Alfa Laval LKH Evap Low-NPSHr Evaporator Pump

Alfa Laval LKH Evap low-NPSHr evaporator pump

The Alfa Laval LKH Evap is an LKH-based hygienic centrifugal pump tailored for evaporation duties. It combines a low required NPSH with high efficiency and a scraper impeller called ClearFlow, which addresses product build-up in high-solids applications. Seven Star LLC supplies the LKH Evap in Oman and the GCC as an independent supplier in Muscat.

Evaporator extraction is one of the harder jobs for a pump, since the liquid is at or close to its boiling point under vacuum and the available suction head is small. The Evap designation tells you that the pump is documented and configured for that situation, not just for general hygienic transfer.

LKH Evap technical specifications

How the LKH Evap suits evaporation duty

Low NPSHr is the central feature. The special vane form of the semi-open impeller lowers the suction head the pump needs, so the evaporator can be positioned with less elevation above the pump, or can run at a lower pressure without cavitation. That is also the reason the supplier backs the pump with a vacuum curve package.

ClearFlow, the scraper impeller, tackles the layer of product that can form at the impeller inlet when the liquid is concentrated and sticky. By limiting that layer the plant can run longer between cleanings, which improves production time.

The remainder follows the LKH concept: balance holes around the shaft seal reduce axial thrust and improve seal cooling, and a compression coupling joins the stub shaft and motor shaft with precise alignment, reducing noise and vibration.

Where the LKH Evap fits in the LKH range

The LKH Evap is for the concentrate and condensate sides of an evaporation or powder-processing plant, and for plant and equipment dewatering. Other LKH pumps handle general transfer. A filtration booster would use the LKHPF, and air-laden suction would call for LKH Prime. Because the shaft seal is the same across 11 LKH models, spare seals are not exclusive to the Evap.

Selecting and ordering the LKH Evap

• Evaporator operating pressure and liquid temperature to determine the NPSH available.
• Flow and head at duty point and the supply frequency.
• Viscosity and solids content of the concentrate, which decide whether the scraper impeller is relevant.
• Seal type: single, flushed or double.
• Elastomer grade for the product and cleaning chemicals.
• Motor and base arrangement.

Installation, commissioning and maintenance of the LKH Evap

Keep the suction line short, large in diameter, free of high points and pointing steadily down toward the pump, so the NPSH margin stays as large as possible. Use the vacuum curve package to check the margin at the lowest operating pressure rather than at normal conditions.

The shaft seal is replaceable in minutes thanks to its front-loading design. Alfa Laval offers service videos for single, flushed and double seals on the product page. Check seal faces after any event where the pump has run with vapour in the casing.

Cleaning and operating notes for the LKH Evap

Evaporator plants swing between concentrate production and intensive cleaning. The pump has to tolerate both, so check the cleaning chemicals, their temperature and the cycle length against the elastomer grade. Where the concentrate is very viscous, ask whether a different impeller diameter or motor size is advisable. Operating the pump far outside its curve, especially at a very low flow, raises the temperature in the casing and shortens seal life. A bypass or recirculation line sized for minimum flow is a normal safeguard.

Where the evaporator operates under a deep vacuum, inspect the pump casing joints and seal for air leakage, as a small leak can shift the whole operating point.

Why the vacuum curve package helps

A normal pump curve describes behaviour at atmospheric suction. An evaporator pump works at reduced pressure, so the engineer needs to know how much margin remains between the available and the required suction head across the whole operating window. Documentation of this kind lets the plant designer set the liquid level, the line size and the minimum operating pressure with confidence, and it gives the commissioning team a reference when the first runs show unexpected cavitation noise.

Typical applications in Oman and the GCC

Evaporation is used in dairy, juice concentrate, starch and sweetener, ethanol and chemical processing. In the Gulf region the relevant plants include dairy and food processors and chemical producers. Higher ambient and cooling-water temperatures reduce the margin in condensers and may lower the evaporator vacuum, which makes a careful NPSH check more important than at a cooler site.

LKH Evap against sibling LKH pumps

Information to send with an RFQ for the LKH Evap

• Part name LKH Evap.
• Operating pressure, temperature and fluid in the evaporator.
• Flow, head and frequency.
• Solids content and viscosity.
• Seal and elastomer options.
• Delivery location and date.

Site conditions in Oman for the LKH Evap

Pump selection in Oman has to account for the site, not only the duty point. Process liquids and cooling water can arrive warm in summer, which raises vapour pressure and reduces the available NPSH, so check the NPSH margin of the LKH Evap at the highest expected liquid temperature. Motors on outdoor skids also work in high ambient air, and their rating, enclosure and cooling should match that environment.

For hygienic and process plants in the Gulf, plan the spare parts that wear first, such as seals, O-rings and bearings, and keep the material certificates with the plant records. Sharing the fluid, temperature, flow, head and cleaning regime with the supplier at RFQ stage makes it easier to confirm that the LKH Evap is the right configuration before the order is placed.

Documents and quotation

Send us the part name and your evaporator conditions, and we will confirm which manufacturer documents, such as vacuum curves, are available.

Seven Star LLC will then prepare a quotation for supply in Oman and the GCC.