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

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

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

Self-purging Self-purging Venting 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.

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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

Operation, materials, components.

Advantages of the KRAL K series screw pumps.

Advantages of the KRAL screw pumps.

Stop coupling damage.

Your advantages.

You have several options for finding the right operating instructions/product information sheet:

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OIK 14 | Screw pump | K | Mechanical Seal

OIK 07 | Screw pump | K | Radial shaft seal

OIK 09 | Screw pump | K | Magnetic coupling

OIK 10 | Pump station | EKL/EKS | –

OIL 01 | Screw pump | L | Mechanical seal / Radial Shaft Seal

OIL 02 | Screw pump | L | Magnetic coupling

OIL 03 | Pump station | ELL/ELS | Mechanical seal / Radial Shaft Seal

OIC 01 | Screw pump | CK | Mechanical seal / Radial Shaft Seal

OIC 02 | Screw pump | CL | Mechanical seal / Radial Shaft Seal

OIC 10 | Screw pump | CG | Magnetic coupling

OIC 13 | Screw pump | CL | Magnetic coupling

OIC 18 | Screw pump | CG | Mechanical seal / Radial Shaft Seal

OIM 01 | Screw pump | M | Mechanical seal / Radial Shaft Seal

OIM 05 | Screw pump | M | Magnetic coupling

OIN 04 | Screw pump | NS | Radial shaft seal

OIW 01 | Screw pump | W | Mechanical seal / Radial Shaft Seal

OID 02 | Pump station | DKC/DLC | Mechanical seal / Radial Shaft Seal

OID 03 | Pump station | DKC/DLC | Magnetic coupling

OID 05 | Pump station | DL2 | Mechanical seal / Radial Shaft Seal

OID 06 | Pump station | DL3/DL4/DS1/DS3/DS4 | Mechanical seal / Radial Shaft Seal

OID 07 | Pump station | DL3/DL4/DS1/DS3/DS4 | Magnetic coupling

OIO 08 | Flowmeter | OMH | –

OIO 14 | Flowmeter | OMG | –

OIO 15 | Flowmeter | OME | –

OIO 20 | Flowmeter | OME compact | –

OIO 23 | Flowmeter | OMP | –

OIO 28 | Flowmeter | OMX | –

OIO 30 | Flowmeter | OMS | Low-viscosity liquids

OIO 31 | Flowmeter | OMS | High-viscosity liquids

OIO 03 | Flowmeter | OMK | –

OIE 26 | Elektronics | BEM 100 | –

OIE 29 | Elektronics | BEM 100 | Support-Software Smart Support

OIE 29 | Elektronics | BEM 150 | Support-Software Smart Support

OIE 27 | Elektronics | BEM 150 | –

OIE 24 | Elektronics | BEM 200 | –

OIE 15 | Elektronics | BEM 300 | –

OIE 23 | Elektronics | BEM 300 | Modbus communication

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OIE 12 | Elektronics | BEM 500 | –

OIE 30 | Elektronics | Smart Solution Display | –

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OIG 01 | Screw pump | G | Mechanical Seal

OPR 01 | Screw pump | K | Product information sheet

OPR 02 | Screw pump | K | Product information sheet

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