Pump modification for mechanical seal

For clear water handling pump the Mechanical seal required is a simple one- without the need to flush or cool etc.

For conversion to seal from packing - you will need to procure a seal housing from the manufacturer of the pump.

For oredring seal you will need to provide the following data to seal manufacturer or his dealer :

Shaft OD on which the seal will be mounted ( mm or in inches)

ID of the seal housing

length of seal housing bore

Standard seal surface - Carbon vs ceramic or Carbon vs SS will do unless the water is dirty in which case you can opt SiC vs TC or SiC vs SiC ( silicon carbide,Tunsten carbide).Unbalanced single seal is sufficient.

An experienced user usually can modify a stuffing box ( design permittiong) to accomodate a mech seal.

It depends where (in which country ) you are located.There are many local seal mannufacturers who can easily meet your requirement.List of manufacturers worldwide may run into pages!

Chuck Cowlagi

It is perfectly possible to use the mech face seal and retro-fit in the pump.

Get a reputed sel manufacturer from area to suit the seal to your application. he has to consider the pressure, surface speed, available area etc.

Since it is one off case, the costs of design may be high unless it is available off the shalf. Check the economics of the replacement.

check a site which almost answers your requirement.

http://www.mechanicalseals.net/

What is the exact problem that you are facing with the packing glands ? check whether that problem can be solved at a cheaper cost or not. Else go for the face-seals.

Pl remember that none of the seals are cure all, each have their specific area of applications

I am more concerned about the dimensions of the mechanical seal i.e can we get a mechanical seal that fits into seal housing bore and length.

Another point is the action to be taken first selection of mechanical seal then modifying the pump to suit the new seal

or design of new mechanical seal to fit in the same pump?

Do not try to design the seal unless you are an expert (we regularly use mech face seals in our equipment - not repeat not designed by us. We specify parameters, operating conditions and other things like dimensions etc and then the R&D wing/ institutions or the vendors design it for us.

As far as I know, there are vendors- standard vendors that is - who will be to fit a regular standard mech face seal into your pump (most probably but can not guarantee) and may require a minor modification (eg putting a housing to adjust the OD or putting a sleeve on shaft to adjust ID)

Just a cuation - after 25 years we thought we know all about it (and through studies) and tried to design a seal ourselves without the experts help- well as expected it failed a couple of times- struggled a lot again went thru all the literatures, designs, web and so on - till we could pipoint where we went wrong and re-designed the whole -( except size) - the loading on the seal face etc were all modifird. So unless you are expert/ have experts around, leave it to professionals.

Well in the long talk i didn't answer your point clearly

Based on the operating parameters - fluid, temperature, pressure, surface speed (rpm) , diameters, cavity available (ie the gap between the stationary hsg and shaft- length, diametrical gap etc) ) etc, select a standard mech face seal.

- This seal may just fit into your component. Most probable esp if the pump is standard size.

- May be adapted to fit into the component (say by putting in a hsg to adjust for OD or a sleeve for adjusting into shaft) - you may do it at your cost- may be cheaper.

- It is perfectly possible that the seal manufacturer will adapt the sleeve to suit you - most of the cases pump shaft dia will be standard size available with him, he will just change the OD of the seal to suit your hsg bore- which also is most likely a standard size - at a cost.

- Last option is the modification of the pump by machining the hssg bore- too much of effort and not recommended.

You will work in tandem - assume the seal is available and search and if not availableor a nearby one is available at a much cheaper price with same parameters then go for minor modifications as in step 2 or 3.

The problem you mention is a very common problem in many industries. I worked as a maintenance mechanic in the chemical industry for 35 years. No , I'm not an engineer, just a regular maintenance man.

New government regulations, and other environmental concerns are demanding that sealing water on regular stuffing boxes be reduced as much as possible, and converted eventually to mechanical seals. Most of the liquids that we dealt with was phosphoric acid in various strenghts.

Over the last few years, working with different vendors, my company has sucessfully converted almost all stuffing box/packing gland setups to mechanical seals. These setups use very little lube water. Some of the setups use a recirculating system, using the same lube water over and over. In most all centrifugal pump setups, our company was able to convert to some kind of mechanical seal. In other large pumps, the engineers were able to reduce seal water usuage with better packings, such as kevlar, and use seal water flow controls, trying to lower usuage to under 10 gallons a minute on a large pump.

My company also has a contract with the local municipality, to use gray water as much as possible. They were required to stop putting it in the local lake, their usual way, and we were required to use less fresh water, a usual several million gallons a day. The state regulation, and environmental officials loved the arrangement. the gray water is filtered as best they can, but it causes mucho buildup in the supply lines.

Sorry to be so long winded, but the concerns you mention are a common problem in many chemical industries. Hope I helped you.

Due to its softness, indium is considered an ideal material to create a compression seal in cryogenic applications, vacuum pumps, and in heat-sensitive areas.
Han Billion Metals and Chemicals Co., Ltd (http://www.hanbillion.com) supplies indium preforms in various shapes including flat washers, "O" rings, discs and rectangles. Foil and wire are available for custom seal fabrications.
Please feel free to contact us for more details and pricing.