We have a 25hp Travaini LRVP that has become a bit of a bear to fix. It started generating a rattling noise once the oil heats up and at certain vacuum pressures. When dead headed, the rattling dissipates. After speaking to Travaini US, they suggested that we replace the bearings on the pump. We did and the noise remained. We then thought that perhaps after many years of operation in a wood shop that the heat exchanger / radiator had become restricted due to build up. We replaced it with new, yet the rattling remained. We then changed the nose bearing (the bearing that sets the vanes to center in the pump housing) to a standard bearing that has a tighter tolerance than the C3. Our thoughts were that the C3 would allow for too much lateral movement. We checked the side to side clearance and found it to be in spec with the manufacturers specifications. The rattling remains. Include also, the mechanical seals were changed at bearing replacement and an oil change with the Travaini brand. This has become a major mystery. There just is not a lot of moving parts in this machine yet eliminating the noise is beyond perplexing. Has anyone else had this same problem?

How many hours are on it? Is there a valve or check valve that that can be rattling?

There is 20,000 + hours. There is a flat valve that is mounted at both ends of the pump. I'm not totally clear as to their purpose. They are mounted to a port that connects the center of the pump to a secondary cavity where the mechanical seals are located. I'm pretty sure this secondary chamber is just for keeping oil on the mechanical seals. I have attached a drawing and parts list of the pump.

Click the link below to download the file included with this post.

TRSC100.pdf


Click the link below to download the file included with this post.

Parts.pdf

Just generally speaking when someone says a rotary device is "grinding" in think bearings; when someone says it has a "rattling" noise I think wayward screw or nut.

When you replaced components as described above did you get into all the hidden chambers on the pump to make sure nothing had come loose to cause the rattling?

BH

May be worth exploring?

https://modernpumpingtoday.com/detecting-pump-cavitation/

Mark

Since some related parts were changed while it still does not work. In my opinion, it might be mechanical problems that caused this.

Thanks for all the replies. After speaking to a pump rebuilder, he said that on the steal pumps the port plate will wear after time. That wear increases the distance between the impeller and the port plate. If it wears enough, the service fluid seal opens up and allows air around the impeller. I guess it is similar to cavitation. We are sending it out for a rebuild. He did mention that the stainless pumps last about five times as long. At one time we cut a lot of MDF and we do from time to time cut Extira Board. I can't help thinking that those materials inevitably get in the oil as small particles and work as an abrasive. It seems as though we should create a secondary loop out of the reservoir with a small pump and filter that would remove some of those particles from the oil. I guess its not all that bad when you think we have had the pump for twenty years.