Note: Descriptions are shown in the official language in which they were submitted.
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BACK~ROU~D OF THE INNENTION
The present invention relates to a device to
facilitate the servicing of oil well rod pumps.
~ conventional oil well pump used in pumping oil Erom
an operating well consists primarily of a horizontal main beam
or shaft which pivots in the cen-ter (like a teeter totter) with
one end of the main beam being driven up and down by a motor.
The other end of the main beam, or "head", has attached to it a
steel rod known as a "polish rod" which is moved up and down in
the valve mechanism of the oil well by the head of the main
beam moving -through an arc of approximately lO feet on each
recipLocation of the main beam.
~t its lower end, the polish rod is restrained from
movin~ too deeply into the well head by a collar-type clamp.
A-t its upper end, the polish rod is attached to the head of the
main beam by a hinged, U-shaped bridle and by a second clamp.
The bridle allows the polish rod to constantly remain in a
vertical position while it is moved up and down in the oil well
valve mechanism.
In order to service the bridle, rod or motor powering
the beam, it is essential that the weight of the rod string be
supported. Conventionally, it is supported by moving -the
clamps on the bridle and -the lower end of the polish rod so
that the lower clamp ultimately rests on the oil well valve,
thereby supporting the entire weight of the rod strin~. This
creates problems since the surface oE the polish rod must be
kept extremely smooth because of the manufacturing -tolerances
between the eolish rod and the oil well valve through which it
reciprocates. The movement of the clamps and the necessity of
securing them tightly against this smooth, lubricated surface
of ths polish Lod in order to bear the entire weight of the rod
string inevitably causes scarring and deformation of the polish
rod surface. This action in turn rapidly damages the oil well
valve mechanism and its packing, requiring frequent replacement
thereof. An additional problem with using such clamps to hold
the weigbt of the rod string of the oil well pump is that the
clamps may slip, allowing -the polish rod to fall into the oil
well valve mechanism, causing both damage to the oil well valve
mechanism and a substantial safety problem for servicing
personnel.
Canadian Patent No. gO0,843 of Lodynski issued May 23,
197Z, of general background interest, describes and illustrates
an hydraulic cylinder apparatus which is attached to the polish
rod of an oil well pump to permit controlled movement of that
rod and assist in setting the suspension means of a deep well
pump ins-tallation during operation. Canadian Patent No.
530,257 describes and illustra-tes a polish rod clamp and
Canadian Patent No. 995,131 describes and illustrates a cable
device to remove parts from a polish rod.
It is an object of the present invention to provide a
device which may be used in servicing such an oil well pump
ulrem~lt. ~ undoin~ and relocating
clamps on the polish rod to permit servicing to take place.
SUMMARY OF THE INVENTION
In accordance with the present invention there is
provided a device Eor use in servicing an oil well rod pump.
The pump has a rod string with a rod clamp secured thereto
above the polish rod. The device compr;ses an elongated,
weight-supporting polish rod-receiving cylindrical sleeve. The
inner diameter of the sleeve is greater than the diameter of
the polish rod. A slot in the side o~ the sleeve extends along
its length. The width of the slot is slightly greater than the
diameter of the polish rod. A ~lange e~tends outwardly from
each side o~ the slot. Releasable securing means extend
between the flanges to secuee the sleeve in position about the
polish rod. The sleeve is to receive. resting thereon when in
position about the polish rod, the rod clamp to permit
servicing work on equipmen-t such as -the bridle, main shaft,
head or motor, above the rod clamp.
In a preferred embodiment of the present invention a
cap, which is provided at the end of each sleeve, has a central
circular rod-receiving hole and, communicating therewith, a
rod-receiving slot coincident wi-th that of the sleeve.
It ~ill be unders-tood tha~, in using a device in
accordance with the preserlt invention, the various rod clamps
J ~r~
do no-t need -to be moved to service the various par~s of the
equipment, thereby avoiding the type of damage to the polish
rod which had occurred previously, when moving the rod clamps
to service the equipment. The use of the device according to
the present invention also forestalls the possibility of the
polish rod and the valves to which it is attached being droeped
into the inground portion of the oil well as would occur for
example if both rod clamps were to slip while being moved.
Because use of the device according to the present invention
10 minimizes scarring of polish rods, i-t leads to decreased
stuffing box eacking wear. There is also a substantial saving
of time in the servicing of each well, which allows ~he well ~o
be back in production quickly, in using the device according to
the present invention.
~RIEF D~SCRIPTION OF TH~ DRAWINGS
These and other objects and advantages of the
invention will become apparent upon reading the following
detailed description and upon referring -to the drawings in
which:
FIGURE 1 is a perspective view of a device in
accordance with the presen-t invention; and
F'IGURE 2 is a schematic elevation view of the head
portion of an oil well rod pump, to a portion of which the
device of FIGURE 1 has been fitted, to illustrate -the manner of
use of that device.
While the invention will be described in conjunction
with an example embodiment, it will be understood that it is
not intended to limit the invention to such embodimen-t. On -the
con-trary, it is intended to cover all alternatives,
modifications and equivalents as may be included within the
spirit and scope of the invention as defined by the appended
claims.
DETAILED DESCRIPTION OF THE INVENTION
In the drawings similar features have been given
similar reference numerals.
Turnin~ to the drawings, there is illustrated in
FIG~RE 1 a rod saver device 2 in accordance with the present
invention, the device comprising a sleeve 4 adap-ted to carry
fairly significant weights. The sleeve is of elongated,
cylindrical construction and has an inner diameter which is
greater than the diameteL of the ~olish rod 6 (FIGURE 2) about
which it is to fit. An elongated slot 8 extends along the
length of sleeve 4 in its side, the width of the slot being
slightly greater than the diameter oE polish rod 6. A pair of
confronting flanges lO extend outwardly, as illustrated, from
each side of slot 8. Pins 12 are releasably securable, as
4 ~
illustLated, through aligned holes 14 in flanges 10 -to hold
device 2 in position on eolish rod 6 when in use.
To the ends of sleeve ~ are secured end caps 16, each
of the caps having a central circular, polish ro-l-receiving
hole 18 and a slot 20 communicating therewith, slot 20 having a
width similar to that of slot ~ and being aligned therewith.
In this manner, device 2 can be pushed into place
around polish rod 6 and secured by pins 12.
As seen in FIGURE 2, rod string 22, of which polish
10 rod 6 is a portion, is suspended from and driven by the head 24
at the f ront of main beam 26 of the oil well pump. This is
accomplished by means of carrier bar 28, secured to head 24 by
means oE rods 30. The weight of rod s-tring 22 is on carrier
bar 28. Upper rod clamp 32 and lower rod clamp 34 secure rod
15 string 22 to carrier bar 28 and prevent the possibility of
polish rod 6 being dropped into the inground portion of an oil
well when secured in eosition. Rod string 22, at polish rod
portion 6, extends into the oil well through stuffing box 36.
~s previously in~icated, -to service oil well pump
20 equipment located above lower rod clamp 34, lower rod clamp 34
previously had to be undone and moved down -the polish rod to a
position immediately above stuffing box 36 where it would be
resecured. The Lod string 22 would then be lowered until this
clamp 34 was resting on stuffing box 36 and service work above
25 clamp 34 then carried out. When the service work was
f ~
eompleted, lower rod clamp 34 would -~hen be reeosi-tioned at its
original position.
When a device 2 is used in aceordance with the present
invention, polish rod 6 is inserted into sleeve 4 between clamp
3~ and stuffing box 36. Rod string 22 is then lowered until
clamp 34 rests on the ueper cap 16 of sleeve 4. In this
manner, the rod string weight iB on device 2. Servicing may
then be carried on above clamp 34 in the usual manner. ~s
well, as ereviously stated, use of the deviee aecording to the
eresent invention has significantly reduced stuffing box
paeking wear which previously oceurred because of scarred
polish rods.
Because, in using the device according to the present
invention, it is no longer necessary to unclamp and reposition
lower rod clamp 34 on polish rod 6, and then reposi~ion it
after servicing of the pume equipment, scarring of the working
part o~ eolish rod 6 due to clameing is avoided. ~s well,
where the rod string 22 must be unelameed so that it is no
longer sueported by carrier bar 28, since lower rod clamp 34
remains clamped in position, the likelihood of clamp 34
slipping to allow the eolish rod 6 to fall into the oil well
valve mechanism is significantly reduced. ~-t the same time,
the task of readying an oil well pump for servicing is greatly
simplified and the time for so doing is greatly ~educed.
Thus it is apparent that there has been erovided in
accordance with the invention a servicing device for oil well
rod eumps that fully satisfies the objects, aims and advan-tages
set forth above. While the invention has been described in
conjunction with a specific embodiment thereof, it is evident
that many alternatives, modiEications and variations will be
apparent to those skilled in the ar-t in light of the Eoregoing
descLiption. Acco~dingly, it is intended to embrace all such
alternatives, modifications and variations as fall within the
spirit and broad scope of the invention.
