Venting the seal chamberVenting the seal chamberThe seal chamber has a separate vent hole. This allows the pump to be vented easily and correctly during startup.

Wear reducing surface treatmentWear reducing surface treatmentA special heat treatment of the pump housing minimizes friction and wear.

Optimal cooling and lubricationOptimal cooling and lubricationThe application specific design of the balancing cylinder ensures proper cooling and lubrication of the sealing surfaces of the mechanical seals.

Self-purgingSelf-purgingVenting between the positive pressure side and the negative pressure side directly depends on the mechanical seal. In this way, it’s ensured that the air buffer through the medium in the vent line can be eliminated, even for vertical installation.

KRAL K Series Screw Pumps.

Universally applicable screw pump.

For pumped media up to 16 bar.
One of our best-selling products: compact and universally applicable, reliable and efficient. These are the KRAL screw pumps of the K series. Their housing is made from nodular cast iron and they have a sealed, lifetime-lubricated, service-free external bearing. The KRAL K series screw pumps are approved for use on board ships.

To Serial Production Program

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K Series Screw Pumps Overview Screw Pumps Série K Pompes à vis Apercu Pompes a vis Przeglad Pompy srubowe Vista general Bombas de husillo roscado Visao geral Bombas parafuso Обзор Винтовые насосы

Operation, materials, components.

Delivery rate: 5 to 2,900 l/min.
Delivery rate KFT: 5 to 510 l/min.
Max. differential pressure: 16 bar.
Temperature range: -20 °C to 180 °C, magnetic coupling to 300 °C.
Viscosity: 10,000 mm²/s.
Housing: Nodular cast iron EN-GJS-400.
Screws: Steel, nitrided.
Approvals: ABS, BV, CCS, DNV, GL, LRS, MRS, NK, RINA.
ATEX: II 2 GD b/c group II, category 2.
Heating: Electrical, media or steam.

Advantages of the KRAL K series screw pumps.

Suitable for many applications, very compact, robust, flexible, excellent price-performance ratio. Perfectly adequate for pressures up to 16 bar. All products of the K series have an internal safety valve and can be ordered with DIN flanges in inline arrangement (except KFT and KFN). Like all KRAL screw pumps, the pumps of the K series are self-priming, deliver with low-pulsation and, in contrast to other functional principles, can be easily regulated.

Advantages of the KRAL screw pumps.

Compared to other types of pumps, KRAL screw pumps convey a wide variety of media, qualities and viscosities in consistently high quantities, even at high differential pressure. Further advantages are the compact design and the high flexibility.

Find out more

Stop coupling damage.

With some liquids, residue can build up, which may cause the pump to fail. A typical spot for residue to build up is at the mechanical seal. The residue damages the ball bearing, which runs hot, melts the elastomeric ring and damages the coupling. With the K series screw pump, there is a weep hole next to the mechanical seal, to prevent the fluid from collecting and building up as residue.

KRAL offers the advanced quality of SiC mechanical seals, which contain graphite, as a solid lubricant to reduce the coefficient of friction in dry running conditions. The O rings with high fluorine content are suitable for higher temperatures and are chemically stable. The K series screw pump offers innovative seal concepts. A proven selection of radial rotary shaft seals, mechanical seals and a hermetically sealed magnetic coupling are available as standard. A robust and compact design rounds off the profile.

Your advantages.

No coupling damage through well placed leakage hole.
Safety reserve in dry running.
Viscosity of 10,000 mm²/s.
Differential pressure: 16 bar.
Low service operation.
DIN standard.

Technical data.

Technical data		15-42	55-118	160-275	370-450	550-660	851-1301	1500-1700	2200-2900
Qth (1450 min^-1, 0 bar)	l/min	15-42	55-118	160-275	370-450	550-660	851-1301	1500-1700	2200-2900

Max. pressure at pressure flange	bar
K		16	16	16	16	16	16	16	16
KFT		16	16	16

Temperature	°C
with NBR rotary lip seal		90	90	90	90	90	90	90	90
with FKM rotary lip seal		150	150	150	150	150	150	150	150
with mechanical seal standard		150	150	150	150	150	150	150	150
with mechanical seal hard material		180	180	180	180	180	180	180	180
with magnetic coupling		300	300	300	300	300	300	300	300

Viscosity	mm²/s
min.		1.1	1.1	1.1	1.4	1.4	1.4	1.4	1.4
max.		10,000	10,000	10,000	10,000	10,000	10,000	10,000	10,000

Max. pressure at suction flange	bar
with rotary lip seal		1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5
with mechanical seal standard		6	6	6	6	6	6	6	6
with mechanical seal hard material		10	10	10	10	10	10	10	10
with magnetic coupling		10	10	10	10	10	10	10	10

Models.

KF flange screw pump.
Universal pump for horizontal installation, other mounting solutions possible.

KH foot screw pump.
Mounted horizontal onto base frames.

KV pedestal screw pump.
The right choice if the installation area is narrow or if there is not enough space available.

KFT screw pump with overhead DIN flanges.
For horizontal or vertical installation.
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Operating instructions.

Operation, materials, components.

Advantages of the KRAL K series screw pumps.

Advantages of the KRAL screw pumps.

Stop coupling damage.

Your advantages.

Instruction video.