Table of contents □ About this document Removing the pump ▪ Removing the pump □ General information □ Target groups Operation □ □ Symbols Commissioning □ ▪ Safety instructions for commissioning Danger levels ▪ Protect the pump against soiling □ Associated documents ▪...
General information General information About this document The operating instructions form part of the pump or motor-driven pump. The operating instructions must be kept for future reference. Furthermore please observe the operating instructions for the drive motor. Target groups Target group Tasks □...
Installation, removal and installation work may only be carried out by specialist personnel. □ Do not use KRAL pumps outside the performance limitations specified on the rating plate and in the "Technical data" section. In the case of operating data that does not agree with the specifications on the rating plate, please contact the manufacturer.
Proper use Technical data KRAL screw pumps of the W series are used to deliver lubricating liquids or cutting emulsions and cutting oils. Both the concentration and the size of solid particles carried in the emulsion affect the service life of the pump. The maximum size of the particles should not exceed 70 µm. It is always to your advantage to use filters with a higher separation factor.
Required NPSH values Required NPSH values The following table shows the required NPSH values to ensure that the various pump sizes can be operated without cavitation. These values are derived from the pump kinematics during operation with a low-volatility pumped liquid such as lubricating oil or hydraulic liquid. The following examples indicate that when pumped liquids have a readily volatile component content the required NPSH values notably increase: □...
Noise levels Noise levels Max. noise level ± 3 dB(A) [dB(A)] W 15-20 W 32-42 W 55-85 W 105-118 W 160-210 W 235-275 Pump (at 2900 r.p.m.) Motor max. – at 40 bar – at 80 bar Pump + motor –...
General drawing of a screw pump General drawing of a screw pump Function description Fig. 1 Structure of a screw pump 1 Suction cover 6 Main screw 2 Back pressure valve 7 Mechanical seal 3 Pressure casing 8 Balancing cylinder 4 Leakage connection 9 Pump casing 5 Ball bearing...
Function description Function description Screw pumps belong to the rotating displacement group of pumps. In these pumps a special form allows an almost tight engagement of three intermeshing screws 6,10 to be achieved. Together with the pump casing 9 that encompasses the screw package, closed volumes are achieved by this means. The standard direction of rotation of the pump is clockwise as seen from the drive (indicated by an arrow on the pressure casing 3).
Back pressure valve Back pressure valve Fig. 3 Back pressure valve installation position 1 Adapter sleeve 3 Ball 2 Spring 4 Leakage To ensure the proper functioning of mechanical seals, they must be constantly lubricated by the pumped liquid. This also requires greater pressure on the liquid-filled inside of the seal than in the atmosphere. To ensure this even when the pump is installed above the liquid level, a spring-loaded back pressure valve is mounted in the relief line of the seal chamber.
Unpacking and checking the state of delivery Unpacking and checking the state of delivery Transportation, storage and disposal 1. On delivery unpack the pump/motor-driven pump and check for damage during transportation. 2. Report damage during transportation immediately to the manufacturer. 3.
Preservation Preservation Preserving the internal surfaces of the pump 1. Set up the pump so that the pressure-side connection is pointing upward. 2. Close the suction-side connection of the pump with a cover plate. 3. Pour non-corrosive, resin-free oil into the pressure flange until the oil reaches the pressure flange and the air bubbles stop rising, while slowly turning the main screw against the direction of rotation.
Installation, removal and connection Installing the pump KRAL pumps of the W series can be used vertically in any position. Operation in the horizontal position requires that the pressure connection of the pump is oriented upward, see Fig. 2, Page 15. W-pumps can be supplied for dry or wet installation.
Installation Protect the pump against soiling WARNING Damage through impurities in the piping system. ► During welding work attach cover plates in front of the connecting flanges. ► Ensure when welding that welding beads and abrasive dust cannot get into the piping system and the pump.
Installation Aligning and checking the shaft coupling Prerequisites: □ Pump, shaft coupling and motor have been mounted by the customer a Lateral offset b Angular offset c Linear offset Fig. 5 Measuring points for tolerances of the coupling alignment Coupling diameter Lateral offset a Angular offset b Linear offset c...
Electrical connection Electrical connection Connecting the pump Prerequisite: □ Sufficiently dimensioned cables DANGER Risk of death resulting from electric shock. ► The pump may only be connected by an authorized electrician. ► Ensure that the power supply is de-energized. ► Ground the pump carefully. 1.
Page 19
Removing the pump 1. In case of operation at higher temperatures wait until the motor-driven pump has cooled down to the ambient temperature. 2. Disconnect the pump from the power supply. 3. Open the terminal box at the motor. 4. Disconnect the connecting cable. 5.
Commissioning Commissioning Operation Safety instructions for commissioning The following instructions must always be observed. ► The pump may only be commissioned by authorized qualified personnel. ► Before commissioning, make sure that the pump is filled. Protect the pump against soiling The pump has to be protected against soiling during commissioning.
Commissioning DANGER Risk of death through emitted pumped liquid. Pumped liquids can be hot, poisonous or caustic and can spray out under high pressure. ► Wear protective clothing during all the work. Ensure face protection. ► Collect the emitted pumped liquid safely and dispose of it in an environmentally compatible man- ner.
Commissioning Prerequisite: □ Pump securely fastened □ Pump connection to the piping system is free of stress □ Pump motor is connected correctly to the electrical power supply □ Piping system is free of contamination □ A commissioning filter of the prescribed mesh width is fitted if the piping system is to be cleaned by the pump □...
During operation During operation Checking the operating pressure Fig. 3 Schematic diagram: Fig. 4 Schematic diagram: Open pressure gauge stopcock Close pressure gauge stopcock Pressure gauge stopcocks that are opened permanently can result in the pressure gauges leaking. ► Close the pressure gauge stopcocks after completing reading. ►...
Maintenance Maintenance Repairs Required maintenance The service life of the pump depends to a great extent on the operating conditions of the pump. If the operating limits are observed, see "Technical data", Page 6, the pump has a service life of many years. Signs of progressive wear of individual pump elements: Finding Cause...
Replacing the coupling Removing the torsionally elastic coupling Prerequisite: □ Pump dismantled, see "Removing the pump", Page 18 1. Before starting to dismantle, use suitable covers to protect the inlet and outlets opening of the pump against solid particles and soiling.
Replacing the coupling Installing the torsionally elastic coupling Prerequisite □ Replacement coupling available 5. Use light blows with a soft hammer to mount the motor-side coupling 052.2 on the shaft end of the motor. Heating the coupling to 80 °C - 100 °C facilitates mounting. 1.
Replacing the mechanical seal and ball bearing Removal of mechanical seal and ball bearing 6. Dismantle the supporting ring 055.2, parts of the mechanical seal 457 and supporting ring 055.3 from the main screw. 1. Remove the socket screws 914.2. 7.
Replacing the screw set Replacing the screw set Removing the screw set Prerequisite: □ Pump dismantled, see "Removing the pump", 3. Push the main screw with the mounted Page 18. mechanical seal into the seal casing 134. Use the mounting sleeve in the process. 1.
Replacing the screw set Installing the screw set Prerequisite: □ Replacement parts available 1. Press the balancing cylinder 042 onto the 7. Tighten the socket screws 914.2, see Tab. 1, main screw, mount the circlip 471.3. Page 38. 2. Clean the main screw around the mechanical seal carefully and grease it.
Replacing the Domsel type radial shaft seal Removing the radial shaft seal Prerequisite: □ Pump disassembled, see "Replacing the mechanical seal and ball bearing", Page 27, removal steps 1–5 2. Prepare a suitable rod for mounting the seal ring. The rod must lie flat on the support body of the seal ring and may not have any sharp edges in the vicinity of the sealing lip.
Information about faults Information about faults Troubleshooting Faults can have different causes. The following tables list the symptoms of a fault, the possible causes and measures for elimination. Possible faults Fault Cause / Elimination □ No pump suction 1, 2, 3, 4, 5, 6, 7, 8, 35 □...
Page 34
Information about faults Cause Remedy Viscosity of the pumped liquid too ► Increase the temperature of the liquid high - or - ► Reduce the rotation speed. Viscosity of the pumped liquid too ► Decrease the temperature of the liquid - or - ►...
Page 35
Information about faults Cause Remedy Cold start when delivering high- ► Install a pump heating. viscosity liquids Seal overload during ► To prevent thermal expansion of the liquid causing a heating process build-up of pressure, open the pressure- or suction- side shut-off devices.
Maintenance kits Maintenance kits Spare parts Notice: The maintenance kits contain only the numbered parts and are only supplied complete. W 15 – 118 165.1 165.2 901***** 739.1 914.1**** 471.2 914.2 739.1 471.3 471.1 055.1 055.2*** 894.1***** 739.2 055.3* 457* 745.1** 745.2** Qty.
Need help?
Do you have a question about the W Series and is the answer not in the manual?
Questions and answers