Horizontal butt joint salt cavern old well casing reaming device

Abstract

The invention relates to the field of oil and gas resource development, and provides a horizontal butt-joint salt cavern old well casing reaming device which comprises a reaming device body which comprises a body center hole extending along the axis, and a plurality of openings are evenly distributed in the side wall of the reaming device body in the circumferential direction. The cutter feeding rod is arranged in the body center hole in a sliding mode along the axis, and a cutter feeding rod center hole coaxial with the body center hole is formed in the cutter feeding rod; the reaming knife is pivotally connected to the reaming device body and can rotate between a retracting position and an opening position extending out of the opening; and the connecting rod mechanism is used for connecting the reaming cutter to the cutter feeding rod so as to limit the opening angle of the reaming cutter at the opening position. The reaming device can improve reaming efficiency and ensure safe construction.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas resource development, and relates to a new type of eye-expanding device used after the casing section of the plugging layer section is milled for the horizontal docking of a salt cavern gas storage reservoir with a salt cavern old well plugging operation. Background Art

[0002] The existing salt cavern gas storage horizontally docked with the old salt cavern wells often have problems such as casing deformation and corrosion, poor cementing quality and sealing conditions, and small well diameter. They are not suitable for direct conversion into injection and production gas wells, and need to be plugged in the old wells in the area. To ensure the reliability of plugging, the well section after milling can be expanded to 265 mm to 270 mm, so as to ensure that the annulus is plugged to the formation and ensure the safety of subsequent gas storage operations.

[0003] Usually, the single safe reaming size is 30 to 50 mm, while the reaming size under special reaming construction conditions needs to reach more than 90 mm. At the same time, due to the limitation of the diameter of the traditional upper 7-inch casing, the reamer cutter body is required to be more than 120 mm larger than the main body after being extended, and the reaming diameter is relatively large. Large-diameter reaming construction increases the torque of the reaming tool, affects the mechanical drilling speed and service life of the tool during reaming construction, and is prone to complex situations underground. At the same time, the crystal particles of rock salt formations are large, brittle, and easy to break. During the reaming process, the contact surface is unstable and easily crushed, resulting in drilling stagnation, affecting construction efficiency and underground safety.

[0004] At present, the eye-expanding tools in the domestic market are mainly hydraulic expansion structures. The single eye-expanding size of domestic products is only 30 to 50 mm, which cannot adapt to the construction conditions of larger eye-expanding sizes. Therefore, eye-expanding tools need to be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a horizontally docked salt cavern old well casing reaming device suitable for large-size reaming conditions, so as to improve the reaming efficiency and ensure safe construction.

[0006] In order to solve at least one of the above technical problems, the present invention adopts the following technical solution:

[0007] According to the present invention, a horizontally docked salt cavern old well casing reaming device is provided, comprising: a reaming device body, comprising a body center hole extending along an axis, and having a plurality of openings evenly distributed along a circumferential direction on a side wall; a knife feed rod, slidably arranged in the body center hole along the axis, and having a knife feed rod center hole coaxial with the body center hole; a reaming knife, pivotally connected to the reaming device body, and rotatable between a retracted position and an open position extending from the opening; and a connecting rod mechanism, connecting the reaming knife to the knife feed rod to limit the opening angle of the reaming knife when it is in the open position.

[0008] According to one embodiment of the present invention, the reaming device body includes, in sequence along a first direction parallel to the axis: a first body section; and a second body section, whose inner diameter is smaller than the inner diameter of the first body section; wherein a first step portion of the body is formed at the junction of the first body section and the second body section.

[0009] According to one embodiment of the present invention, the tool feeding rod includes, in sequence along the first direction: a first section of the tool feeding rod, whose outer diameter matches the inner diameter of the first section of the main body; a second section of the tool feeding rod, whose outer diameter matches the inner diameter of the second section of the main body; and a third section of the tool feeding rod, which is configured to connect the reaming knife; wherein a step portion of the tool feeding rod is formed at the junction of the first section of the tool feeding rod and the second section of the tool feeding rod.

[0010] According to one embodiment of the present invention, the third section of the tool feeding rod has a wedge-shaped side surface, wherein the distance from the wedge-shaped side surface to the axis gradually decreases along the first direction; when the reaming knife is located in the retracted position, the back of the knife is arranged against the wedge-shaped side surface.

[0011] According to one embodiment of the present invention, the knife feeding rod comprises a flow limiting nozzle, which is arranged in the central hole of the knife feeding rod at the end of the first section of the knife feeding rod.

[0012] According to one embodiment of the present invention, the knife feeding rod comprises a sealing ring which is sleeved on the outer wall of the first section of the knife feeding rod so as to be sealingly and slidably connected with the inner wall of the first section of the body.

[0013] According to one embodiment of the present invention, the device includes: a return spring, which is confined in an annular cavity defined by the inner wall of the reaming device body, the outer wall of the tool feeding rod, the first step portion of the body and the step portion of the tool feeding rod, and is configured to be compressed / extended along the axis.

[0014] According to one embodiment of the present invention, the first section of the main body includes, in sequence along the first direction: a first segment of the first section of the main body; and a second segment of the first section of the main body, whose inner diameter is smaller than the inner diameter of the first segment of the first section of the main body; wherein a second step portion of the main body is formed at the junction of the first segment of the first section of the main body and the second segment of the first section of the main body.

[0015] According to one embodiment of the present invention, the device comprises: an adjustment ring detachably clamped at the second step portion of the body.

[0016] According to an embodiment of the present invention, the number of the adjustment rings is 1 to 4, and the thickness of each adjustment ring is 5 mm.

[0017] According to one embodiment of the present invention, the blade of the reaming knife is provided with cutting teeth, and the thickness of the blade is 30-35 mm.

[0018] According to one embodiment of the present invention, the connecting rod mechanism includes: a first rotating pin fixed to the tool feeding rod; a second rotating pin fixed to the reaming knife; and a connecting rod, which is respectively provided with a first rotating hole and a second rotating hole at both ends along the length direction, the first rotating hole can be rotatably mounted on the first rotating pin, and the second rotating hole can be rotatably mounted on the second rotating pin.

[0019] According to an embodiment of the present invention, the second rotating hole is an oblong hole, and the major axis direction of the oblong hole is consistent with the extending direction of the connecting rod.

[0020] According to one embodiment of the present invention, the device includes: an upper joint, which is detachably connected to one end of the reaming device body and has an upper joint center hole coaxial with the center hole of the body; wherein the outer diameter of the upper joint matches the inner diameter of the reaming device body, and the inner diameter of the upper joint is smaller than the outer diameter of the tool feed rod and larger than the inner diameter of the tool feed rod.

[0021] By adopting the above technical solution, the present invention has at least one of the following advantages compared with the prior art:

[0022] 1. Use the connecting rod and the tool feeding rod limit structure to limit the reamer to ensure the normal opening state of the blade to the greatest extent;

[0023] 2. Add a reset spring structure. After the fluid pressure difference disappears, the reset spring recovers the force to retract the reamer, effectively protecting the blade;

[0024] 3. The extension length of the reaming knife can be adjusted by adjusting the ring to limit the position of the knife feeding rod, which is suitable for different reaming diameter requirements;

[0025] 4. Thicken the reamer blade to improve the blade strength and ensure the effectiveness of reaming construction;

[0026] 5. The overall structure of the reaming device is reasonably designed. During the reaming process, the contact surface between the reaming cutter and the formation rock is stable, which effectively improves the reaming efficiency and ensures safe construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0028] Figure 1 Schematic diagram of a horizontal docking salt cavern old well casing reaming device according to the present invention;

[0029] Figure 2 is a schematic diagram of a reamer body according to the present invention;

[0030] Figure 3 is a schematic diagram of a knife feeding rod according to the present invention;

[0031] Figure 4 yes Figure 1 An enlarged view of the portion within the frame of the eye-reaming device shown.

[0032] In the figure:

[0033] 100 reaming device body, 110 first section of the body, 111 first subsection of the first section of the body, 112 second subsection of the first section of the body, 113 second step portion of the body, 120 second section of the body, 121 pivot, 122 opening, 130 first step portion of the body;

[0034] 200 a knife feed rod, 210 a first section of the knife feed rod, 220 a second section of the knife feed rod, 230 a third section of the knife feed rod, 240 a step portion of the knife feed rod, 250 a wedge-shaped side surface, 260 a flow limiting nozzle, 270 a sealing ring;

[0035] 300 return spring;

[0036] 400 adjustment ring;

[0037] 500 reamer, 510 back, 520 blade, 521 cutting teeth;

[0038] 600 connecting rod mechanism, 610 first rotating pin, 620 second rotating pin, 630 connecting rod;

[0039] 700 upper connector;

[0040] O is the axis, F is the first direction, K1 is the center hole of the body, K2 is the center hole of the tool rod, and K3 is the center hole of the upper joint. DETAILED DESCRIPTION

[0041] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the directions or positions indicated by the terms "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and should not be understood as limitations on the present technical solution.

[0043] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0044] In the specification and claims of the present invention and the above-mentioned drawings, when an element is referred to as being "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as being "connected to" another element, it may be directly or indirectly connected to the other element.

[0045] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] Figure 1 shows the overall structure of the horizontal docking salt cavern old well casing reaming device according to some embodiments of the present invention when it is in a working state and a non-working state, which generally includes: a reaming device body 100, a knife feeding rod 200, a reaming knife 500 and a connecting rod mechanism 600. Figure 2 and Figure 3 The specific structures of the reaming device body 100 and the knife feeding rod 200 according to some embodiments of the present invention are respectively shown. Figure 4The enlarged partial view shown shows the specific structure of the reaming knife 500 and the connecting rod mechanism 600 in detail. Specifically, the reaming device body 100 includes a body center hole K1 extending along its axis O, and a plurality of openings 122 are evenly distributed along the circumferential direction on the side wall. The number of openings 122 is consistent with the number of reaming knives 500. In an embodiment of the present invention, three openings 122 can be evenly distributed along the circumferential direction on the side wall of the reaming device body 100 to correspond to the three reaming knives 500 one by one. The knife feed rod 200 is slidably disposed in the body center hole K1 along the axis O, and has a knife feed rod center hole K2 coaxial with the body center hole K1. The reaming knife 500 can be pivotally connected to the reaming device body 100 at the pivot 121, and can rotate between a retracted position (non-working state) and an open position (working state) extending from the opening 122. The link mechanism 600 connects the reaming knife 500 to the knife feeding rod 200 and is configured to limit the opening angle of the reaming knife 500 when the reaming knife 500 is in the open position.

[0047] exist Figure 2 In the illustrated embodiment, the reaming device body 100 includes, in sequence, a first body section 110 and a second body section 120 along a first direction F parallel to the axis O. The inner diameter of the second body section 120 is smaller than the inner diameter of the first body section 110, and a first body step 130 is formed at the junction of the two. The tool feeding rod 200 can be designed to have an outer diameter size that matches the inner diameter size of the reaming device body 100, so as to form a piston structure in the body center hole K1 of the reaming device body 100.

[0048] exist Figure 3In the illustrated embodiment, the knife feeding rod 200 may include, in sequence along the first direction F: a knife feeding rod first section 210, a knife feeding rod second section 220 and a knife feeding rod third section 230. The outer diameter of the knife feeding rod first section 210 matches the inner diameter of the first section 110 of the body, and the two are slidably connected to form a piston structure. Preferably, the knife feeding rod 200 may include at least one sealing ring 270 sleeved on the outer wall of the knife feeding rod first section 210, so that it is sealed and slidably connected to the inner wall of the first section 110 of the body. The outer diameter of the knife feeding rod second section 220 may match the inner diameter of the second section 120 of the body. The knife feeding rod third section 230 is configured to connect the reamer 500, and its outer diameter may be consistent with the outer diameter of the knife feeding rod second section 220. Preferably, the third section 230 of the knife feeding rod may have a wedge-shaped side surface 250, the distance between the wedge-shaped side surface 250 and the axis O gradually decreases along the first direction F, and is arranged so that when the reamer 500 is in the retracted position, its blade back 510 abuts against the wedge-shaped side surface 250. Alternatively, the third section 230 of the knife feeding rod may be tapered as a whole, that is, the distance between the side wall of the section and the axis O gradually decreases uniformly along the first direction F. A knife feeding rod step portion 240 is formed at the junction of the first section 210 of the knife feeding rod and the second section 220 of the knife feeding rod. In an embodiment of the present invention, the knife feeding rod 200 may also include a flow limiting nozzle 260, which is arranged in the center hole K2 of the knife feeding rod at the end of the first section 210 of the knife feeding rod to play a throttling role.

[0049] Preferably, the reaming device according to the present invention may further include a reset spring 300, which is confined in an annular cavity defined by the inner wall of the reaming device body 100, the outer wall of the tool feeding rod 200, the first step portion 130 of the body and the step portion 240 of the tool feeding rod, and is configured to be compressed / stretched along the axis O to assist the reaming knife 500 in automatically resetting by means of elastic potential energy.

[0050] In another embodiment of the present invention, the first body section 110 of the reaming device body 100 may further include: a first body section first segment 111 and a first body section second segment 112 along the first direction. The inner diameter of the first body section second segment 112 is smaller than the inner diameter of the first body section first segment 111, and a second body step portion 113 is formed at the junction of the two. The second body step portion 113 may be used as a limiting structure to limit the maximum displacement of the tool feeding rod 200 in the first direction F.

[0051] Preferably, the reaming device may further include at least one adjustment ring 400. The adjustment ring 400 is detachably mounted on the second step portion 113 of the main body, and replaces the second step portion 113 of the main body as a limiting structure to limit the maximum displacement of the feed rod 200 in the first direction F. By installing adjustment rings 400 of different thicknesses and numbers, the stroke of the feed rod 200 can be adjusted, thereby controlling the opening angle of the reaming knife 500, which is suitable for different reaming diameter requirements. In an embodiment of the present invention, the number of adjustment rings is preferably 1 to 4, and the thickness of each adjustment ring can be 5 mm.

[0052] The connecting rod mechanism 600 may include: a first rotating pin 610 fixed to the knife feeding rod 200, a second rotating pin 620 fixed to the reaming knife 500, and a connecting rod 630. Specifically, the connecting rod 630 is provided with a first rotating hole and a second rotating hole at both ends along its length direction. The first rotating hole is rotatably sleeved on the first rotating pin 610, and the second rotating hole is rotatably sleeved on the second rotating pin 620. Based on the above structure, the connecting rod mechanism 600 can convert the linear movement of the knife feeding rod 200 along the axis O into the rotation of the reaming knife 500 around the pivot 121. Preferably, the second rotating hole sleeved on the second rotating pin 620 can be designed as an oblong hole, and the long axis direction of the oblong hole is consistent with the extension direction of the connecting rod 600. Thereby, the rotation of the reaming knife 500 can be smoother and not easy to get stuck.

[0053] The blade 520 of the reaming knife 500 is provided with cutting teeth 521, and the thickness of the blade is preferably 30 to 35 mm. Compared with the conventional blade with a thickness of about 20 mm, the reaming knife 500 is thickened in the present application to improve the strength of the blade body and ensure the effectiveness of the reaming construction.

[0054] Back to Figure 1 According to the reaming device of the present invention, the reaming device may further include an upper joint 700. The upper joint 700 is detachably connected to one end of the reaming device body 100 and has an upper joint center hole K3 coaxial with the body center hole K1. The outer diameter of the upper joint 700 matches the inner diameter of the reaming device body 100, and the inner diameter of the upper joint 700 is smaller than the outer diameter of the knife feeding rod 200 and larger than the inner diameter of the knife feeding rod 200. Based on the above structure, the end surface of the upper joint 700 extending into the body center hole K1 can be used as a limiting structure to limit the maximum displacement of the knife feeding rod 200 in the direction opposite to the first direction F.

[0055] The reaming device can be driven by a power mechanism, which can be a pump. During on-site construction, slowly rotate the turntable and start the pump, the drilling fluid enters the upper joint center hole K3 of the upper joint 700, there is throttling at the flow limiting nozzle 260, and the resulting pressure drop pushes the feed rod 200 downward along the first direction F; during the downward movement of the feed rod 200, the wedge-shaped side surface 250 of the third section 230 of the feed rod pushes the blade to extend outward; when the wedge-shaped side surface 250 descends to a certain position, the connecting rod mechanism 600 starts to move and continues to push the reaming knife 500 to expand outward. When the reaming knife 500 expands to a certain outer diameter, it begins to contact the well wall, and the cutting teeth 521 cut the well wall, and the reaming construction begins. When the feed rod 200 descends to the lower dead point, the outer diameter of the reaming knife 500 is limited, and the reaming knife 500 expands to the maximum. At this time, the pressure can be slowly applied to start reaming. When the reaming construction is completed, the pump is stopped, and the knife feed rod 200 moves upward under the action of the reset spring 300, and the connecting rod mechanism 600 is driven to retract. At this time, the retracting force of the connecting rod mechanism 600 acts on the reaming knife 500, and the reaming knife 500 is slowly retracted until it is retracted to the reaming device body 100, and then the tool is pulled out of the drill. The adjustment ring 400 limits the position of the knife feed rod 200 and adjusts the extension length of the reaming knife 500 to meet different reaming diameter requirements.

[0056] According to the reaming device of the present invention, the hydraulic pressure difference is used in the initial stage to make the wedge-shaped side push the reaming cutter 500 to expand initially, and the connecting rod mechanism 600 is used to push the cutter rod to continue to expand to the rated size in the second half of the expansion, thereby completing the expansion of the wellbore diameter. In an embodiment of the present invention, the preferred reaming construction parameters are drilling pressure 10-20 kN, rotation speed 40 rpm, and displacement 14-15 liters / second. Without the installation of the adjustment ring 400, the structure can expand the 177.8 mm wellbore to 270 mm, and the effective reaming size is greater than 90 mm. By installing adjustment rings 400 of different numbers and thicknesses, reaming construction of any size between 30 and 90 mm can be completed.

[0057] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0058] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0059] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A horizontal docking salt cavern old well casing reaming device, characterized in that: Include: The reaming device body (100) comprises a body center hole (K1) extending along an axis (O), and a plurality of openings (122) evenly distributed along a circumferential direction on a side wall; A knife feeding rod (200) is slidably arranged in the center hole (K1) of the body along the axis (O), and has a knife feeding rod center hole (K2) coaxial with the center hole (K1) of the body; A reaming knife (500) pivotally connected to the reaming device body (100) and rotatable between a retracted position and an open position extending from the opening (122); as well as A connecting rod mechanism (600) connects the reaming knife (500) to the knife feeding rod (200) to limit the opening angle of the reaming knife (500) when it is in the opening position.

2. The device according to claim 1, characterized in that The reaming device body (100) comprises, in sequence, along a first direction (F) parallel to the axis (O): a first body section (110); and The second section (120) of the body has an inner diameter smaller than the inner diameter of the first section (110) of the body; Wherein, a first step portion (130) of the main body is formed at the junction of the first section (110) of the main body and the second section (120) of the main body.

3. The device according to claim 2, characterized in that The knife feeding rod (200) comprises, in sequence along the first direction (F): The first section (210) of the knife feeding rod has an outer diameter that matches the inner diameter of the first section (110) of the body; The second section (220) of the knife feeding rod has an outer diameter that matches the inner diameter of the second section (120) of the body; as well as A third section (230) of the knife feeding rod is configured to connect to the reaming knife (500); and Wherein, a knife feeding rod step portion (240) is formed at the junction of the first section (210) of the knife feeding rod and the second section (220) of the knife feeding rod.

4. The device according to claim 3, characterized in that The third section (230) of the knife feeding rod has a wedge-shaped side surface (250), wherein: The distance between the wedge-shaped side surface (250) and the axis (O) gradually decreases along the first direction (F); When the reaming knife (500) is located at the retracted position, the knife back (510) is disposed against the wedge-shaped side surface (250).

5. The device according to claim 3, characterized in that The knife feeding rod (200) comprises a flow limiting nozzle (260) which is arranged in a central hole (K2) of the knife feeding rod at the end of the first section (210) of the knife feeding rod.

6. The device according to claim 3, characterized in that The knife feeding rod (200) comprises a sealing ring (270) which is sleeved on the outer wall of the first section (210) of the knife feeding rod so as to be sealingly and slidably connected with the inner wall of the first section (110) of the main body.

7. The device according to claim 3, characterized in that The device comprises: The return spring (300) is confined in an annular cavity defined by the inner wall of the reaming device body (100), the outer wall of the knife feeding rod (200), the first step portion (130) of the body and the step portion (240) of the knife feeding rod, and is configured to be compressed / stretched along the axis (O).

8. The device according to claim 2, characterized in that The first section (110) of the main body comprises, in sequence along the first direction (F): The first section of the main body and the first segment (111); and The second section (112) of the first section of the body has an inner diameter smaller than the inner diameter of the first section (111) of the first section of the body; Wherein, the second step portion of the main body is formed at the junction of the first section (111) of the main body and the second section (112) of the first section of the main body.

9. The device according to claim 8, characterized in that The device comprises: The adjusting ring (400) is detachably clamped on the second step portion of the body.

10. The device according to claim 9, characterized in that The number of the adjustment rings (400) is 1 to 4, and the thickness of each adjustment ring (400) is 5 mm.

11. The device according to claim 1, characterized in that The blade (520) of the reaming knife (500) is provided with cutting teeth (521), and the thickness of the blade is 30-35 mm.

12. The device according to claim 1, characterized in that The connecting rod mechanism (600) comprises: A first rotating pin (610) fixed to the knife feeding rod (200); A second rotation pin (620) fixed to the reaming knife (500); and The connecting rod (630) is provided with a first rotating hole and a second rotating hole at both ends along the length direction, respectively. The first rotating hole can be rotatably sleeved on the first rotating pin (610), and the second rotating hole can be rotatably sleeved on the second rotating pin (620).

13. The device according to claim 12, characterized in that The second rotating hole is an oblong hole, and the long axis direction of the oblong hole is consistent with the extension direction of the connecting rod (630).

14. The device according to claim 1, characterized in that The device comprises: An upper joint (700) is detachably connected to one end of the reaming device body (100) and has an upper joint center hole (K3) coaxial with the body center hole (K1); The outer diameter of the upper joint (700) matches the inner diameter of the reaming device body (100), and the inner diameter of the upper joint (700) is smaller than the outer diameter of the knife feeding rod (200) and larger than the inner diameter of the knife feeding rod (200).

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