CN215148667U

CN215148667U - Valve seat puller with hydraulic action

Info

Publication number: CN215148667U
Application number: CN202023118300.XU
Authority: CN
Inventors: 蒋仕斌; 胡绍贵; 杨文伟; 张�杰; 王志喜; 段太波; 黎恭成; 王俊玉; 吴燕; 张甜; 李天凡; 房伟; 王泰宝; 刘国川; 梁鹏; 徐铁军; 钟晨; 段萍; 李彦志; 李松林
Original assignee: Sichuan Baoshi Machinery Special Vehicle Co ltd; China National Petroleum Corp
Current assignee: Sichuan Baoshi Machinery Special Vehicle Co ltd; China National Petroleum Corp
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2021-12-14
Anticipated expiration: 2030-12-22

Abstract

The utility model discloses a valve seat puller with hydraulic action, which relates to the technical field of fracturing pumps and solves the technical problems of abnormal matching of a drawing screw rod and a drawing head, thread fracture and bonding, the utility model discloses have stopper and locking ring, the stopper is located the drawing head upper end, the stopper with draw the head upper end through the screw connection, the locking ring is located the lateral wall of drawing the head, the inner wall of locking ring and the lateral wall contact fit of drawing the head, the lower terminal surface of stopper has interior step, interior step is formed by the geometric center of stopper towards radial outside direction, the upper end of interior step gland drawing head; be used for drawing the lead screw and drawing the first good cooperation, the utility model provides improve equipment operating efficiency, the advantage of equipment good operation.

Description

Valve seat puller with hydraulic action

Technical Field

The utility model relates to a fracturing pump field especially relates to a ware structure is drawn to disk seat of hydraulic action for novel disk seat is drawn ware and can be realized drawing the lead screw and draw the first good cooperation and prevent that unusual cooperation causes thread damage or thread gluing behind the screw atress in the work.

Background

The valve seat main part is the key part of fracturing pump valve case assembly, and it assembles the downthehole, the seat of the valve seat main part of valve case body and reaches closely to eat and close the state in order to guarantee sealedly after real, and after working a period, the working surface of disk seat can take place the damage of certain degree, needs the maintenance to change the valve seat main part, just needs special disk seat puller to extract the valve seat main part.

The general valve seat puller is composed of the following main parts:

1. drawing a hydraulic cylinder, namely injecting liquid through a hydraulic pump to form high pressure, driving a drawing screw rod to move upwards by a hydraulic cylinder piston, and providing a pulling force F1 for drawing a valve seat;

2. the drawing screw rod is connected with a drawing head at the lower end and a drawing nut at the upper end, and has the function of opening a drawing hanging head and driving a drawing hook block to move upwards to draw out the valve seat main body;

3. the drawing head is connected with the drawing screw rod, the drawing head is unfolded to hook the lower end face of the valve seat main body after the drawing screw rod is screwed, and the drawing screw rod drives the drawing screw rod to hook the valve seat main body to move upwards so as to realize the function of drawing out the valve seat main body;

4. the drawing nut is in threaded connection with a drawing screw rod on a drawing hydraulic cylinder piston and can drive the drawing screw rod to move upwards.

Therefore, a novel valve seat puller needs to be designed, so that the screw rod can be pulled, the hook block can be well matched, the thread damage or thread gluing can be prevented due to abnormal matching after the thread is stressed in work, the puller can also effectively work even when the valve seat with tight interference in pulling fit is pulled, the novel valve seat puller also has good durability, and the safety and the reliability of construction operation are ensured.

Draw conventional staple bolt structure disk seat and innovate the improvement, novel staple bolt structure disk seat is drawn and is used intensity, the locking ring that rigidity is excellent replaces the staple bolt to lock and draws the couple piece, can let the screw thread (box) of drawing the head and the screw thread (pin thread) of pull rod lead screw be in normal cooperation state all the time, thereby effectively avoid the fracture of screw thread root or the bonding of screw thread face, make the disk seat draw the operation of drawing more reliable, safety, effectively improve equipment maintenance work efficiency, ensure the field device and well run.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: draw the ware in order to solve current disk seat and draw screw rod and draw abnormal fit behind the first work screw thread atress and cause thread damage or thread gluing to and draw the problem that screw rod and draw the fracture of first screw thread tooth root or the screw thread flank of tooth bonded, the utility model provides a disk seat of hydraulic pressure effect draws the ware.

The utility model discloses a realize above-mentioned purpose and specifically adopt following technical scheme:

the utility model provides a ware is drawn to disk seat of hydraulic action, includes disk seat main part, draws the head and draws the lead screw, the last lateral wall of disk seat main part is provided with the O circle groove, and the disk seat main part is the cone type, the O circle groove is located the central point of disk seat main part lateral wall and puts, and O circle inslot installs O type circle, draw the one end of lead screw with draw the inboard threaded connection of head, the lower extreme of drawing the head is formed with the barb, the upper surface of barb and the lower surface cooperation of disk seat main part, draw the ware still includes stopper and locking ring through the disk seat of hydraulic force effect, the stopper is located draws the overhead end, the stopper with draw the overhead end and pass through screwed connection, the locking ring is located the lateral wall of drawing the head, the inner wall of locking ring and the lateral wall contact cooperation of drawing the head, interior step has been seted up to the lower terminal surface of stopper, interior step is formed towards radial outside by the geometric centre of stopper, the upper end of the inner step gland pulling head.

The inner diameter range of the locking ring is phi 50-100mm, the outer diameter range is phi 65-120mm, the height range is 20-50mm, and the material of the locking ring is any one of 40CrNiMo, 45CrNiMoV or 30CrMnSiNi2A material.

The inner wall and the outer wall of the locking ring are provided with 4 through holes in a penetrating mode, and the through holes are arrayed and distributed uniformly around the longitudinal axis of the locking ring in a circumferential mode.

Wherein, the stopper is the crescent, and it has the through hole to open on the stopper, the screw from the stopper upper end pass the through hole with the screw hole of drawing first upper end makes stopper and drawing first threaded connection, the quantity of through hole has 3 and follows the crescent pitch arc direction evenly distributed of stopper.

The drawing head is provided with 2 inner circumferential walls, the inner circumferential walls are provided with threads, the two inner circumferential walls are in butt joint, an opening is formed from the upper end to the lower end of the drawing head after the inner circumferential walls are in butt joint, the included angle between the lower end and the upper end of the two open inner circumferential walls is 20 degrees, the external thread range of the drawing screw rod is M36 multiplied by 4-M56 multiplied by 5.5, and the internal thread range on the inner circumferential wall of the drawing head is Tr36 multiplied by 6-Tr 60 multiplied by 9.

The upper end of the valve seat puller acted by hydraulic pressure is provided with a drawing nut and the other end of the drawing screw rod is in threaded connection, the outer circumferential wall of the drawing nut is provided with a notch, the outer circumferential wall is also provided with a threaded hole, the number of the notches and the threaded holes is 4, the notches and the threaded holes are in annular arrays on the drawing nut, and the notches and the threaded holes are arranged in a crossed mode and form included angles of 45 degrees.

The locking ring is matched with the drawing head in a clearance fit mode through a base hole, and the locking ring and the drawing head are matched in a clearance fit mode

The utility model has the advantages as follows:

1. in stopper and the locking ring, the stopper is located the drawing head upper end, the stopper with draw the head upper end and pass through bolted connection, the locking ring is located the lateral wall of drawing the head, the inner wall of locking ring and the lateral wall contact cooperation of drawing the head, interior step has been seted up to the lower terminal surface of stopper, interior step is formed towards radial outside direction by the geometric centre of stopper, the upper end of interior step gland drawing the head, stopper and locking ring are guaranteed together that the drawing head can normal work and is let the lead screw carry out the screw precession that can be accurate in drawing the head upper end promptly, and the drawing head can open, can let and hang the screw thread (the box) of drawing the head screw thread (box) and pull rod lead screw and be in normal fit state all the time to effectively avoid screw thread root fracture or screw flank to bond, make the disk seat main part draw the operation more reliably, The safety is realized, the equipment maintenance operation efficiency is effectively improved, and the good operation of field equipment is ensured.

2. The internal diameter scope of locking ring is phi 50-100mm, and the external diameter scope is phi 65-120mm, and the high range is 20-50mm, and the material of locking ring is any one in 40CrNiMo, 45CrNiMoV or 30CrMnSiNi2A material, and the locking ring has excellent structural strength and rigidity, can guarantee to draw the screw rod and be in normal condition all the time with the screw-thread fit of drawing the head, prevents the abnormal conditions of thread slipping and thread gluing, improves the security and the reliability of operation.

3. The through-hole has been seted up in the interior outer wall of locking ring through, the through-hole number is 4, and the quality of locking ring can be reduced to the through-hole about the longitudinal axis circumference array and the evenly distributed of locking ring, avoids heavy locking ring assembly.

4. The stopper is crescent, and it has the through hole to open on the stopper, the screw from the stopper upper end pass the through hole with the screw hole of drawing first upper end makes stopper and drawing first threaded connection, the quantity of through hole has 3 and follows the crescent pitch arc direction evenly distributed of stopper, draws the lead screw and can be accurate in drawing first upper end and carries out the screw precession, effectively prescribes a limit to draw the lead screw not eccentric when being close to drawing first upper end, makes to draw the lead screw accuracy and inserts drawing first upper end, and the stopper can fasten in the upper end of drawing the head, guarantees that the disk seat puller operation is reliable.

5. The number of drawing head is 2, and the drawing head has the internal perisporium, two the internal perisporium butt joint, forms the opening form from the upper end of drawing head to the lower extreme after the internal perisporium butt joint, and the lower extreme that is two internal perisporium of opening form is 20 with the contained angle of upper end, and the drawing head upper end is radial to opening, and the drawing head lower extreme is radial to opening simultaneously, makes the barb upper surface on the drawing head and the lower surface cooperation area increase of disk seat main part.

6. The upper end of the ware is drawn to disk seat through the hydraulic pressure effect have draw the nut with the other end of drawing the lead screw carries out threaded connection, the outer circumferential wall of drawing the nut is opened jaggedly, threaded hole is still bored to the outer circumferential wall, the breach with the number of screw hole is 4, and breach and screw hole ring array on drawing the nut, breach and screw hole cross arrangement and contained angle are 45, conveniently draw the nut and dismantle from drawing the lead screw, cooperate the breach or through the rotatory dismantlement of screw rod cooperation screw hole through specialized tool.

7. The locking ring and the matching of the drawing head are clearance fit of a base hole, and the matching relation of the locking ring and the drawing head is that

The reliable combination of the locking ring and the outer wall of the drawing head is ensured, the locking ring locks and limits the radial opening of the drawing head when the drawing head opens in the radial direction, meanwhile, a gap is reserved between the locking ring and the drawing head to facilitate the tightness adjustment between the locking ring and the drawing head, and the thread (female buckle) of the drawing head and the thread (male buckle) of the pull rod lead screw are always in a normal matching state, so that the screw is effectively prevented from being screwedThe threaded tooth root is broken or the tooth surface of the thread is bonded or the thread is damaged or adhered, so that the valve seat drawing and pulling operation is more reliable and safer, the equipment maintenance operation efficiency is effectively improved, and the good operation of field equipment is ensured.

Drawings

FIG. 1 is a schematic view of a prior art structure of the present invention;

FIG. 2 is a schematic view of the bonding structure of the thread tooth surface of the present invention;

FIG. 3 is a schematic view of an improved structure of the present invention;

fig. 4 is a schematic view of the drawing nut in a top view direction;

FIG. 5 is a schematic view of the cross-sectional direction structure of the drawing nut of the present invention;

FIG. 6 is a schematic view of the drawing head structure of the present invention;

FIG. 7 is a schematic view of the sectional structure of the limiting block of the present invention;

fig. 8 is a schematic view of the top-view direction structure of the limiting block of the present invention;

figure 9 is a schematic cross-sectional view of a locking ring according to the present invention.

Reference numerals: the valve comprises a drawing nut 1, a notch 11, a threaded hole 12, a drawing hydraulic cylinder 2, a liquid inlet pipe 3, a valve box body 4, a valve seat main body 5, a drawing head 6, an inner peripheral wall 61, a barb 62, a drawing screw rod 7, a limiting block 8, an inner step 81, a locking ring 9 and a through hole 91.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

Example 1

As shown in fig. 1, a conventional hydraulically acting valve seat puller generally comprises the following main components: the hydraulic drawing device comprises a drawing nut 1, a drawing hydraulic cylinder 2, a liquid inlet pipe 3, a valve box body 4, a valve seat main body 5, a drawing head 6 and a drawing screw rod 7, wherein the drawing screw rod 7 is in threaded connection with the drawing head 6, the drawing nut 1 is in threaded connection with the drawing screw rod 7, liquid is injected through the liquid inlet pipe 3 through a hydraulic pump to form high pressure, a piston of the drawing hydraulic cylinder 2 drives the drawing screw rod 7 to move upwards, and a pulling force F1 for drawing the valve seat main body 5 is provided;

the drawing screw rod 7 is connected with the drawing head 6 at the lower end and connected with the drawing nut 1 at the upper end, and has the function of opening the drawing head 6 and driving the drawing head 6 to move upwards to draw out the valve seat main body 5;

the drawing head 6 is connected with the drawing screw rod 7, the drawing head 6 is opened to hook the lower end face of the valve seat main body 5 after the drawing screw rod 7 is screwed, and the valve seat main body 5 is hooked to move upwards under the driving of the drawing screw rod 7 to realize the function of drawing out the valve seat main body 5;

the drawing nut 1 is positioned on the piston of the drawing hydraulic cylinder 2 and connected with the drawing screw rod 7, and can drive the drawing screw rod 7 to move upwards.

Example 2

As shown in fig. 2, in the conventional hydraulically acting valve seat puller, the core component is the puller 6, the mainstream design of the structure of the puller 6 at present is a mode of using an anchor ear and a thread to open the puller 6, and the puller 6 with the anchor ear structure is a mode of using a pair of anchor ears to hoop the upper ends of the two puller 6, and in practical use, it is found that the puller 6 has a defect, and when the matching thread of the puller 6 is stressed, because a tendency of opening the anchor ear can be formed under the action of a radial component force F2 on the tooth surface of the thread, when the component force F2 is large enough, the elastic deformation of a coupling screw of the anchor ear can be caused, so that the increase of the actual inner diameter of the anchor ear cannot sufficiently ensure that the thread of the puller 6 is normally matched with the thread of the drawing screw rod 7. F1 is hydraulic drawing piston up force to overcome the interference force of valve seat to draw out valve seat, which can be controlled by hydraulic pump;

f2 ═ Tan (θ) equation (1)

Equation (2) for Sec (θ)

The failure of normal matching of the threads can easily lead to tooth root fracture (commonly called as slipping) of the threads, or the surface plastic deformation caused by overlarge contact stress of the surfaces of the threads leads to thread gluing, which can seriously affect the safety and smoothness of the pulling and maintenance operation of the valve seat main body 5 and bring non-negligible pressure to the maintenance operation and equipment operation management.

Through analysis, the root cause of the above problems is due to the defects of strength and rigidity of screw connection existing in the hoop type structure, when the valve seat main body 5 works for a long time or works under a high-pressure working condition, the interference force of the valve seat main body 5 is increased, and the component force of F2 is increased, because the hoop screw bears the stress σ:

σ ═ 0.5 × F2/a, where a is the effective cross-sectional area equation (3) for the screw

It can be seen from formula (3) that the larger F2 is, the larger stress σ is, which easily causes severe elastic deformation, plastic deformation or even breakage of the screw, resulting in abnormal thread matching state of the drawing screw rod 7 and the drawing head 6, resulting in corresponding thread damage and also easily reducing the working life of the thread. Theoretically, the problem can be solved by adopting the enlarged hoop connecting screw, but the enlarged hoop must be correspondingly enlarged, the volume of the drawing head is increased, and the improvement measure cannot be realized due to the limited size of the inner cavity of the valve box body 4.

Example 3

To solve the problems of embodiments 1 and 2, as shown in fig. 3, the valve seat puller of this embodiment includes a valve seat main body 5, a pulling head 6 and a pulling lead screw 7, an O-ring groove is formed on an outer side wall of the valve seat main body 5, the valve seat main body 1 is in a cone shape, the O-ring groove is located at a central position of an outer side wall of the valve seat main body 5, an O-ring is installed in the O-ring groove, one end of the pulling lead screw 7 is in threaded connection with an inner side of the pulling head 6, a barb 62 is formed at a lower end of the pulling head 6, an upper surface of the barb 62 is matched with a lower surface of the valve seat main body 5, the valve seat puller acting through hydraulic pressure further includes a limiting block 8 and a locking ring 9, the limiting block 8 is located at an upper end of the pulling head 3, the limiting block 8 is connected with an upper end of the pulling head 6 through a screw, the locking ring 9 is located at an outer side wall of the pulling head 6, the inner wall of the locking ring 9 is in contact fit with the outer side wall of the drawing head 6, an inner step 81 is arranged on the lower end face of the limiting block 8, and the inner step81 is formed by the geometric center of the limit block 8 towards the radial outward direction, the inner step 81 covers the upper end of the drawing head 6, the locking ring 9 is matched with the drawing head 6 in a base hole clearance fit mode, and the matching relation of the two is that

The inner diameter range of the locking ring 9 is phi 50-100mm, the outer diameter range is phi 65-120mm, the height range is 20-50mm, the material of the locking ring 9 is any one of 40CrNiMo, 45CrNiMoV or 30CrMnSiNi2A, the locking ring 9 and the drawing head 6 are matched, and the drawing head is locked by the locking ring 9 with high strength and rigidity aiming at the defects of the hoop structure drawing head 6. As shown in fig. 9, through holes 91 are formed through the inner and outer walls of the locking ring 9, the number of the through holes 91 is 4, and the through holes 91 are circumferentially arrayed and uniformly distributed about the longitudinal axis of the locking ring 9.

As shown in fig. 6, the number of the drawing heads 6 is 2, the drawing head 6 has an inner circumferential wall 61, the inner circumferential wall 61 has threads, two of the inner circumferential wall 61 is butted, the inner circumferential wall 61 is butted and then forms an opening shape from the upper end to the lower end of the drawing head 6, the included angle between the lower end and the upper end of the two inner circumferential walls 61 in the opening shape is 20 °, the upper end of the drawing head is radially expanded, and the lower end of the drawing head is radially expanded, so that the matching area between the upper surface of the barb on the drawing head and the lower surface of the valve seat body is increased.

As shown in fig. 7 and 8, stopper 8 is crescent, and it has through hole 82 to open on the stopper 8, the screw from stopper 8 upper end pass through hole 82 with the screw hole of drawing head 6 upper end makes

stopper

8 and 6 threaded connection of drawing head, the quantity of through hole 82 has 3 and follows stopper 8 crescent camber line direction evenly distributed.

As shown in fig. 4 and 5, the upper end of the valve seat puller acted by hydraulic pressure has a drawing nut 1 and the other end of the drawing screw rod 7 is in threaded connection, the outer circumferential wall of the drawing nut 1 is opened with a notch 11, the outer circumferential wall is drilled with a threaded hole 12, the notches 11 and the threaded holes 12 are 4 in number, the notches 11 and the threaded holes 12 are in annular array on the drawing nut 1, the notches 11 and the threaded holes 12 are arranged in a crossed manner and have included angles of 45 degrees, the nut is conveniently drawn and detached from the drawing screw rod, and the nut is matched with the notch through a special tool or is rotationally detached through a screw rod matched with the threaded holes.

Example 4

The utility model discloses a valve seat puller of hydraulic pressure effect provides some and experimental test data, the test of the biggest tensile force F1 that bears:

in the factory experiment, the maximum F1 power of 3 groups of valve seat pullers with novel locking ring 9 structures and 3 groups of hoop structure valve seat pullers was contrastingly tested, and the data are shown in the following table:

therefore, the novel locking ring 9 structure valve seat drawing device has the structural strength and rigidity far exceeding those of the hoop structure valve seat drawing device, and the work is safer and more reliable.

The main technical parameters of the valve seat puller with the novel locking ring structure are as follows:

the locking ring is matched with the drawing hook block

The inner diameter range of the locking ring is phi 50-100 mm; the outer diameter range is phi 65-120 mm; the height ranges from 20 to 50 mm.

The external thread range of the drawing screw rod 7 and the internal thread application range of the drawing head 6 are as follows:

M36X 4-M56X 5.5; tr36 x 6-Tr 60 x 9 ensures that the thread matching of the drawing screw rod and the drawing head is always in a normal state, prevents the abnormal conditions of the slide fastener and the thread gluing, and improves the safety and the reliability of the operation.

The mechanical performance requirements of the locking ring, the drawing screw rod and the drawing head are as follows:

the tensile strength delta b is more than or equal to 900MPa, and the yield strength delta s is more than or equal to 800 MPa.

Example 5

Embodiment 5 differs from embodiment 1 in that the working principle of embodiment 5 is as shown in fig. 3: the drawing screw rod 7 can be inserted into the upper end of the drawing head 6 through the limiting block 8 at the upper end of the drawing head 6 to ensure that the lower end of the drawing screw rod 7 is not eccentric, and the upper end of the drawing head 6 is radially opened; rotating the drawing screw rod 7 to push the barb 62 at the lower end of the drawing head 6 downwards to extrude the upper end of the valve seat main body 5, deforming the middle part of the drawing head 6, and continuing to push until the upper surface of the barb 62 is matched with the lower surface of the valve seat main body 5; draw the opening form position middle position that internal perisporium 61 formed when the lower extreme of lead screw 7 inserts the middle-end of drawing head 6 promptly, to drawing lead screw 7 upper end and letting in liquid, draw lead screw 7 lower extreme inflation and insert the middle-end opening form position screw-thread fit of drawing head 6, two draw head 6 middle-end radial movement open, open the lateral wall contact of drawing head (6) locking ring (9) inner wall is often, locking ring 9 restriction drawing head 6 middle-end radial movement opens, barb 62 upper surface that the lower extreme of drawing head 6 has and valve seat main part 5's lower surface cooperation area increase, draw hydraulic cylinder 2 promotion drawing nut 1 and make to draw lead screw 7 rebound drive valve seat main part 5 to move up.

Claims

1. The utility model provides a ware is drawn to disk seat of hydraulic pressure effect, includes disk seat main part (5), draws head (6) and draws lead screw (7), lateral wall on the disk seat main part (5) is provided with O circle groove, and disk seat main part (5) are the cone type, O circle groove is located the central point of disk seat main part (5) lateral wall and puts, and O circle inslot is installed O type circle, draw the one end of lead screw (7) with draw the inboard threaded connection of head (6), the lower extreme of drawing head (6) is formed with barb (62), the upper surface of barb (62) and the lower surface cooperation of disk seat main part (5), its characterized in that: the ware is drawn to disk seat of hydraulic pressure effect still includes stopper (8) and locking ring (9), stopper (8) are located the upper end of drawing head (6), stopper (8) with draw head (6) upper end through screwed connection, locking ring (9) are located the lateral wall of drawing head (6), the inner wall of locking ring (9) and the lateral wall contact cooperation of drawing head (6), interior step (81) have been seted up to the lower terminal surface of stopper (8), interior step (81) are formed by the geometric center radial outside direction of orientation of stopper (8), the upper end of interior step (81) gland drawing head (6).

2. A hydraulically acting valve seat puller as claimed in claim 1, wherein: the inner diameter range of the locking ring (9) is phi 50-100mm, the outer diameter range is phi 65-120mm, the height range is 20-50mm, and the material of the locking ring (9) is any one of 40CrNiMo, 45CrNiMoV or 30CrMnSiNi2A material.

3. A hydraulically acting valve seat puller as claimed in claim 2, wherein: the inner wall and the outer wall of the locking ring (9) are provided with through holes (91) in a penetrating mode, the number of the through holes (91) is 4, and the through holes (91) are circumferentially arrayed and evenly distributed around the longitudinal axis of the locking ring (9).

4. A hydraulically acting valve seat puller as claimed in claim 1, wherein: stopper (8) are the crescent, and it has through hole (82) to open on stopper (8), the screw from stopper (8) upper end pass through hole (82) with the screw hole of drawing head (6) upper end makes stopper (8) and drawing head (6) threaded connection, the quantity of through hole (82) has 3 and follows the crescent pitch arc direction evenly distributed of stopper (8).

5. A hydraulically acting valve seat puller as claimed in claim 1, wherein: the number of drawing head (6) is 2, and drawing head (6) have interior perisporium (61), interior perisporium (61) have the screw thread, two interior perisporium (61) butt joint forms the opening form from the upper end to the lower extreme of drawing head (6) after interior perisporium (61) butt joint, and the lower extreme and the contained angle of upper end of two interior perisporium (61) that are the opening form are 20, the external screw thread scope of drawing lead screw (7) is M36 x 4-M56 x 5.5, the internal thread scope on the interior perisporium (61) of drawing head (6) is Tr36 x 6-Tr 60 x 9.

6. A hydraulically acting valve seat puller as claimed in claim 1, wherein: the upper end of the valve seat puller is provided with a drawing nut (1) and the other end of the drawing screw rod (7) is in threaded connection, the outer circumferential wall of the drawing nut (1) is provided with a notch (11), the outer circumferential wall is also provided with a threaded hole (12), the number of the threaded hole (12) is 4, the notch (11) and the threaded hole (12) are in annular array on the drawing nut (1), and the notch (11) and the threaded hole (12) are in cross arrangement and have an included angle of 45 degrees.

7. A hydraulically acting valve seat puller as claimed in claim 1, wherein: the locking ring (9) is matched with the drawing head (6) in a clearance fit mode through a base hole, and the matching relation of the locking ring and the drawing head is H9/f 9.