumped medium.
The term vapour pressure refers to the absolute pressure at which the pumped medium begins to boil or evaporate at a certain temperature. In pumps, the vapour pressure of the pumped medium should not be reached at any point, and certainly not exceeded. The pressure at the pump inlet must be higher than the vapour pressure of the pumped medium, as otherwise there is a risk of cavitation. The situation is assessed using the NPSH values.
A vapour pressure curve refers to a specific pumped medium. It shows the progress of the vapour pressure as a function of temperature. As temperatures rise, so does the curve.
Viscosity describes the flowability of a medium, or more precisely the resistance of a medium to shearing (shear distortion). The higher the viscosity, the more viscous the medium and the poorer its flow properties. Viscosity is often expressed in “mPas”, “cP” or “mm²/s”. Water at 1 mPas and juices at approx. 5 mPas are among the low-viscosity media. Examples of highly viscous media include butter or silicone, with viscosities above 100,000 mPas. These products do not flow in independently and must instead be fed into the pump under pressure or by feeding equipment. Viscosity has a big influence on the flow behaviour of products, and hence on the pumping characteristic of pumps. As viscosity rises, the pressure losses in the line increase significantly. The influence of this should not be underestimated. The suction lines in pumps are particularly critical, as any pressure losses occurring here can lead to problems with cavitation. To further complicate matters, the NPSH values increase with the viscosity of the pumped medium. For a pump to be used as flexibly as possible, it is crucial for it to have a wide viscosity range to ensure that as many media of different viscosities as possible can be pumped with just one pump – ideally including the liquid used for CIP cleaning. All HYGHSPIN twin-screw pumps have a wide viscosity range and can also be used for CIP and SIP processes. In addition, the requirements for the NPSH values are lower compared to other pump designs. For special requirements, there is also the HYGHSPIN Hopper, a pump which thanks to its 3-in-1 technology can draw in highly viscous products without additional feeding.
The volume flow rate the volume of a medium that is conveyed in a specific time through a specific cross-section, for example in a pipe. HYGHSPIN twin-screw pumps have a wide speed range, making it possible to achieve both small and large volume flows with a single pump by adjusting the speed.
The volumetric efficiency of a positive displacement pump describes the ratio between the theoretical displacement and the real volume flow rate through the pump in percentage terms. The greater the volumetric efficiency, the more effective the operation of the pump. As a result of friction losses, the overall efficiency of the pump is lower than the volumetric efficiency.
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