Repairing Ball Valves

I don't know about the valves. I just thought you might want to change your username - syphilis is a spirochete. Do you want to be associated with a venerial disease?

Well He does want to put His Balls to the Grindstone.

A venerial disease is nothing to clap about.

Spirochete61 I have repaired many of these valves over the years. I would disassemble the body and replace the seals, I have never encountered a ball damaged on the sealing surface where it would matter. If I were to encounter a damaged ball I would replace the valve. Jerrell

I'am talking about 20" ball valve, in our resin or polymer line so possibly the resin have damage the ball. Yes replacement is a possibility but the cost is to much 1 valve cost $30,000 we have more than 20 of these so iam looking for any alternative method.

If the resin is attacking the valve, consider what it might be doing to the inside of the pipework......

Are the materials of construction of all the process lines correct?

Dear friend its easy to fix, ask a good machinest him can fix it

yes the damage occured before we change the seat. Before it was soft seated now it is metal seated. So the problem occured before so that was our corrective action. But as we know because of the recession were cost cutting right now so were trying to find cheaper ways...

Q1: So it isn't the resin; the seat is wearing away the ball. Is this correct?

Q1.5: what are the materials of construction of both ball and seat?

Q2: what is the make of the valve?

Q3: hand-operated or air/electric motor-operated?

Sounds like issues of quality and bottom line cost accounting created your problem in the first place.

Safety has become your major issue now, I hope your plant is not near My Friends or Myself.

Shimming will not change the radius of curvature, you have to get new seats with the curvature (of the ball) else you will land up in much reduced sealing surface.

In case of hard (or metal seated valves), you may also have to ensure precise profile matching by lapping etc along with the joint pressure (sorry not in the valve design field so do not have any idea bout the pressure maintained, however being on the user side, have the idea of requirements.)

Yes.

A long time ago and far far away....I was involved with PVC manufacturing using similar valves. These were 8, 10, 12 and 16 inch valves. I don't recall any 20 inch valves. If these are floating ball valves (not trunnion mounted balls) and a soft seat, I saw damage to the seating area and polymer buildup between the ball and the cavity or body of the valve. Not only is the seating when closed area subject to damage but the area between the opening and the "ring around the opening" subject to damage.

Many shops could do it wrong. There were a few (two I knew) shops that specialized grinding, electropolishing and re-chroming these balls that could do it right.

The difference was the shop's ability to measure and maintain "Spherosity (sp?)" of the balls. (That would be the question to ask the repair shop) My experience that there is no need to shim the seats. If the ball is spherical and the seat round, then the balls can be reground, electro-polished or chromed and returned to service. We were maintaining two and three piece body floating ball valves long after they were not manufactured or body styles changed. As you probably know, the floating ball needs a differential pressure to initially push the ball against the downstream seat. The smaller ball was thought to require a higher DP in a horizontal position to seat, but it was never proven.

One other comment is that the special anti-fouling juice applied to the wetted parts in the valve was not the same as what worked in the reactors. For reasons unknown to me, an older chemistry was DOEd and found to be different than best reactor stuff.

In a vertical up flow position i expect there may be significant additional DP to push the ball up and hold it against the upper seat.

Good luck and please respond back if you have success

Paddler

yes were having the ball re-chrome and the shops whose going to do it said the diameter will loose 1 mm thats why they need to put shim at the seat and body. Its already in process i'll update you what will happen.

But before we put in line it needs to pass on all my test. High pressure low pressure back seat etc.

Thanks for ur reply.

By the way the material for the seat is SUS 316 and the seat is SUS 316 also

A couple of questions I would be interested in is the polymer type, application and degree of shutoff required. We never achieved bubble tight shutoff in reactor discharge service. To prevent monomer from entering the valve and polymerizing in the annulus we put two in series, And pressured up the space between them with DI water flush. We watched the pressure to maintain higher than the reactor pressure and watched flow. When flow got too high the valves were cleaned/repaired or reworked. Probably easy to automate now, at the time it was rotameters, pressure gauges and round-sheet inspections.

I have a small valve repair shop and I would like to have some v-balls reworked can you e-mail me who you are using to do the rechroming. My e-mail is spud@hughes.net

Thanks

Spud

My question for you is what is the ball material made of? In my industry, we have a bundle of nylon balls in our gate valves that take a beating from debris in the water, so we see damage in the way of scoring on a linear manner from material caught in the seat surface between the ball and seal. Brass balls in the housings do okay for a while then they begin to go away. We insert stainless steel balls in the brass housings and with the nylon seals, we have more than doubled our life span on the gate valves. These are on fire engines that have been in service upwards of 15 years, before they begin failing.

I am under the impression that there may be a high temperature associated with your manufacturing process? How often have you had to make the repairs, and have you considered just rebuilding the valve by installing a kit that has all of the internal parts required?

For time and money associated with such a repair, I would recommend making the rapair using a kit.

Thats my 2cents. Good luck

If the cost of the ball is prohibitive, or not available, it should be possible to have the gouged section of the ball filled with plasma spray, or building it up with weld. Then it could be returned to original dimensions. Good luck.