HeatingHeatingElectrical or medium heating for the preheating of highly viscous fluids.
Expansion valveExpansion valveTo prevent an unacceptably high internal pressure within unused parts of the block due to heating and thermal expansion, the switch valve cylinder has two small expansion valves.
Different fluidsDifferent fluidsA two-way valve can be switched manually, electrically or pneumatically, allowing for switching between two types of fuel.
Pump variationsPump variationsDouble stations can be set up with KRAL pumps for pressures up to 40 bar.

KRAL Pump Stations DKC / DLC / DS/L

Two pumps provide more than double the advantages

Maximum operational reliability with a standby screw pump
There are critical applications in which a second screw pump is prescribed for security. Typical examples are booster modules of oceangoing ships, and burner stations in marine and industrial applications. Maximum reliability is required. The most common operating mode is therefore that one screw pump is running and the other is switched off (standby).

Operation, materials, components

  • Delivery rate: 5 to 280 l/min
  • Max. differential pressure: 40 bar
  • Temperature range: -20 °C to 180 °C
  • 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

In the case of a ship, the failure of the fuel screw pump in the booster module means that the engine comes to a standstill. If the flame goes out in a burner, a production process will be interrupted or a heating system will fail. Such applications require security. For maintenance, the primary screw pump can be switched to the standby screw pump, without interruption.

Cost reduction through many functions in compact space

If a second screw pump is necessary, it soon becomes clear that the cost of design, pipework and control is considerable. The space requirement for a structure involving individual components is also very large. A significantly more economical solution is represented by the completely newly developed DKC and DLC dual stations by KRAL. Two screw pumps of the K series up to 16 bar or L series up to 63 bar are fitted to one block. The block integrates all functions within minimum space, and is available with many further options.

Light and heavy fuel oil operation

For alternate operation with two liquids, the operator does not need to do expensive pipework. As an option, a liquid changeover switch can be fitted. In this way, KRAL dual stations are connected to two pipeline systems with different liquids. Switching between the liquids is manual, electrical or pneumatic. For remote monitoring of the lever position, limit switches are available.

Service without stopping the screw pump

Reliability through a standby screw pump which is always available is the basic idea of the dual station. In this way, maximum reliability is ensured. After the changeover, the switched-off port of the station block is depressurized and the screw pump can easily be removed. The ship’s engine continues to run, the production process is not interrupted, the heating system continues to operate.

Extremely easy installation

KRAL dual stations are quickly set up and fixed. In the simplest case, the suction and pressure lines have to be connected. Done! In the case of systems with two different liquids, there are two pipelines. The connections for the suction and pressure sides are at the front, so they are easy to reach. In contrast to the traditional structure involving two individual screw pumps, apart from connecting the suction and pressure lines no development, design or pipework is required. That saves a lot of time and money.

Compact, space-saving design

The design of the new dual stations reduces the space requirement for all applications with two screw pumps considerably. Nothing remains as it was in the previous model. Implementing new ideas and new technological possibilities, KRAL has completely redesigned the station block and the components. Its compactness has reached the limit of what is technically feasible.

Highest flow rates on demand

The dual stations DKC and DLC are eminently suitable for simultaneous operation of two KRAL screw pumps of the K or L series. By parallel operation of both screw pumps, the flow rate can be doubled.

Many useful options are available:

  • Heating variants for heating highly viscous liquids
  • Two-way valve for switching between liquids
  • Pressure-retaining valve for constant feed pressure
  • Pressure switch for monitoring pressure
  • Differential pressure display for monitoring the loading of the strainer
  • Temperature measurement of the liquid
  • Monitoring leaked oil
  • Strainer cover protection to prevent accidents caused by oil being sprayed out


Accessory: KRAL precision flowmeters OMA series

Maintenance work without downtime. KRAL double stations DL/DS make it possible

KRAL block aggregates stand out for their ready-for-connection, compact construction. Both of the installed KRAL screw pumps are self-priming pumps with low pulsation and operate at a low noise level. Switching over from the operating screw pump to the reserve screw pump can be carried out electrically or manually. Screw pump maintenance and filter cleaning can be performed without interrupting operations.

KRAL double stations in block execution are especially used in oil firing service for delivering heating oil, circular pipeline transfer screw pumps and burner screw pumps for industrial furnaces, in public buildings, in the ship building industry, and anywhere a continuous supply of oil is required.

Your advantages

  • High operating safety
  • More functions
  • More safety with two screw pumps
  • 50 % less space requirement
  • Simple installation
  • Available with magnetic coupling
  • Technical data

    DKC series

    Technical data5-4255-118
    Qth (1450 min-1, 0 bar)l/min5-4359-119
        
    Max. pressure at pressure flangebar  
    K 1616
    KFT 16 
        
    Temperature°C  
    with NBR rotary lip seal 8080
    with FKM rotary lip seal 150150
    with mechanical seal standard 150150
    with mechanical seal hard material 180180
    with magnetic coupling standard 180180
    with magnetic coupling high temperature 250250
        
    Viscositymm²/s  
    min. 22
    max. 10,00010,000
        
    Max. pressure at suction flangebar  
    with rotary lip seal 66
    with mechanical seal standard 66
    with mechanical seal hard material 66
    with magnetic coupling 1616

    DLC series

    Technical data5-1015-2632-5455-85
    Qth (1450 min-1, 0 bar)l/min5-1015-2632-5858-84
          
    Max. pressure at pressure flangebar63636363
          
    Temperature max. pumped liquid°C    
    with radial shaft seal NBR 80808080
    with radial shaft seal FKM 150150150150
    with mechanical seal standard 150150150150
    with mechanical seal hard material 180180180180
    with magnetic coupling *     
          
    Viscositymm²/s    
    min. 1.51.51.51.5
    max. 7,0007,0007,0007,000
          
    Max. pressure at suction flangebar    
    with radial sealing ring 6666
    with mechanical seal standard 6666
    with mechanical seal hard material 6666
    with balanced mechanical seal     
    model LFI/LFT/LFW/LVI/LVT 20202020
    model LFM  6666
    with magnetic coupling *     
          
    * customer-specific, contact KRAL     

    DS/L series

    Technical data5-1015-2632-54
    Qth (1450 min-1, 0 bar)l/min5-1015-2632-57
         
    Max. pressure at pressure flangebar666
         
    Temperature max. pumped liquid°C   
    with radial shaft seal NBR 808080
    with radial shaft seal FKM 150150150
    with mechanical seal standard 150150150
    with mechanical seal hard material 180180180
         
    Viscositymm²/s   
    min. 1.11.11.1
    max. 7,0007,0007,000
         
    Max. pressure at suction flangebar   
    with radial sealing ring 0.50.50.5
    with mechanical seal standard 666
    with mechanical seal hard material 666
  • Models
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