Replacing EPDM rubbers with Viton in Grundfos UPS 25-62 180. 1

[freeland90]

Hello guys. I've asked this question about a previous pump I had, but it was not good for the job. I'm going to purchase Grundfos UPS 25-62 180, after consulting with the company which manufactures the coolant I'm going to use. They recommended changing all EPDM rubbers in this pump with Viton, as this coolant will cause EPDM to swell and leak (the coolant is expensive!) How can I determine the size of the gasket and o-ring in this model?

 

[3DDave]

The o-rings are likely to be a standard size any gasketing will have to be custom cut. You may only be able to get a gasket that fits from the maker; they may have that as an option.

 

[Artisi]

Have you ever thought of asking the manufacturer as it will also include the mechanical seal.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[freeland90]

Hello.
I've asked the manufacturer, looked at their spare parts (they only list gasket no sizes), I even asked a store speazlied in making gasket and o-rings, no luck with all.

However, In their datasheet, the dimensions are as follows:

Can you guys help me figure out the circular dimensions, the gasket rests just behind it. I thought I'd take B2 and double it: 514x2= 1038mm. Reasonable?

 

[TugboatEng]

Can you let us know the coolant you are running? Many engineers or... salespeople will specify Viton as a panacea but if your coolant is water based EPDM will likely provide the best life. If you're using an "oil" based coolant than you'll certainly need to make the change.

If you do need to make the changes, order the parts new from the manufacturer (they won't be very expensive for a pump this size) and use the new parts to make measurements or send to your local gasket supplier to cut gaskets.

If you're in USA, I have a local shop that will make a CAD drawing of your gasket for $25-50 and then can cut as many as you need for a low price.

You can also substitute anaerobic sealants and gasket tapes for cut gaskets.

 

[freeland90]

Hi Tug, The coolant Bitcool, it's definitely not water-based. These changes are a must. I think it's safe what you said. Thanks

 

[TugboatEng]

The SDS is very vague but due to its slightly flammable nature, no oral toxicity, and low conductivity I would guess the coolant is undiluted propylene glycol in which case EPDM would be ideal. Viton is equally suitable.

 

[freeland90]

Tug, EPDM is listed as not recommended for this Bitcool. Was the drawing helpful to determine the size?

 

[Artisi]

Was the drawing helpfull.... No!
What elastomer is in the mechanical seal?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Rputvin]

I'm fairly certain there are no mechanical seals in that pump, it's a contained rotor that's directly cooled by the fluid.

Bitcool is a dielectric fluid closer to mineral oil vs. glycol. We supplied a butterfly valve as part of a Bitcool project and had the correct viton everywhere but this one EPDM valve. The seats swelled and the butterfly was inoperable.

I haven't used the smaller UP/UPS pumps with Bitcool, the scale of our projects is usually 15-50hp pumps in this application. Make sure you get corrected curves from Grundfos, I'm fairly certain they have the fluid properties.

Edit:
Here's a PDF that contains a section view and BOM for the pumps. EPDM appears in the main gaskets, thrust bearing retainer, and the ball of the non-return valve. Section views are on sheets 11-13 of the document.

https://api.grundfos.com/literature/Grundfosliterature-5564731.pdf

Engineered Fluids told you to use this pump with Bitcool? Not the Magna3 magdrive series from Grundfos? I think the Magna lineup has less stuff in the wetted path and would have fewer items that need addressing.

 

[3DDave]

I followed the bread-crumb trail; Engineered Fluids had a blog post where they suggest a different line of pumps, ones with stainless housings and Viton seals. I expect the additional cost was what freeland was avoiding.

 

[Artisi]

Rputvin, you are correct, a seal-less can style pump.

Freeland 90,don't understand why you keep asking pointless questions here, we are not the manufacturer - how can you expect us to answer things we don't have information on. Why not simply dismantle the unit and get someone with a few brains to make a gasket from what ever you think is the appropriate material, it's certainly not rocket science.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[freeland90]

Thank you all for your answers. Artisis, you've been insulting me for a while. I'm sure my stupid questions can be ignored if you don't like'em.

 

[Artisi]

freeland90, I'm not being insulting just direct - the amount of time you have sent on this very very basic application would have been better served in contacting a respectable pump company - ie., Grundfos and asking for their recommendation. It would probably take a company pump application engineer 2 or 3 minutes to make a correct selection for your application.

The members of Eng-Tips answer questions out of the goodness of their heart , we are not mind readers nor do we get paid for doing it, but do appreciate some constructive input when we respond.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)