No fuel residueNo fuel residueBecause the magnetic coupling is sealed, the fuel does not come into contact with the atmosphere. The heavy fuel oil cannot react with the oxygen in the air to form carbon deposits that can damage the ball bearing. This eliminates one of the major causes of pump failure.
FunctionFunctionThe rotation of the electric motor is transferred through the magnetic coupling to the pump screws without contact. The electric motor and the pump shaft each have a rotor with several magnets. During operation, the two rotors run in synchronized rotation.
Hermetically sealedHermetically sealedThe containment can is the sealing element of the KRAL pump. It encapsulates the pump shaft and inner magnet hub. If, in the illustration, you cover the outer rotor on the shaft of the electric motor, the fully encapsulated nature of the pump becomes apparent.
The magnetic coupling has no wearThe magnetic coupling has no wearThe magnetic coupling is a contact free component. The pump screws are driven without contact by the magnets on the outer and inner rotor. As there is no friction, there is no wear.

KRAL Screw Pumps with Magnetic Coupling

No more mechanical seal problems

KRAL screw pumps are also available with magnetic seals. Magnetic coupled pumps from KRAL are maintenance free, hermetically sealed and can be used at temperatures of up to 300 °C. Additionally, the lifespan of the ball bearings is considerably extended.

Operation, materials, components

  • Delivery rate: 5 to 3,500 l/min
  • Max. differential pressure: 100 bar
  • Temperature range: -20 °C to 300 °C
  • Housing: Nodular cast iron EN-GJS-400, steel and aluminium
  • 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

Leakage-free and clean

Critical fluids containing substances endangering the health or the environment should not leak to the atmosphere. Conventional shaft seals are lubricated by the fluid. A leakage flow is specified and necessary for proper operation. Magnetic couplings replace conventional shaft seals. KRAL screw pumps with magnetic coupling are hermetically sealed. The environment remains clean.

Can be used up to 300 °C

Thermal distortion and the temperature limits of elastomeric sealing elements restrict the use of screw pumps in high temperature applications. If temperatures up to 300 °C are handled, KRAL screw pumps with magnetic coupling are the right choice.

Reduced lifecycle costs

Spare parts and maintenance costs of mechanical seals increase lifecycle costs. The use of high quality mechanical seals in KRAL screw pumps is the standard. Even when properly applied, mechanical seals are subject to wear. Spare parts and maintenance costs arise. KRAL screw pumps with magnetic couplings are maintenance free, due to the lack of a mechanical seal and increased life of the ball bearing. The cost premium of a KRAL screw pump with a magnetic coupling will be typically amortized after only three years of operation.

Protection of delivery medium

With conventional seals, oxygen from the atmosphere may diffuse through the sealing gap into the fluid. When the fluid crystallizes from contact with oxygen, the process is interrupted and expensive plant shutdowns can result. KRAL screw pumps with magnetic coupling are hermetically sealed and protect the integrity of the fluid.

Low price

A magnetic coupling is required to transmit high torques. This can make the magnetic coupling large and expensive. For high torque transmission, strong magnets are necessary. The new generation of KRAL screw pumps are cost-optimized and designed to the requirements of the magnetic coupling. For many years, KRAL has successfully manufactured magnetic coupled screw pumps. Experiences and actual field-tested applications were incorporated in the design.

Overload protection

If the operating limits are exceeded, the screw pump may become damaged. Solids in the fluid can lead to blockages and damage the screw and the housing. In most cases, the product produced is not to specification, and the screw pump must be replaced. If the decoupling is controlled, and the screw  pump stops, the screw pump and magnetic coupling will suffer no damage. The magnetic coupling can prevent consequential damage.

Your advantages

  • Leak-free – no collection of residues
  • Extremely low maintenance
  • Hermetically sealed – prevents contact with oxygen of the heavy fuel oil, isocyanates, and other reactive liquids
  • Operating temperatures up to 300 °C
  • High flow and pressure capability
  • Technical data
    Technical data5-4255-118160-275370-450550-660
    Qth (1450 min-1, 0 bar)l/min5-4359-119166-282368-448543-668
           
    Pressurebar1616161616
           
    Temperature°C300300300300300
           
    Viscosity*mm²/s     
    min. 22222
    max. 10,00010,00010,00010,00010,000
           
    Speed*min-1     
    50 Hz 2,9002,9002,9002,9001,450
    60Hzup to3,5003,5003,5003,5001,750
    Inlet pressurebar1616161616

    *Please ask for other data. Technical data, dimensions and weights apply for the K series. For higher pressures of up to 100 bar and flow rates up to 2,900 l/min, please provide application information for the L and C series.

  • Models
    KF flange screw pump with magnetic coupling

    Universal pump for horizontal installation.

    KV pedestal screw pump with magnetic coupling

    The right choice if the installation area is narrow or if there is not enough available space for large pumps.

    KFT screw pump with overhead DIN flanges with magnetic coupling

    For horizontal or vertical installation.

    LFT screw pump with overhead DIN flanges with magnetic coupling

    For horizontal installation.

    LVI pedestal screw pump with magnetic coupling

    The right choice if the installation area is narrow or if there is not enough available space for large pumps.

    LVT pedestal screw pump with magnetic coupling

    Space saving pump for vertical installation.

    LFI flange screw pump with magnetic coupling

    Universal pump for horizontal installation.

    Flange screw pump CGF with magnetic coupling

    Universal pump for horizontal installation.

    CG pedestal screw pump with magnetic coupling

    Space saving pump for vertical installation.

    CL flange screw pump with magnetic coupling

    Universal pump for horizontal installation.

    Single pump station EKL11/EKS11 with magnetic coupling

    The single pump station EKL11/EKS11 consist of a screw pump K series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility. More options on request.

    Single pump station EKL12/EKS12 with magnetic coupling

    The single pump station EKL12/EKS12 consist of a screw pump K series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator. More options on request.

    Single pump station EKL13/EKS13 with magnetic coupling

    The single pump station EKL13/EKS13 consist of a screw pump K series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator and a gas / air separator. More options on request.

    Single pump station EKL14 with magnetic coupling

    The single pump station EKL14 consist of a screw pump K series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator, a gas / air separator and a KRAL flowmeter. More options on request.

    Single pump station ELL11/ELS11 with magnetic coupling

    The single pump station ELL11/ELS11 consist of a screw pump L series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility. More options on request.

    Single pump station ELL12/ELS12 with magnetic coupling

    The single pump station ELL12/ELS12 consist of a screw pump L series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator. More options on request.

    Single pump station ELL13/ELS13 with magnetic coupling

    The single pump station ELL13/ELS13 consist of a screw pump L series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator and a gas / air separator. More options on request.

    Single pump station ELL14 with magnetic coupling

    The single pump station ELL14 consist of a screw pump L series with built-in safety valve, largely sized strainer and delivery ball valves as well as pressure and vacuum gauges with shut-off facility with an additional pressure regulator, a gas / air separator and a KRAL flowmeter. More options on request.

    Double stations DKC and DLC with magnetic coupling

    The compact double stations DKC and DLC consist of two screw pumps, station block, hoisting eye, suction-side pressure gauge, strainer cover, pressure-side pressure gauge, reversing valve lever, vent valve, pressure connection and suction connection. More options and magnetic coupling on request.

    Double stations DS1, DS3, DS4, DL3, DL4 with magnetic coupling

    The double stations DS1, DS3, DS4, DL3, DL4 consist of two screw pumps , two strainers, two non return valves, overflow valve, two lockable vacuum gauges, lockable pressure gauge, oilpan and one lever control with counter flanges. More options and magnetic coupling on request.

    Double station DL2 with magnetic coupling

    The low pressure double station DL2 consist of two screw pumps, two strainers, two non return valves, overflow valve, lockable pressure gauge, oilpan and lever control with counter flanges. More options and magnetic coupling on request.

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