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Rod Knuckle Stuffing Box Servicing Procedures
1.
On a conventional pump jack shut the jack down so the horse’s head is at the top of the
stroke. This will insure there is adequate room for the Rod Knuckle to be pushed up the rod
when servicing the Rod Knuckle. This will also allow you to visually inspect the bottom
portion of the polished rod.
2.
As illustrated below, shut in the Radigans on the well to seal the wellhead pressure
from the Rod Knuckle.
3.
Shut in the tubing valve and bleed the pressure off of the Rod Knuckle. If the radigans
are not holding, servicing the Rod Knuckle can not be done safely and servicing the wellhead
is recommended before proceeding.
4.
Bleed off the pressure inside of the Rod Knuckle using the ½ inch ball valve (part
RK783-013) equipped on one side of the Rod Knuckle.
The Rod Knuckle comes equipped with a pressure valve (part RK7883-014 which will
enable you to see how much pressure, if any, is inside the Rod Knuckle). NOTE: There should
be no pressure in the middle chamber to maintain proper operation of the Rod Knuckle. The
upper packing is meant to be a back up should the lower packing wear out; properly
maintaining the upper packing is just as essential as the lower packing.
5.
Once all the pressure is safely bled off the Rod Knuckle, loosen both top and bottom
safety thumbscrews (shown below on the right hand picture). Take the upper packing gland
off (left hand picture) and slide the top packing gland (part RK7883-027 or -028) up the polish
rod so the upper packing and top split ring packing retainer (part RK7883-005 or -006) can be
inspected. Use a spanner wrench for easy handling and to eliminate marking the Rod Knuckle.
6.
After taking the upper packing out inspect the top split rings. This can be easily be done
by taking the ¼ inch ready rod or by unscrewing the bottom section of your packing pullers
and thread it into the top section of the split ring packing retainer. This should be inspected for
side load or any damage. This will be a good indicator if the well is in good aliment or not;
replace if wear is evident. The brass split rings were designed to contain the packing and not
score the polished rod. If they show signs of wear there is likely an alignment problem and the
packing retainer will not hold the packing as designed so your packing will wear out than faster
normal. (As seen in below pictures)
7.
After Inspection is done DO NOT replace the top packing and brass split ring until last
as this will allow you relief if there is side loading on the lower packing. To inspect the check
valve (part RK7883-020, -021 or -022) loosen the set screw located in the Knuckle Nut (part
RK7883-026); you will need an Allan wrench 20 or ¼ inch. Once that is done use a strap
wrench to loosen the Knuckle Nut (see picture below).
8.
Slide all loose components up the polished rod and clamp at a safe height. Ensure the
clamping devise will not score the polish rod.
9.
It is recommended practice to inspect the check valve for wear and damage every time
the packing is changed. Should the polished rod break the check valve has to be in good
condition to do its job. The picture below shows what can happen when the polished rod gets
too hot (i.e. the pumping system is not pumping fluid as it should; a fluid level and
dynamometer is recommended to find and fix the pumping problem). The check valves should
never break down as seen below, this is a symptom of a larger problem and is a good indicator
that the pumping system should be tested.
10.
To install a new check valve you will need to loosen the bottom portion of the Rod
Knuckle (Control Chamber RK7883-018 from the flowtee adaptor) to gain easier access to the
check valve. Loosen the control chamber in a left handed motion and tilt the control chamber
until the check valve is accessible; if necessary replace with a new one. Slide floating check
valve seat (RK7883-019), the bottom bronze ring (RK7883-023), the knuckle (RK7883-025),
the top bronze (RK7883-024) and the knuckle nut (RK7883-026) back on to the control
chamber (RK7883-018) and tighten. Once it is tightened ensure that the set screw is tightened
back-up. Slide the Rod Knuckle up the polish rod again to a safe height and clamp securely as
shown below.
11.
Inspect the lower packing gland ring and split ring (RK7883-009A or 009B and
RK7883-010A or 010B), if damaged this is also an indicator of well misalignment. If the lower
packing gland split ring needs to be replaced, remove the two sets screws from the lower
packing gland ring to disconnect the two pieces. Pull the lower packing gland split ring apart,
remove from the polished rod and replace with a new one. Retighten set screws ensuring not to
over tighten which will cause stress to the split rings.
12.
After taking the lower primary packing out inspect the Lower Packing Gland split
rings. This can be easily be done by taking the ¼ inch ready rod or by unscrewing the bottom
section of your packing pullers and thread it into the top section of the split ring packing
retainer. This should be inspected for side load or any damage. This will be a good indicator if
the well is in good aliment or not; replace if wear is evident; this is where you will see the most
wear from side load or alignment problems. The brass split rings were designed to contain the
packing and not score the polished rod. If they show signs of wear there is an alignment
problem and the packing retainer will not hold the packing as designed so your packing will
wear out than faster normal. (As seen in below pictures). If misalignment is serious problem
you may have to take the flow tee adaptor out of the well to retrieve and service the bottom
split rings. Replace if needed and set bottom split ring packing retainers back into the bottom
of the flow tee adaptor and replace bottom packing with 4 rings of packing.
13.
After inserting the lower packing in the flow tee adaptor begin to pull down the rest of
the Rod Knuckle on top of the bottom packing gland. With brass spanner wrench, tighten the
bottom portion of the Rod Knuckle and tighten thumbscrew (finger tight) on control chamber
(RK7883-018). Please note; there are two indicator lines on the flow tee adaptor; the first
indicates that the packing gland is in contact with the top of the primary packing; the second
shows that the packing is worn out and needs replacing.
14.
Tighten the knuckle nut (RK7883-026) on to the control chamber and tighten set screw
if not already done in previous step.
15.
Install top Split Ring Packing Retainer and replace the upper packing. Using a spanner
wrench tighten the top Threaded Packing Gland (RK7883-027 or 028). Tighten thumbscrew
(finger tight)!
16.
Ensure all valves are closed on the Rod Knuckle. Slowly loosen the radigans to allow
pressure back onto the Rod Knuckle and crack open up tubing valve so the pressure can be sent
down the flow line.
17.
If pressure is evident in the Rod Knuckle tighten until seal is made. Fill oil chamber
with oil and stroke well until proper tightness is made. You may have to loosen or tighten
depending on the well and if there is pumping function right away or not.