Hydraulic and pneumatic cylinders use O-rings and variations of O-rings without problems so do thousands of radial and liner actuators and valves as well.

If your cylinder bore is smooth and the O-ring material is compatible with the fluid being pumped I would think it would not be much of a problem.

Whats the worst that happens? It starts leaking again.

hello dear,

your comment is excellent.but take trial the life time of the ring. if it works ok then why u use oil seal.

Oil seals are better but provided they are designed for the axial movements. Most are for rotary sealing. The O rings or glands I have seen working better for this types.

O-rings used by themselves are ideal for static sealing where the sealing faces do not move in relation to one another.Dynamic sealing moved to profiles offfering less leakage ,higher wear charateristics and greater extrusion resistance. Based on the fluid, the speed and pressures you require, a range of seals may work for you giving you less leakage. However if your sealing surfaces have been scratched it is likely that whatever seal you replace it with will at some point leak as this scratch may allow bypass arond the seal. The surface finish of the sealing surfaces greatly effect seal life and performance. If the scratch was caused by metal to metal contact there may be wear and misalignment, or inadequate clearances and bearing surfaces, both of which may damage the seal, or the scratch may be caused my contaminated within your system again causing seal failures. However if the pump is non critical and easily accessible an o-ring may suffice ( but expect some leakage) , but i expect will need to be replaced more frequently.

if the pump manfacturer could of gotten away with using an o-ring they would have!

as you mention above, o ring is very ideal with static seal..so right now i used this o ring for seal the moving equipment because of the bad leak by using the original plunger seal. my question is what happen, if this seal for static equipment but we used for moving equipment?side effect for the or whatever?

O-ring should work for a short perod, but will be subject to more wear and leakage in the long run. but as above if the sealing surfaces are scratched you are still left with a route for the pressure/fluid to bypass any seal. its down to cost the ideal solution would be to remove the scratch and replace the seal with the original profile. in removing the scratch you will change the seal groove/ bore dimensions , most lip seals will cope with a small change in the radial cross section (the manufacturer should know) or you will need to get one machined to size. but with all seals what looks the same does not always work the same. go to a well known seal distrubtor for advice. The method of manufacture , seal profile and material all play key parts in its performance.

If it is possible to fit it in the the available space, a stuffing box and packing gives good service and long life in almost any conditions.

Other types of seal usually have less friction.

If the O ring works, replacement is easy and the consequences of having your pump down to do the replacement are not serious, use the O ring. It is cheap and shouldn't have any undesirable side effects.

any suggestion to replace my plunger pump?

now I already have 8 plunger pump that transfer chemical into the boiler...but its maintenance very frequently and costly to us..especially to replace the packing or seal...so hopefully, all of you can propose to me the type of pump that did not give troublesome to me just like this pump...their requirement
FREQUENCY 50/60Hz
MAX CAPACITY 0.35/0.42 L/min
MAX DISCHARGE 10MPa
SPEED 81/97 strokes per minute

Your pump specification @0.35 lpm is too low. I would have proposed to look for gear pumps, which can easily pick up the 100 bar that you need.

Are you sure it is only 0.35 lpm?

100 bar is max discharge...actually we need only 50bar... for the 0.35-0.42 lpm..confirm