Proven KRAL pump quality suitable even for aggressive and contaminated media

In the new Z series, KRAL applies its expertise in pump design and technology to two screw pumps. As a result, the KRAL Z series is capable of delivering aggressive, low- or non-lubricating, and contaminated media with the reliability and quality that KRAL products are valued for by customers worldwide.


  • Very broad range of applications
  • Flexible connection arrangement
  • Excellent suction characteristics
  • Low-pulsation delivery
  • Adjustable screw design
  • Little space required
  • Dry running protection
  • Support for different delivery heights without booster pump
  • Optional delivery direction can be changed easily for a short time
  • No need for a separate stripping system with control unit
Data at a glance

Delivery rate
330 to 17,660 l/min or
20 to 1,060 m3/h

Max. differential pressure
25 bar

Temperature range
in the pumped media
-40 °C to +300 °C

Ductile iron or welded steel

Solid or engineered

Others on request

Device Group II, Device Category 2

Electrical, media or steam

Manufacturing according to
API 676 possible


The technical highlights at a glance

Pump housingPump housingThe unique delta design reduces internal flow losses and facilitates optimal suction performance. High viscosity media and brief phases with high gas content are no problem.
Variable screwsVariable screwsOptimized for fatigue strength. Application-specific protection against wear is also possible. Screws can be inserted as one-piece or multi-piece components.
Mechanical sealsMechanical sealsSingle- and double-acting mechanical seals depending on design and application. Can also be used with leakage monitoring and supply systems (API plans).
Optional leakage monitoring of mechanical sealsOptional leakage monitoring of mechanical sealsLeakage is conducted via a drain to a monitored reservoir.
Oil level checkOil level checkLong intervals between oil changes and low service costs, thanks to external monitoring and replenishment of hermetically sealed oil chamber.
Precision gearsPrecision gearsHardened and tempered precision gears can be positioned exactly for reduced backlash and increased efficiency.
Bearing housingBearing housingLarge bearing housing with adequate cooling capacity, even without external cooling system. Both bearing sides are lubricated with oil. In the event of high pump loads, the lubricating oil can be cooled using an additional heat exchanger.
External bearingsExternal bearingsThe external, application-optimized bearing concept ensures a long lifetime.
Bearing spacingBearing spacingBearings are spaced much closer together and screws are reinforced, thereby increasing the differential pressure capacity.
Integrated housing heaterIntegrated housing heaterInnovative heating jacket designed for optimal heat transfer for high viscosity media.
Optional integrated circulation valveOptional integrated circulation valveA spring-loaded overflow valve integrated in the housing protects the pump’s differential pressure and prevents pumped liquid from entering the housing.
Maximum flexibility by unlimited options for connection arrangements

Pumps are often built into existing systems, where predetermined installation conditions can easily become a problem. The KRAL Z series offers the solution with a unique innovation for screw pumps. The connections can be flexibly arranged both horizontally and vertically. The installation options are therefore unlimited.


Both installation variations are designed with external bearings so that the bearings don’t come into contact with the liquid. This significantly increases their lifetime. The mechanical seals are located on the suction side of the pump flow and are cooled and lubricated by the pumped liquid. Both single- and double-acting mechanical seals can be used in combination with an extremely broad range of seal supply systems. Different materials can be used in the design, depending on the pumped liquid.

Horizontal installation

Horizontal installation makes the pump very easy to service without separating the pump from the pipe system. This installation has a positive effect on thermal performance.

All the connections can be arranged horizontally (inline) and at several angles.

Horizontal installation
Vertical installation

The benefit of this design is its very compact layout, which makes it ideal for systems with limited space. It is installed via a pedestal, and the motor is mounted over the pump with a motor support.

All the connections can be arranged vertically (inline) and at several angles.

Vertical installation

The diagrams only show a few examples of connection arrangements. The design possibilities are extremely variable.

Examples of connection arrangements

Examples of Applications for the KRAL Z Series

Can be used in many different industries while offering excellent control behavior at different pressures and viscosities. The pump is dry-running-capable at all levels and offers optimal performance


Short reaction times. Fast and competent

Installation and commissioning

We can help you install and commission your KRAL products upon request. Professional installation and optimal deployment of the pumps are prerequisites for error-free operation. Our technicians not only know our products; they also know how the system affects the pump and can configure the latter accordingly for optimal performance. As a customer, you benefit from our wealth of experience, because we’ve commissioned large numbers of KRAL pumps at our customers’ premises.


KRAL training provides you with in-depth knowledge on installing, commissioning, and maintaining your KRAL product. You receive expert information from the manufacturer on how to install and commission your KRAL product properly, and you learn about various applications and utilization limits. You also learn to identify and rectify faults based on actual damage profiles. We lead you through a professional maintenance routine and show how you can reduce your product’s operating costs. The training can be held either at our headquarters in Lustenau or at your premises, upon request.

Maintenance and repair

Downtime can generate substantial costs. Increase the operational safety and minimize the life-cycle costs of your KRAL product through the preventative maintenance services provided by our competent service team. When a breakdown occurs, our service technicians react quickly and arrive at your premises in no time. When you make a repair shipment, confirmation of receipt is sent to you as soon as the shipment arrives. Each time a repair is made, we send you a comprehensive technical report together with detailed images. We perform maintenance work and repairs at our headquarters in Lustenau or at your premises, upon request. And the genuine KRAL parts we use guarantee the highest standards of quality.


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