CA2349988E - Polish rod locking clamp - Google Patents
Polish rod locking clamp Download PDFInfo
- Publication number
- CA2349988E CA2349988E CA002349988A CA2349988A CA2349988E CA 2349988 E CA2349988 E CA 2349988E CA 002349988 A CA002349988 A CA 002349988A CA 2349988 A CA2349988 A CA 2349988A CA 2349988 E CA2349988 E CA 2349988E
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- CA
- Canada
- Prior art keywords
- polished rod
- clamp
- bore
- pistons
- piston
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000009434 installation Methods 0.000 claims abstract description 33
- 239000003129 oil well Substances 0.000 claims abstract description 28
- 239000002184 metal Substances 0.000 claims description 44
- 239000012530 fluid Substances 0.000 claims description 15
- 238000007789 sealing Methods 0.000 claims description 7
- 238000000576 coating method Methods 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 230000013011 mating Effects 0.000 claims 3
- 239000011248 coating agent Substances 0.000 claims 2
- 238000012423 maintenance Methods 0.000 description 8
- 230000002250 progressing effect Effects 0.000 description 8
- 239000010779 crude oil Substances 0.000 description 4
- 239000003921 oil Substances 0.000 description 4
- 239000004576 sand Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
- E21B19/12—Rope clamps ; Rod, casings or tube clamps not secured to elevators
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
- E21B43/126—Adaptations of down-hole pump systems powered by drives outside the borehole, e.g. by a rotary or oscillating drive
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Jigs For Machine Tools (AREA)
- Actuator (AREA)
Abstract
A polished rod lock out clamp for use in securing the polished rod in an oil well installation, comprising a clamp body having a bore for receiving a polished rod in spaced relation to the bore; clamp members in the clamp body for engaging a polished rod in the bore; and radial bolts secured to the clamp body and the clamp members for moving the clamp members between a polished rod gripping position where the clamp members grippingly engage the polished rod to prevent rotation and axial movement thereof and a retracted position where the clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in the bore of the clamp body.
Description
POLISH ROD LOCKING CLAMP
FIELD OF THE INVENTION
The present invention relates generally to progressing cavity pump oil well installations and, more specifically, to a polished rod lock out clamp for use in progressing cavity pump oil well installations.
BACKGROUND OF THE INVENTION
Progressing cavity pump drives presently on the market have weaknesses with respect to the stuffing box maintenance. Oil producing companies need a pump drive which requires little or no maintenance, is very safe for operating personnel and minimizes the chances of product leakage and resultant environmental damage. When maintenance is required on the pump drive, it must be safe and very fast and easy to do.
Due the abrasive sand particles present in crude oil and poor alignment between the wellhead and stuffing box, leakage of crude oil from the stuffing box is common in some applications. This costs oil companies money in service time, down time and environmental clean up. It is especially a problem in heavy crude oil wells in which the oil is often produced from semi-consolidated sand formations since loose sand is readily transported to the stuffing box by the viscosity of the crude oil. Costs associated with stuffing box failures are one of the highest maintenance costs on many wells.
Servicing of stuffing boxes is time consuming and difficult. Existing stuffing boxes are mounted below the drive head. Stuffing boxes are typically separate from the drive and are mounted in a wellhead frame such that they can be serviced from below the drive head without removing it. This necessitates mounting the drive head higher, constrains the design and still means a difficult service job. Drive heads with integral stuffing boxes mounted on the bottom of the drive head have more recently entered the market. In order to service the stuffing box, the drive must be removed which necessitates using a rig with two winch lines, one to support the drive and the other to hold the polished rod. This is more expensive and makes servicing the stuffing box even more difficult. As a result, these stuffing boxes are typically exchanged in the field and the original stuffing box is sent back to a service shop for repair-still unsatisfactory.
Prior art blow out preventers, while similar in structure, are not intended to grip the polished rod in metal to metal contact to suspend a polished rod and prevent axial or angular displacement of the polished rod. The function of the narrow elastomeric seal as sometimes used on existing blow out preventers is only to seal between the pistons, between the pistons and the polished rod and between the pistons and the piston bores. The reason for using a narrow elastomeric seal is that this construction has enhanced sealing at high pressure compared to blow out preventer pistons that are predominantly elastomeric with steel inserts for engaging with the actuating means. Existing blow out preventers have the grooves in the pistons substantially filled with the elastomeric seal and at the piston face the elastomeric seal projects beyond the piston face. When the pistons are closed together the elastomeric seals cannot be pushed into the grooves since the grooves are already substantially filled by the elastomeric seal, Seal volume in prior art exceeds the volume of the grooves in the piston. Thus, metal to metal contact between the pistons and the polish rod cannot be achieved because the seals always project beyond the piston face. Contact between the polished rod and the elastomeric seal is not adequate to suspend the polished rod weight because of the shear stress limitations of the elastomer and the lower coefficient of friction between the elastomer and the polish rod in a wetted condition. Additionally, the enhanced gripping force that can be achieved by making the radius on the piston face smaller than the radius of the polished rod is substantial but cannot be achieved without metal to metal contact.
SUMMARY OF THE INVENTION
The present invention seeks to simplify the issue of stuffing box maintenance by eliminating the need to support a polish rod with a rig and winch line during such maintenance. In order to eliminate the need for a rig, the present invention provides a special clamp integrated with or below the drive head to support the polished rod and prevent rotation while the stuffing box is serviced. Blow out preventers can be integrated into the clamping means and are therefore closed while the stuffing box is serviced, thus preventing any well fluids from escaping while the stuffing box is open.
According to the present invention then, there is provided a polished rod lock out ciamp operable to suspend a polished rod in an oil well installation, comprising a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore;
and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in metal to metal contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
FIELD OF THE INVENTION
The present invention relates generally to progressing cavity pump oil well installations and, more specifically, to a polished rod lock out clamp for use in progressing cavity pump oil well installations.
BACKGROUND OF THE INVENTION
Progressing cavity pump drives presently on the market have weaknesses with respect to the stuffing box maintenance. Oil producing companies need a pump drive which requires little or no maintenance, is very safe for operating personnel and minimizes the chances of product leakage and resultant environmental damage. When maintenance is required on the pump drive, it must be safe and very fast and easy to do.
Due the abrasive sand particles present in crude oil and poor alignment between the wellhead and stuffing box, leakage of crude oil from the stuffing box is common in some applications. This costs oil companies money in service time, down time and environmental clean up. It is especially a problem in heavy crude oil wells in which the oil is often produced from semi-consolidated sand formations since loose sand is readily transported to the stuffing box by the viscosity of the crude oil. Costs associated with stuffing box failures are one of the highest maintenance costs on many wells.
Servicing of stuffing boxes is time consuming and difficult. Existing stuffing boxes are mounted below the drive head. Stuffing boxes are typically separate from the drive and are mounted in a wellhead frame such that they can be serviced from below the drive head without removing it. This necessitates mounting the drive head higher, constrains the design and still means a difficult service job. Drive heads with integral stuffing boxes mounted on the bottom of the drive head have more recently entered the market. In order to service the stuffing box, the drive must be removed which necessitates using a rig with two winch lines, one to support the drive and the other to hold the polished rod. This is more expensive and makes servicing the stuffing box even more difficult. As a result, these stuffing boxes are typically exchanged in the field and the original stuffing box is sent back to a service shop for repair-still unsatisfactory.
Prior art blow out preventers, while similar in structure, are not intended to grip the polished rod in metal to metal contact to suspend a polished rod and prevent axial or angular displacement of the polished rod. The function of the narrow elastomeric seal as sometimes used on existing blow out preventers is only to seal between the pistons, between the pistons and the polished rod and between the pistons and the piston bores. The reason for using a narrow elastomeric seal is that this construction has enhanced sealing at high pressure compared to blow out preventer pistons that are predominantly elastomeric with steel inserts for engaging with the actuating means. Existing blow out preventers have the grooves in the pistons substantially filled with the elastomeric seal and at the piston face the elastomeric seal projects beyond the piston face. When the pistons are closed together the elastomeric seals cannot be pushed into the grooves since the grooves are already substantially filled by the elastomeric seal, Seal volume in prior art exceeds the volume of the grooves in the piston. Thus, metal to metal contact between the pistons and the polish rod cannot be achieved because the seals always project beyond the piston face. Contact between the polished rod and the elastomeric seal is not adequate to suspend the polished rod weight because of the shear stress limitations of the elastomer and the lower coefficient of friction between the elastomer and the polish rod in a wetted condition. Additionally, the enhanced gripping force that can be achieved by making the radius on the piston face smaller than the radius of the polished rod is substantial but cannot be achieved without metal to metal contact.
SUMMARY OF THE INVENTION
The present invention seeks to simplify the issue of stuffing box maintenance by eliminating the need to support a polish rod with a rig and winch line during such maintenance. In order to eliminate the need for a rig, the present invention provides a special clamp integrated with or below the drive head to support the polished rod and prevent rotation while the stuffing box is serviced. Blow out preventers can be integrated into the clamping means and are therefore closed while the stuffing box is serviced, thus preventing any well fluids from escaping while the stuffing box is open.
According to the present invention then, there is provided a polished rod lock out ciamp operable to suspend a polished rod in an oil well installation, comprising a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore;
and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in metal to metal contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
According to another aspect of the present invention, there is provided a polished rod lock out clamp for use to temporarily suspend a polished rod in an oil well installation, comprising a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore; metal clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for metal to metal contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
In a still further embodiment of the present invention, there is provided a combined blow out preventer and polished rod lock out clamp for use in an oil well installation, comprising a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing; clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a metallic piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation; eiastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
In yet a further embodiment of the present invention, there is provided a polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore; clamp members in said clamp body having an elongated arcuate inner metallic surface for grippingly engaging the polished rod in metal to metal contact, each said clamp member being radially moveable with respect to the polished rod; and radially disposed bolts threaded into said clamp body for manipulation of said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod relative to said axial bore of said clamp body.
In still yet another embodiment of the present invention, there is provided a polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore; two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end to be semi-circular in cross-sectional shape for receiving and grippingly engaging said polished rod in metal to metal contact; radially disposed bolts threaded into said damp body for manipulation of said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body; and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping From the well bore, said elastomeric seals being compressible to aliow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
This and other features of preferred embodiments of the present invention will become more apparent from the following description in which reference is made to the appended drawings in which:
Figure 1 is a view of a progressing cavity pump oil well installation in an earth formation with a typical drive head, wellhead frame and stuffing box;
Figure 2 is a view similar to the upper end of Figure 1 but i{iustrating a conventional drive head with an integrated stuffing box extending from the bottom end of the drive head;
In a still further embodiment of the present invention, there is provided a combined blow out preventer and polished rod lock out clamp for use in an oil well installation, comprising a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing; clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a metallic piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation; eiastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
In yet a further embodiment of the present invention, there is provided a polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore; clamp members in said clamp body having an elongated arcuate inner metallic surface for grippingly engaging the polished rod in metal to metal contact, each said clamp member being radially moveable with respect to the polished rod; and radially disposed bolts threaded into said clamp body for manipulation of said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod relative to said axial bore of said clamp body.
In still yet another embodiment of the present invention, there is provided a polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore; two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end to be semi-circular in cross-sectional shape for receiving and grippingly engaging said polished rod in metal to metal contact; radially disposed bolts threaded into said damp body for manipulation of said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body; and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping From the well bore, said elastomeric seals being compressible to aliow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
This and other features of preferred embodiments of the present invention will become more apparent from the following description in which reference is made to the appended drawings in which:
Figure 1 is a view of a progressing cavity pump oil well installation in an earth formation with a typical drive head, wellhead frame and stuffing box;
Figure 2 is a view similar to the upper end of Figure 1 but i{iustrating a conventional drive head with an integrated stuffing box extending from the bottom end of the drive head;
Figure 3 is a side elevational, cross-sectional view of one embodiment of a polished rod lock-out damp according to the present invention;
Figure 4 is a top plan view of the clamp of Figure 3;
Figure 5 is a side elevational, cross-sectional view of another embodiment of a polished rod lock-out clamp according to the present invention;
Figure 6 is a top plan view of the claim of Figure 4;
Figure 7is a side elevational, cross-sectional view of another embodiment of a polished rod lock-out clamp according to the present invention;
Figure 8 is a top plan view of the clamp of Figure 7;
Figure 9 is a side elevational, cross-sectional view of one embodiment of a blow out preventer having an integrated polished rod lock-out clamp according to the present invention; and Figure 10 is a top plan view of the clamp of Figure 9.
Figure 11 is a view of the drive head of Figure 2 with a cross-sectional view of a polished rod lock out clamp connected.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Figure 1 illustrates a known progressing cavity pump installation 10. The installation includes a typical progressing cavity pump drive head 12 , a wellhead frame 14 , a stuffing box 16 , an electric motor 18, and a belt and sheave drive system 20, alt mounted on a flow tee 22. The flow tee is shown with a blow out preventer 24 which is, in tum, mounted on a wellhead 25. The drive head supports and drives a drive shaft 26, generally known as a "polished rod". The polished rod is supported and rotated by means of a polish rod clamp 28, which engages an output shaft 30 of the drive head by means of milled slots (not shown) in both parts. Wellhead frame 14 is open sided in order to expose polished rod 26 to allow a service crew to install a safety clamp on the polished rod and then perform maintenance work on stuffing box 16 . Polished rod 26 rotationally drives a drive string 32, sometimes referred to as "sucker rods", which, in tum, drives a progressing cavity pump 34 located at the bottom of the installation to produce well fluids to the surface through the wellhead.
Figure 2 illustrates a typical progressing cavity pump drive head 36 with an integral stuffing box 38 mounted on the bottom of the drive head and corresponding to that portion of the installation in Figure 1 which is above the dotted and dashed line 40.
The main advantage of this type of drive head is that, since the main drive head shaft is already supported with bearings, stuffing box seals can be placed around the main shaft, thus improving alignment and eliminating contact between the stuffing box rotary seals and the polished rod. This style of drive head reduces the height of the installation because there is no wellhead frame and also reduces cost because there is no wellhead frame and there are fewer parts since the stuffing box is integrated with the drive head. The main disadvantage is that the drive head must be removed to do maintenance work on the stuffing box. This necessitates using a service rig with two lifting lines, one to support the polished rod and the other to support the drive head.
In order to overcome the above disadvantages, the present invention provides a polished rod lock-out clamp for use in clamping the polished rod during drive head servicing operations. The clamp can be integrated with the drive head or provided as a separate assembly below the drive.
One aspect of the present invention is the provision of a polished rod lock out clamp 160 for use in securing the polished rod when it is desired to service the drive head. The clamp may be integrated into the drive head or may be provided as a separate assembly, which is secured to and between the drive head and a flow tee, as illustrated in Figure 11.
Figures 3-6 illustrate two embodiments of a lock-out clamp. As shown, in each embodiment, the clamp includes a tubular clamp body 162 having a bore 164 for receiving polished rod 26 in annularly spaced relation therethrough. A bushing 166 is mounted on an annular shoulder 168 formed at the bottom end of bore 164 for centering the polished rod in the housing. Flanges 167 or threaded connections depending on the application are formed at the upper and lower ends of the housing for bolting or otherwise securing the housing to the underside of the drive head and to the upper end of the flow tee. The clamp includes two or more equally angularly spaced clamp members or shoes 170 about the axis of the housing/polished rod. The clamp shoes are generally in the form of a segment of a cylinder with an arcuate inner surface 172 dimensioned to correspond to the curvature of the surface of the polished rod. Arcuate inner surfaces 172 should be undersize relative to the polished rod's diameter to enhance gripping force. In the embodiment of Figures 3 and 4, spring means 174 are provided to normally bias the clamp members into an un-clamped position.
In the embodiment of Ftgures 5 and 6, the ends of bolts 176 are generally T-shaped to hook into correspondingly shaped slots 169 in shoes 170 to positively retract the shoes without the need for springs 174.
Clamp shoes 170 are actuated by radial bolts 176, for example, to clamp the polished rod such that it cannot turn or be displaced axially. The lock out clamp may be located between the flow tee and the bottom of the drive head. Alternately, it can be built into the drive head.
Figure 4 is a top plan view of the clamp of Figure 3;
Figure 5 is a side elevational, cross-sectional view of another embodiment of a polished rod lock-out clamp according to the present invention;
Figure 6 is a top plan view of the claim of Figure 4;
Figure 7is a side elevational, cross-sectional view of another embodiment of a polished rod lock-out clamp according to the present invention;
Figure 8 is a top plan view of the clamp of Figure 7;
Figure 9 is a side elevational, cross-sectional view of one embodiment of a blow out preventer having an integrated polished rod lock-out clamp according to the present invention; and Figure 10 is a top plan view of the clamp of Figure 9.
Figure 11 is a view of the drive head of Figure 2 with a cross-sectional view of a polished rod lock out clamp connected.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Figure 1 illustrates a known progressing cavity pump installation 10. The installation includes a typical progressing cavity pump drive head 12 , a wellhead frame 14 , a stuffing box 16 , an electric motor 18, and a belt and sheave drive system 20, alt mounted on a flow tee 22. The flow tee is shown with a blow out preventer 24 which is, in tum, mounted on a wellhead 25. The drive head supports and drives a drive shaft 26, generally known as a "polished rod". The polished rod is supported and rotated by means of a polish rod clamp 28, which engages an output shaft 30 of the drive head by means of milled slots (not shown) in both parts. Wellhead frame 14 is open sided in order to expose polished rod 26 to allow a service crew to install a safety clamp on the polished rod and then perform maintenance work on stuffing box 16 . Polished rod 26 rotationally drives a drive string 32, sometimes referred to as "sucker rods", which, in tum, drives a progressing cavity pump 34 located at the bottom of the installation to produce well fluids to the surface through the wellhead.
Figure 2 illustrates a typical progressing cavity pump drive head 36 with an integral stuffing box 38 mounted on the bottom of the drive head and corresponding to that portion of the installation in Figure 1 which is above the dotted and dashed line 40.
The main advantage of this type of drive head is that, since the main drive head shaft is already supported with bearings, stuffing box seals can be placed around the main shaft, thus improving alignment and eliminating contact between the stuffing box rotary seals and the polished rod. This style of drive head reduces the height of the installation because there is no wellhead frame and also reduces cost because there is no wellhead frame and there are fewer parts since the stuffing box is integrated with the drive head. The main disadvantage is that the drive head must be removed to do maintenance work on the stuffing box. This necessitates using a service rig with two lifting lines, one to support the polished rod and the other to support the drive head.
In order to overcome the above disadvantages, the present invention provides a polished rod lock-out clamp for use in clamping the polished rod during drive head servicing operations. The clamp can be integrated with the drive head or provided as a separate assembly below the drive.
One aspect of the present invention is the provision of a polished rod lock out clamp 160 for use in securing the polished rod when it is desired to service the drive head. The clamp may be integrated into the drive head or may be provided as a separate assembly, which is secured to and between the drive head and a flow tee, as illustrated in Figure 11.
Figures 3-6 illustrate two embodiments of a lock-out clamp. As shown, in each embodiment, the clamp includes a tubular clamp body 162 having a bore 164 for receiving polished rod 26 in annularly spaced relation therethrough. A bushing 166 is mounted on an annular shoulder 168 formed at the bottom end of bore 164 for centering the polished rod in the housing. Flanges 167 or threaded connections depending on the application are formed at the upper and lower ends of the housing for bolting or otherwise securing the housing to the underside of the drive head and to the upper end of the flow tee. The clamp includes two or more equally angularly spaced clamp members or shoes 170 about the axis of the housing/polished rod. The clamp shoes are generally in the form of a segment of a cylinder with an arcuate inner surface 172 dimensioned to correspond to the curvature of the surface of the polished rod. Arcuate inner surfaces 172 should be undersize relative to the polished rod's diameter to enhance gripping force. In the embodiment of Figures 3 and 4, spring means 174 are provided to normally bias the clamp members into an un-clamped position.
In the embodiment of Ftgures 5 and 6, the ends of bolts 176 are generally T-shaped to hook into correspondingly shaped slots 169 in shoes 170 to positively retract the shoes without the need for springs 174.
Clamp shoes 170 are actuated by radial bolts 176, for example, to clamp the polished rod such that it cannot turn or be displaced axially. The lock out clamp may be located between the flow tee and the bottom of the drive head. Alternately, it can be built into the drive head.
In some appNcaUons It Is preferable not to restrict the diameter through the bore 1 di of the lodc out damp so that the sudcer rods can be pulled tlrough the damp 160. In thils embodiment of the polish rod damp as shown in Figure 7 and 8, where Iike numerals identity like elements, two opposing radial pistona 182 are actuated by bolts 184 to force the piskns togedhar and anwnd pdish rod Ze. The poAsh rod is gipped by waate reoesses 1 Sd, which are preferably made undersize reiative to the polisftted rod to enhance grippinp force. Pistons 182 further indude 0-rings 223 to provkie a bettsr seai In bore.164:
In a furlher embodiment of the poNshed rod todc out damp, the damping means are integrated with a bbw out preventer 180, shown in Figuns 9 and 10. Bkyw out pr+avenesrs are required on most oil weps. They traditionaNy have two opposing radial pistons 182 actuated by bolts 184 to force ft pistons together and around the poiish rod to effed a seal.
The pistons are generally made of eiastomsr or provided with an elastomsdc Bner such that when the pistons are forced together by the bolts, a seal Is formed betvireen the pistons, between the pistons and the polish rod and between the pistons and the piston bores.
Actuation thus serves as a means to prevent weN flukb from escaping from the weN.
In accordance with the present invention, an improved blow out preventsr satves as a lock out damp for'weN servidng. In order to serve this purpose, the pistons must be substantisk of metal which can be forced against the poflshed rod to prevent axial or rotationsi motion thereof. The Inner end of the pistons Is formed with an arcuate recess 1SO
with curvatufe corresponding substantlapy to that of the polished rod.
Enhanoed gripping torcre can be adNeved if the arouate recoss diameter Is undenrize relatlve to the polistbd rod.
The sealing function oi the blow out preventsr must still be acoomplished.
This can be done by providing a narrow elastomeric seal 188 which runs across the vertical flat face of the piston, akmg the arc.vate recess; a"the mid heigM of the piston and then dnxunterentiaaNy, around the piston. The seals can compress Into the grooves which pennits the platons to engage the polished rod In metal to metal contaat. Seal 188 seais between the pistons, between the pistons and the poqsh rod and between the pistons and the piston bores. Thus, well fluid is prevented from,coming up the well bore and escaphg while the wep Is being serviced, as might be the case while the stufflng box Is being repaired. By induding tha sealing func8on d the BOP with clamping means, one set of pistons can aooompHah both functions, enhancing safety and convenience without increasing cost or size.
It will be understood by one skilled in the art that, in stating that the pistons must be substantially of metal, and that the pistons engage the polished md in metal to metal contact, it Is not intended to exdude the use of conventional non-metallic coatings that may be added to metallic surfaces for enhanced wear and/or gripping properties, such as certain oxides, carbides and ceramics.
The above-described embodiments of the present invention are meant to be illustrative of preferred embodiments and are not intended to 1imk the scope of the present inventlon. Varbus modHications, which would be'neadily apparent to one skiibd in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set. forth in the folkrwing clairhs appended hereto.
In a furlher embodiment of the poNshed rod todc out damp, the damping means are integrated with a bbw out preventer 180, shown in Figuns 9 and 10. Bkyw out pr+avenesrs are required on most oil weps. They traditionaNy have two opposing radial pistons 182 actuated by bolts 184 to force ft pistons together and around the poiish rod to effed a seal.
The pistons are generally made of eiastomsr or provided with an elastomsdc Bner such that when the pistons are forced together by the bolts, a seal Is formed betvireen the pistons, between the pistons and the polish rod and between the pistons and the piston bores.
Actuation thus serves as a means to prevent weN flukb from escaping from the weN.
In accordance with the present invention, an improved blow out preventsr satves as a lock out damp for'weN servidng. In order to serve this purpose, the pistons must be substantisk of metal which can be forced against the poflshed rod to prevent axial or rotationsi motion thereof. The Inner end of the pistons Is formed with an arcuate recess 1SO
with curvatufe corresponding substantlapy to that of the polished rod.
Enhanoed gripping torcre can be adNeved if the arouate recoss diameter Is undenrize relatlve to the polistbd rod.
The sealing function oi the blow out preventsr must still be acoomplished.
This can be done by providing a narrow elastomeric seal 188 which runs across the vertical flat face of the piston, akmg the arc.vate recess; a"the mid heigM of the piston and then dnxunterentiaaNy, around the piston. The seals can compress Into the grooves which pennits the platons to engage the polished rod In metal to metal contaat. Seal 188 seais between the pistons, between the pistons and the poqsh rod and between the pistons and the piston bores. Thus, well fluid is prevented from,coming up the well bore and escaphg while the wep Is being serviced, as might be the case while the stufflng box Is being repaired. By induding tha sealing func8on d the BOP with clamping means, one set of pistons can aooompHah both functions, enhancing safety and convenience without increasing cost or size.
It will be understood by one skilled in the art that, in stating that the pistons must be substantially of metal, and that the pistons engage the polished md in metal to metal contact, it Is not intended to exdude the use of conventional non-metallic coatings that may be added to metallic surfaces for enhanced wear and/or gripping properties, such as certain oxides, carbides and ceramics.
The above-described embodiments of the present invention are meant to be illustrative of preferred embodiments and are not intended to 1imk the scope of the present inventlon. Varbus modHications, which would be'neadily apparent to one skiibd in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set. forth in the folkrwing clairhs appended hereto.
Claims (63)
1. A polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore;
and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in metal to metal contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore;
and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in metal to metal contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
2. A clamp as defined in claim 1, each said clamp member being radially movable with respect to said polished rod and having an arcuate inner surface for engaging said polished rod thereinto.
3. A clamp as defined in claim 2, wherein the diameter of said inner surface is slightly less than the diameter of the polished rod to enhance gripping force.
4. A clamp as defined in claims 1, 2 or 3, wherein each said clamp member is in the form of a piston, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said bore of said clamp body, each said piston having an inner end proximate said bore of said clamp body, said arcuate inner surface being formed in said inner end to be semi-circular in shape for receiving and grippingly engaging said polished rod.
5. A clamp as defined in claim 4, comprising a pair of said pistons radially opposed to one another.
6. A clamp as defined in claim 5, said pistons having mutually engageable end faces at said inner ends thereof and seal means disposed between said end faces, said pistons being sealingly disposed in said piston bores and being sealingly engageable with said polished rod and with each other to prevent well fluids from escaping past said clamp when said pistons are disposed in said gripping positions thereof.
7. A clamp as defined in claims 2 or 3, said clamp members comprising a pair of opposed clamp members each forming an elongated segment of a cylinder and each having a said arcuate inner surface for engagement with the polished rod.
8. A clamp as defined an any of claims 1 to 7 including resilient members disposed between said clamp members to normally bias said clamp members towards said retracted position thereof.
9. A clamp as defined in any of claims 1 to 8, said manipulating means including, for each clamp member, a bolt threaded into said clamp body for moving said clamp member between said gripping and retracted positions thereof.
10. The clamp as defined in claim 9, wherein each said bolt includes a shaped portion formed on an inner end thereof for mating engagement with a correspondingly shaped slot in a respective clamp member for moving said members into said retracted position thereof.
11. A clamp as defined in any of claims 1 to 10, wherein said clamp is arranged to be secured between a polished rod drive head and a well head of the oil well installation.
12. A clamp as defined in any of claims 1 to 11, wherein said clamp forms part of a drive head for driving the polished rod.
13. A clamp as defined in any of claims 1 to 12, further including means for centering said polished rod in said bore of said clamp body.
14. A clamp as defined in any of claims 1 to 13, further including means for axially locating said clamp members in said clamp body and for transferring axial and rotational loads from said clamp members to said clamp body.
15. A polished rod lock out clamp for use to temporarily suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
metal clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for metal to metal contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
metal clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for metal to metal contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
16. A clamp as defined in claim 15, wherein the diameter of said recess is slightly less than the diameter of the outer surface of said polished rod to enhance gripping force.
17. A clamp as defined in claims 15 or 16, said clamp body further having piston bores extending radially of said bore of said clamp body, each said clamp member comprising a piston disposed in a piston bore, each piston having an inner end in which said recess is formed for receiving and grippingly engaging the polished rod.
18. A clamp as defined in claim 17, comprising a pair of said pistons radially opposed to one another.
19. A clamp as defined in claims 15 or 16, wherein said clamp members comprise two or more opposed clamp members each forming an elongated segment of a cylinder and each having said recess formed therein for engagement with the polished rod and an arcuate outer surface for engagement with said bore of said clamp body.
20. A clamp as defined in claims 15,16,17,18 or 19, said manipulating means including a bolt secured to each said clamp member, said bolts being threadedly engaged with respective radially extending threaded holes in said clamp body for radial movement of said bolts and said clamp members, said bolts extending outwardly of said clamp body for manipulation thereof.
21. A clamp as defined in any of claims 15 to 20, each said clamp member having a dovetail slot and a dovetail key formed on inner ends of said bolts for mating engagement with said dovetail slots for securing said bolts and associated clamp members.
22. A clamp as defined in any of claims 15 to 21 including resilient members disposed between said clamp members to normally bias said clamp members towards said retracted position thereof.
23. A combined blow out preventer and polished rod lock out clamp for use in an oil well installation, comprising:
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a metallic piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a metallic piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
24. A clamp as defined in claim 23, wherein said manipulating means include a bolt secured to each said piston, said bolts being threadedly engaged with radially extending threaded holes in said clamp body for radial movement of said bolts and said pistons, said bolts extending outwardly of said clamp body for manipulation thereof.
25. A clamp as defined in claims 23 or 24 including resilient members disposed between said clamp members to normally bias said clamp members towards said retracted position thereof.
26. A clamp as defined in claim 23, 24 or 25, wherein the diameter of said curved recess is slightly less than the diameter of the outer surface of the polished rod.
27. The clamp as defined in claim 24,25 or 26, wherein each said bolt includes a shaped portion formed on an inner end thereof for mating engagement with a correspondingly shaped slot in a respective clamp member for moving said members into said retracted position thereof.
28. A polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body having an elongated arcuate inner metallic surface for grippingly engaging the polished rod in metal to metal contact, each said clamp member being radially moveable with respect to the polished rod; and radially disposed bolts threaded into said clamp body for manipulation of said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod relative to said axial bore of said clamp body.
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body having an elongated arcuate inner metallic surface for grippingly engaging the polished rod in metal to metal contact, each said clamp member being radially moveable with respect to the polished rod; and radially disposed bolts threaded into said clamp body for manipulation of said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod relative to said axial bore of said clamp body.
29. A clamp as defined in claim 28, wherein said radially disposed bolts have T-shaped inner portions to hook into correspondingly shaped slots in said clamp members to move said clamp members to said retracted position thereof.
30. A clamp as defined in claims 28 or 29, wherein said clamp members comprise a pair of opposed clamp members each forming an elongated segment of a cylinder and each having on an inner surface thereof said arcuate inner surface for engagement with the polished rod, and a curved outer surface for contact with said bore of said clamp body.
31. A clamp as defined in claim 28 or 29, wherein each said clamp member is in the form of a piston, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, said arcuate inner surface being formed in said inner end to be semi-circular in shape for receiving and grippingly engaging said polished rod.
32. A clamp as defined in claim 31, comprising a pair of said pistons radially opposed to one another.
33. A clamp as defined in any of claims 27 to 31, wherein the diameter of said arcuate inner surface is slightly less than the diameter of the outer surface of the polished rod for enhanced gripping force.
34. A clamp as defined in claims 31, 32 or 33, said pistons having mutually engageable end faces at said inner ends thereof and seal means disposed between said end faces, said pistons being sealingly disposed in said piston bores and being sealingly engageable with said polished rod and with each other to prevent well fluids from escaping past said clamp when said pistons are disposed in said gripping positions thereof.
35. A polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end to be semi-circular in cross-sectional shape for receiving and grippingly engaging said polished rod in metal to metal contact;
radially disposed bolts threaded into said clamp body for manipulation of said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body; and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end to be semi-circular in cross-sectional shape for receiving and grippingly engaging said polished rod in metal to metal contact;
radially disposed bolts threaded into said clamp body for manipulation of said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body; and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
36. A clamp as defined in claim 35, wherein the radius of curvature of said arcuate inner surface is slightly less than the radius of curvature of the outer surface of the polished rod.
37. A clamp as defined in claims 35 or 36, wherein said radially disposed bolts have T-shaped inner portions to hook into correspondingly shaped slots in said clamp members to retract said clamp members to said retracted positions thereof.
38. A polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in non-elastomeric frictional contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in non-elastomeric frictional contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
39. A polished rod lock out clamp operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in hard surface to hard surface contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore for receiving the polished rod therethrough in spaced relation to said bore;
clamp members in said clamp body for gripping the polished rod in said bore; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage said polished rod in hard surface to hard surface contact therebetween to prevent rotation or axial movement of the polished rod, and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
40. A clamp as defined in claims 38 or 39, each said clamp member being radially movable with respect to said polished rod and having an arcuate inner surface for engaging said polished rod thereinto.
41. A clamp as defined in claim 40, wherein the diameter of said inner surface is slightly less than the diameter of the polished rod to enhance gripping force.
42. A clamp as defined in claims 38, 39, 40 or 41, wherein each said clamp member is in the form of a piston, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said bore of said clamp body.
43. A clamp as defined in claim 42, comprising a pair of said pistons radially opposed to one another.
44. A clamp as defined in claim 43, said pistons having mutually engageable end faces at said inner ends thereof and seal means disposed between said end faces, said pistons being sealingly disposed in said piston bores and being sealingly engageable with said polished rod and with each other to prevent well fluids from escaping past said clamp when said pistons are disposed in said gripping positions thereof.
45. A clamp as defined in claims 40 or 41, said clamp members comprising a pair of opposed clamp members each forming an elongated segment of a cylinder.
46. A polished rod lock out clamp for use to temporarily suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for non-elastomeric frictional contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for non-elastomeric frictional contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
47. A polished rod lock out clamp for use to temporarily suspend a polished rod in an oil well installation, comprising:
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for hard surface to hard surface contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
a clamp body having a bore therethrough for receiving the polished rod in spaced relation to said bore;
clamp members in said clamp body for engaging the polished rod in said bore, each said clamp member being radially movable with respect to the polished rod and each having a recess formed therein for grippingly receiving and engaging said polished rod for hard surface to hard surface contact therewith; and manipulating means secured to said clamp body and said clamp members for moving said clamp members between a polished rod gripping position in which said clamp members grippingly engage the polished rod to prevent rotation or axial movement thereof and a retracted position in which said clamp members are removed from the polished rod to permit rotational and axial movement of the polished rod in said bore of said clamp body.
48. A clamp as defined in claims 46 or 47, wherein the diameter of said recess is slightly less than the diameter of the outer surface of said polished rod to enhance gripping force.
49. A clamp as defined in claims 46, 47, or 48, said clamp body further having piston bores extending radially of said bore of said clamp body, each said clamp member comprising a piston disposed in a piston bore, each piston having an inner end in which said recess is formed for receiving and grippingly engaging the polished rod.
50. A clamp as defined in claim 49, comprising a pair of said pistons radially opposed to one another.
51. A clamp as defined in claims 46, 47 or 48, wherein said clamp members comprise two or more opposed clamp members each forming an elongated segment of a cylinder and each having said recess formed therein for engagement with the polished rod and an arcuate outer surface for engagement with said bore of said clamp body.
52. A combined blow out preventer and polished rod lock out clamp for use in an oil well installation, comprising:
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in non-elastomeric frictional contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in non-elastomeric frictional contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
53. A combined blow out preventer and polished rod lock out clamp for use in an oil well installation, comprising:
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in hard surface to hard surface contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
a housing having a bore for receiving a polished rod in spaced relation therethrough and opposed bores extending radially of said bore of said housing;
clamp members in said housing for grippingly engaging said polished rod in said bore, each said clamp member comprising a piston disposed in one of said radial bores, each piston having an inner end and a concavely curved recess in said inner end for receiving and grippingly engaging said polished rod in hard surface to hard surface contact along at least a portion of the length of said recess to suspend said polished rod in said oil well installation;
elastomeric seal means to provide a seal between a portion of the length of said recess in said piston and said polished rod, a seal between said pistons and sealing of each piston in its associated radial bore to prevent well fluid from coming up a well bore and escaping to the exterior of the well bore when said pistons grippingly engage the polished rod; and manipulating means secured to said housing and said pistons for moving said pistons between a polished rod gripping position in which said pistons grippingly engage said polished rod to prevent rotation or axial movement thereof and a retracted position in which said pistons are removed from said polished rod to permit rotational and axial movement of said polished rod in said bore of said clamp housing.
54. A clamp as defined in claims 52 or 53, wherein the diameter of said curved recess is slightly less than the diameter of the outer surface of the polished rod.
55. A polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in metal to metal contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
56. A polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in hard surface to hard surface contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make hard surface to hard surface contact with said polished rod when said pistons are in said gripping position thereof.
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in hard surface to hard surface contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make hard surface to hard surface contact with said polished rod when said pistons are in said gripping position thereof.
57. A polished rod lock out clamp, with blow out preventer seals, operable to suspend a polished rod in an oil well installation, comprising:
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in non-elastomeric frictional contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make non-elastomeric frictional contact with said polished rod when said pistons are in said gripping position thereof.
a clamp body having an axial bore for receiving the polished rod in spaced relation to said bore;
two radially opposed pistons acting as clamp members, said clamp body having a piston bore for each said piston, each said piston bore extending radially of said axial bore of said clamp body, each said piston having an inner end proximate said axial bore of said clamp body, an arcuate inner surface being formed in said inner end for receiving and grippingly engaging said polished rod in non-elastomeric frictional contact;
manipulating means secured to said clamp body and said clamp members for moving said pistons between a polished rod gripping position in which said pistons grippingly engage the polished rod to prevent rotation or axial movement of the polished rod and a retracted position in which said pistons are removed from the polished rod to permit rotational and axial movement of the polished rod in said axial bore of said clamp body;
and said pistons each having an elastomeric seal to seal between the polished rod and a portion of the length of said arcuate inner surface in each said piston, between said opposed pistons and between each said piston and its associated radial bore to prevent well fluids from escaping from the well bore, said elastomeric seals being compressible to allow said pistons to make non-elastomeric frictional contact with said polished rod when said pistons are in said gripping position thereof.
58. A clamp as defined in claims 55, 56 or 57, wherein the radius of curvature of said arcuate inner surface is slightly less than the radius of curvature of the outer surface of the polished rod.
59. A clamp as defined in any of claims 35 to 37, 55 or 58, wherein said elastomeric seal is mounted in a groove in said arcuate inner surface in each piston, and is compressible into said groove to allow said pistons to make metal to metal contact with said polished rod when said pistons are in said gripping position thereof.
60. A clamp as defined in claims 56 or 58, wherein said elastomeric seal is mounted in a groove in said arcuate inner surface in each piston, and is compressible into said groove to allow said pistons to make hard surface to hard surface contact with said polished rod when said pistons are in sa-id gripping position thereof.
61. A clamp as defined in claims 57 or 58, wherein said elastomeric seal is mounted in a groove in said arcuate inner surface in each piston, and is compressible into said groove to allow said pistons to make non-elastomeric frictional contact with said polished rod when said pistons are in said gripping position thereof.
62. A clamp as defined in any of claims 1 to 61, wherein a non-metallic coating is applied to the gripping surface of the clamp members.
63. A clamp as defined in claim 62, wherein said non-metallic coating comprises an oxide, carbide or ceramic selected to decrease the wear of said clamp members or to increase the gripping properties of the contact between said clamp members and the polished rod.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002349988A CA2349988E (en) | 2000-06-09 | 2001-06-11 | Polish rod locking clamp |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2,311,036 | 2000-06-09 | ||
| CA002311036A CA2311036A1 (en) | 2000-06-09 | 2000-06-09 | Pump drive head with leak-free stuffing box, centrifugal brake and polish rod locking clamp |
| CA002349988A CA2349988E (en) | 2000-06-09 | 2001-06-11 | Polish rod locking clamp |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| CA2349988A1 CA2349988A1 (en) | 2001-10-10 |
| CA2349988C CA2349988C (en) | 2002-05-07 |
| CA2349988E true CA2349988E (en) | 2008-01-22 |
Family
ID=25681871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002349988A Expired - Lifetime CA2349988E (en) | 2000-06-09 | 2001-06-11 | Polish rod locking clamp |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2349988E (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2311036A1 (en) | 2000-06-09 | 2001-12-09 | Oil Lift Technology Inc. | Pump drive head with leak-free stuffing box, centrifugal brake and polish rod locking clamp |
| US6557643B1 (en) | 2000-11-10 | 2003-05-06 | Weatherford/Lamb, Inc. | Rod hanger and clamp assembly |
| US7000888B2 (en) | 2004-03-29 | 2006-02-21 | Gadu, Inc. | Pump rod clamp and blowout preventer |
| US7552765B2 (en) | 2006-01-27 | 2009-06-30 | Stream-Flo Industries Ltd. | Wellhead blowout preventer with extended ram for sealing central bore |
| US7673674B2 (en) | 2006-01-31 | 2010-03-09 | Stream-Flo Industries Ltd. | Polish rod clamping device |
| US8544535B2 (en) | 2010-02-12 | 2013-10-01 | Cameron International Corporation | Integrated wellhead assembly |
| DE102010013666A1 (en) * | 2010-04-01 | 2011-10-06 | Netzsch-Mohnopumpen Gmbh | Method for removing an eccentric screw drive of a petroleum feed pump and petroleum feed pump |
| DE102011018755B4 (en) | 2011-04-27 | 2013-10-24 | Netzsch Pumpen & Systeme Gmbh | Reversing protection for borehole pumps |
| CN105781468A (en) * | 2016-03-02 | 2016-07-20 | 中国石油天然气股份有限公司 | Wellhead polish rod sealing device with blowout prevention valve |
| CN110424904A (en) * | 2019-09-03 | 2019-11-08 | 王瑞东 | Integral type polished rod eye |
| CN113700751B (en) * | 2021-06-11 | 2023-01-06 | 江西昌河航空工业有限公司 | Locking device and method for swivel joint bearing |
-
2001
- 2001-06-11 CA CA002349988A patent/CA2349988E/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2349988C (en) | 2002-05-07 |
| CA2349988A1 (en) | 2001-10-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| NARE | Reissued | ||
| MKEX | Expiry |
Effective date: 20210611 |