Reciprocating Packing & Dampener Problem 1

[symd]

Hello Everyone,

Appreciate your advise, input and experince on following problem which I am facing for the past few months.

We have two triplex plunger pumps that repeatedly fails. We experiencing plunger packing leak, dampener broken and required frequent shutdown, max 2 weeks.

We monitor the dampener (Flowguard). It seem that the pressure is decreasing and later failed due to in adequate pre-charge. We believe there is some kind of loose connection while pump is running.

The plunger packing also frequently leak. It need change every 3 - 5 wk. Packing is made from braided peak.

I don't know how is this relate but if dampener working well, the packing is ok. Once the dampener broke, the packing will follow.

Pump is serving glcyol (TEG) at 80 barA & 140 deg Cel.

Appreciate if you guys can tell me what is happening, what need to be change, what type of packing is suitable, what type of bladder is suitable since we have keep changing this parts for every months.

 

[unclesyd]

There is a lot of missing information in your post concerning the piston size, the piston material, packing style and design, how is it failing, the pump arraignment and so on.
Come back with more details if possible.

Immediate steps would be to talk with Flowguard about diaphragm material compatibility with the process fluid and if your dampener is the proper size for the application.

 

[symd]

Thanks Unclesyd

Info required:
1. the piston size is (Bore x stroke) 2.1/2" to 2.1/4" x 3.1/2" ,

2. the piston material is Tunsten Carbide coated SS,

3. packing style and design is normal type 4 pcs per plunger. Not a V type

Pump is running 24hr x 7d - non stop. Scenario of damperner failure as I mentioned earlier, pressure decrease then burst. if we maintain pre-charge pressure by weekly charging, damperner will last.

For packing, first we can see an increase drop of glycol leak. After a while (day or two) this drop will get worst and we can see fluid folwing out from stuffing box.

Last week we also observe pitting at plunger while changing the packing.

Thanks

 

[symd]

FLowguard was contacted but they said the membrane is ok.

I agree the membrane is ok but what is the reason of pressure decrease and why the packing leak so frequent.

 

[symd]

Sorry i miss your question, the membrane is Viton. Do you have similar application for glycol working at 140 deg Cel and 80-85 barG.

If you do, what type of packing and membrane you are using. I will use same one as try-an-error.

 

[stanier]

If this a bladder type of pulsatin dampener usually there is anitrogen source that maintains the pressure on top of the bladder. The one changes the bottle over when the pressure in the bottle regulator begins to fall. If this happens regularly then there is a leak in the tubing between bottle, regulator and accumulator.

If the accumulator is undersized then the bladder may be exhausting gas regularly and emptying the bottle.

 

[unclesyd]

We never had much luck with tungsten carbide coated piston rods on any pumping system.
I personally haven't like to use stainless steel as a plunger material. If we used SS it was material like 17/4 or 420 and most of the time it was hard chrome plated or nitrided if the process would allow it.

Is the WC2 flaking off or is it a true corrosion pit?
Have you checked the whole shaft for TIR?
Are there any micro-cracks in WC2?

 

[svanels]

When the bladder fails, the packing will follow. Do you have a pressure gauge on the discharge of the pump? An oscilating needle is the first sign of bladder malfunction. Also check for leaks at the nitrogen filling system. Place a permanent gauge to check the nitrogen pressure.

 

[RMNKBR]

I'd appreciate comments of plunger (triplex) pump packing in gasoline service (100°F, Ps= 30 psig, Pd= 665 psig, 185 RPM).

Pump model is Wheatley HP100L. Packing needs replacement from 10 to 30 days. We're using Zero emission packing sets that are Tandem Sets (2 sets of packing that create a barrier between them to capture trace emissions).

Selection of packing looks right to me so plan is to confirm all dimensions are OEM to eliminate plunger or stuffing box problems. There is only damper in the Discharge line. There is no damper in the suction line but not sure how it may affect.

I'd appreciate your comments and ideas. Thanks.

 

[unclesyd]

RMNKBR,

It would pay you to start a new thread and red flag this post.

You will get much more response to your post by doing this.

PS
You scared me to start with as the few Wheatley pumps That I've been acquainted with were water pumps.

 

[RGRAJANI]

I am facing similar problems for similar service.

Can "symd" update the actions taken for reliability improvement ?

 

[btrueblood]

140 C Glycol - any water in the glycol? If so, then Viton is the wrong material. Not sure what the "right" material would be, but I know that Viton can suffer hydrolysis attack from high temperature water.

 

[RGRAJANI]

btrueblood,

TEG @ 85 Deg C, Disc. pr. 120 Bar. Failure is not chemical attack on rubber, but lose of pressure loss over few days / weeks. Also packing life is few weeks only.

 

[symd]

RGRAJANI

We change bladder to free maintenance type.

 

[RGRAJANI]

symd

Can you please elaborate "free maintenance type" ?

We are thinking to implemet preventive packing adjustment every month and replacement every 3 month. What is your experience ?

Thanks for reply.

 

[symd]

RGRAJANI

damperner mfr is Performance Pulsation Control. Instead of bladder type, it is fully mechanical internal design creating some kind of flow that reduce damperning effect.

Please search website for details

If you do not have a problem with damperner, why dont you try different type of packing. It is cheap and worth trying. You may start with teflon which is proven for min 3 months. Do not buy from pump manufacturer but direct from packing manufacturer. It will cost less than US10 per pcs.

by the way, what brand you pump is?. We have another pump serving condensate, brand is WEPUKO. no problem for past 1.5yrs, since commissioned. Very queit. SO for all new pumps, we go by WEPUKO as much as we can.