Did you know that the reason the Waukesha Universal pump is call “Universal” is because it was one of the very first sanitary pumps to take both an o-ring seal and mechanical seal? We’ve talked about the available seal options for Universal 1 pumps in the past- single o ring, double o ring, single mechanical, and double mechanical seals. But in today’s post, we wanted to talk about a little known fifth seal configuration- the lip seal- and how we used it to help jump start a customer’s pump.
Recently, Triplex was approached by a lip balm manufacturer. They were in the process of installing a new filling line that would have a new filling pump, but they were having trouble with the feed pump on their old line. It was using a single o ring seal and wouldn’t seal. When we got onsite, we took the pump apart and inspected it. We found that the body o ring groove on the lower shaft had significant wear and the body was for all intents and purposes shot.
In a single o ring seal, the body o ring acts as your stationary seal face and the shaft sleeve is your rotating seal face. When sticky or abrasive product gets in the o-ring groove, it can cause the body o-ring to rotate, essentially grinding any product that gets under the o ring into the body o-ring groove, causing wear.
When we see this, we typically recommend a new or remanufactured pump. In this case, however, the customer already had a new pump coming and just need to limp by until it was installed. So what did we recommend? A little-known seal option- the lip seal.
The lip seal configuration is essentially a u-cup design. An o-ring is round and in a standard o-ring seal, any time we get a flat spot or wear on the body o-ring, product is going to push past the o-ring at the wear point or flat spot and leak. The u-cup uses a leading edge that creates a tighter seal against the shaft sleeve making it harder for product to leak past. In this lip balm application, it essentially filled the groove on the pump body. After installing the lip seals, it became immediately clear that this was the way to go. The pump sealed and ran just fine. When you know, you know.
Now there’s a reason why this is a “hack” and not a standard seal offering. The lip seal is a u-cup design that is very difficult to clean, almost impossible to CIP. The lip seal has similar pressure ratings to an o-ring seal and is not nearly as robust as a mechanical seal. And if you have body wear, it’s like a band aid on a bullet wound. We only recommended it for this application because they have new equipment coming and just had to limp along until it was commissioned.
That being said, if you’re running a chemical or highly abrasive product and want to stick with the simplicity of a o-ring type seal, or if your pump body is on it’s last legs and you just need to eek out a few more runs, the leading sealing edge created by the lip seal may be just what you need. If you have any questions about this lip seal or any of Waukesha’s Universal Pump Seal offerings, contact a Triplex Sales Engineer today!