Alfa-Laval

Alfa Laval pumps run in dairies, breweries, soft drink bottling plants and pharmaceutical installations all over Europe. The shaft seal is the part that needs attention most often. On this page you’ll find out which Alfa Laval seal kits are available, what’s in them and how to choose the right kit for your pump.

What is an Alfa Laval seal kit?

Alfa Laval calls them service kits. A seal kit contains the wear parts of the shaft seal for one pump: the rotating and stationary seal rings and the matching O-rings. Some kits also include the impeller screw seal. With one kit you replace everything that wears in one go, without hunting for separate parts.

A kit is always tied to three things: the pump type, the seal arrangement (single, flushed or double) and the elastomer. Once you have those three details, you have the right kit.

Which Alfa Laval pumps?

Centrifugal pumps: LKH and SolidC

The LKH is Alfa Laval’s most widely used hygienic centrifugal pump. Handy for your stock: the same single shaft seal fits most LKH models and all SolidC pumps. The LKH Prime (self-priming), LKH UltraPure, LKH Evap and LKH Multistage variants also use seal kits from the same family.

MR liquid ring pumps

The MR is mainly used as a CIP return pump. Frequent switching and cleaning agents make the shaft seal wear relatively quickly here. Always keep a kit in stock for these pumps.

Positive displacement pumps: SRU, SX, OptiLobe, DuraCirc and OS

Rotary lobe pumps (SRU, SX and OptiLobe), the DuraCirc circumferential piston pump and the OS twin screw pump have two shafts, so two shaft seals per pump. The seal kits differ by frame size, so always give us the full type number, for example OS32 or SRU3.

Single, flushed or double

Alfa Laval pumps come with three shaft seal arrangements. On the LKH they’re interchangeable: with a conversion kit you can turn a single seal into a flushed or double arrangement.

• Single shaft seal: the standard. Suitable for most thin products and CIP liquids.
• Flushed shaft seal (quench): water flows behind the seal, with a lip seal as a second seal. Choose this for products that crystallise or cake, such as sugar solutions, or if the pump can run dry.
• Double mechanical seal: two seals with pressurised barrier fluid between them, usually supplied by a seal support system. For aggressive or toxic media and for applications where no product may leak out.

Materials

You’ll find an overview of all materials on our materials and seal faces page. These are the combinations you’ll come across most with Alfa Laval.

Seal faces

The standard combination on the LKH is a stationary ring with a silicon carbide (SiC) face running against a rotating carbon ring. For abrasive products or heavier duty, choose SiC against SiC. Carbon/SiC is more forgiving of brief dry running; SiC/SiC lasts longer with particles in the product. The metal parts of the seal are stainless steel.

Elastomers

• EPDM: the standard in dairy and beverages. Good resistance to hot water, steam and most CIP agents. Not suitable for oils and fats.
• NBR: for fatty products and oils, at lower temperatures.
• FKM (Viton): for higher temperatures, fats and many chemicals.
• FEP-encapsulated: a silicone or FKM core with an FEP jacket. For aggressive chemicals and solvents.
• FFKM: for the toughest chemical and pharmaceutical applications, available for the OS twin screw pump among others.

Working in the food industry? Then the elastomers must comply with FDA and EC1935-2004. Pharmaceutical installations often also require USP Class VI. We supply the kits with the matching certificates.

How to find the right kit

Send us the following details and we’ll look up the right kit for you:

1. The pump type and size from the nameplate, for example LKH-20 or SolidC-2.
2. The shaft seal arrangement: single, flushed or double.
3. The seal face combination: carbon/SiC or SiC/SiC.
4. The elastomer: EPDM, NBR, FKM, FEP or FFKM.
5. Do you have the Alfa Laval part number? Even better. LKH service kits usually start with 9611-92.

Not sure? Take a photo of the nameplate and the old seal. That usually gets us most of the way. You can also use our find your seal tool.

When should you replace the seal kit?

Replace the kit as soon as you see leakage along the shaft, or if the pump no longer stays dry after dry running or a pressure surge. Many plants also replace the kit preventively during annual maintenance or a production shutdown. That stops a leaking seal from bringing you to a halt in the middle of a production run. Always replace the O-rings too, even if they still look fine. Is the seal itself damaged? Then we’ll check whether refurbishment is possible.

Seal kits for Alfa Laval from Qseals

Qseals supplies seal kits for Alfa Laval pumps in the Netherlands and worldwide. Can’t see your kit straight away? We’ll offer an equivalent alternative in the same materials. Need a complete mechanical seal or help with another pump in your installation? We can help with that too.

Request a quote with your pump type and seal arrangement, or call us. You’ll quickly know what the kit costs and when you’ll have it.