RU2090730C1 - Downhole pneumatic percussion mechanism - Google Patents

Abstract

FIELD: mining machinery, in particular, valveless downhole pneumatic percussion mechanism of closed type applicable in hole drilling in rocks of mean and high hardness. SUBSTANCE: use of split bushing embracing neck of hammer which are located in sleeve and installed in body in combination allows formation of circular and end chambers of working stroke providing increased working area of hammer in working stroke which is larger than the sectional area of body hollow and serves as base for provision of high energy parameters. Formed between working chambers is idle stroke chamber which is connected by means of channel with supplying channel and constantly being under pressure and capable of moving the hammer in idle stroke for considerable value providing for large working stroke to increase possibility of expansion of compressed air and to increase energy of single impact. There is no exhaust from idle stroke chamber to atmosphere to avoid unproductive consumption of compressed air occurring in emptying of parasite volumes which are always present in chambers. EFFECT: higher efficiency. 1 dwg

Description

 The alleged invention relates to the field of mining machines, and specifically to submersible pneumatic percussion mechanisms for drilling wells in rocks of medium and high strength and can find application in construction.

 Known pneumatic hammer described in [1] It has an idle chamber, constantly connected to the supply line. In the hammer, exhaust is carried out only from the travel chamber. Idling along its entire length, carried out by compressed air at network pressure, provides a significant stroke of the hammer and allows you to have an economical duty cycle due to the absence of emptied parasitic volumes in such a system in the idling chamber. However, during operation, such an idle chamber requires significant energy to overcome its resistance. In this design, the area of the striker working on a forward stroke is not large, and in the case of using this scheme for submersible hammers, this area will be even more limited due to the channels of the supply line to the idle chamber, which does not allow a large shock power.

 The closest analogue adopted for the prototype is a multi-chamber submersible pneumatic percussion mechanism described in [2]. This is a pneumatic hammer having a body, sleeve, hammer with necks covered by split sleeves, a crown mounted in the housing socket. It has end and ring chambers of idle and working stroke, due to which significant areas of working and idling of the drummer are created, the basis for increasing power in this machine. The area idling the drummer is large and equal to the area working idle, which allows for intensive movement of the drummer idling, reducing idle time, which positively affects power. However, in this case, in order to avoid a lot of resistance from the idling chambers on the move, the intake time into these chambers before the impact must be strictly limited and the necessary initial volumes must be available. The volume of the supply channels to the idling chambers in this design is also included in the initial volumes. All this determines a sufficiently large air flow rate for idling, reduces efficiency. A large number of idling chambers, requiring sufficient isolation, makes it necessary to have a large number of seating surfaces on the hammer parts, which complicates the design.

 The technical problem solved in the proposed invention is to increase efficiency and simplify the design. The problem is solved in that a sleeve is made in the sleeve that permanently connects the idle annular chamber to the supply channel, and a window in the sleeve through which the end and annular work chamber communicates is configured to periodically communicate between these chambers with the last idle annular chamber , while in the wall of the housing is made an annular bore with the possibility of periodically placing in it the cut-off edge of the head of the drummer and communication between the annular chamber of the worker a probe with a cavity between the drummer and the crown, and the channels in the crown are made open into the cavity and constantly connect it to the atmosphere.

 In the inventive hammer, the return stroke is carried out due to compressed air acting from the side of the annular reverse chamber, constantly connected to the supply line. The drummer has a relatively small working area on the side of this chamber, but due to the constant main pressure, a large casting of the drummer is possible, providing a large stroke during the working stroke, which determines the high energy of a single impact. There is no exhaust to the atmosphere from this chamber, but an inlet into the working chamber at the end of idle.

 Such a system allows to save compressed air due to the absence of parasitic volumes in the idle chamber, throughout its entire length it is necessary to overcome the resistance from the side of the annular idle chamber and the working chambers inevitably have initial volumes, such as channel volumes, air bag volume, but in general in the hammer, they are reduced, since the number of chambers in which they are located is reduced. And in the end, the amount of air spent on the return of the striker will be less than with the use of reverse cameras with exhaust to the atmosphere. To overcome the resistance during the stroke, the magnitude of the working area of the striker is of great importance. Using a split sleeve allows you to have a working area on the move greater than the cross-sectional area of the body cavity, which allows you to easily overcome the resistance from the side of the idle annular chamber having a small working area and to provide high energy parameters of the hammer. The cavity formed between the crown and the hammer does not require sealing. This simplifies the design of hammer parts.

 The exhaust system through this cavity allows you to get a large cross section of the exhaust line, to provide greater direct flow, which improves the emptying of the working chambers, reducing the resistance to movement of the drummer at idle.

 The drawing shows a longitudinal section of a submersible pneumatic impact mechanism.

 The mechanism comprises a housing 1, a hammer 2, having a head 3 with a cut-off edge 4 and a shank 5 with a cut-off edge 6. The head 3 and the shank 5 are connected by a neck 7. In the housing 1 there is a sleeve 8, covering the shank 5 and forming from its end face the end-face travel chamber 9. Inside the sleeve 8 is installed a split sleeve 10, covering the neck 7 of the hammer 2 and forming between it and the shank 5 an annular chamber of idle 11, and between it and the head 3 an annular chamber of the stroke 12. The half rings of the split sleeve 10 are fixed by the sides 13. Chambers 9 and 12 s They are connected by a channel 14 located in the sleeve 8, having a window 15 configured to interact with the cut-off edge 6 of the shank 5. There is a feed channel 16, and a channel 17 located in the sleeve 8 connects this channel 16 to the idle ring chamber 11. In the wall of the housing 1, an annular bore 18 is made with the possibility of interaction with the cut-off edge 4 of the head 3. In the socket of the housing 1, a drill bit 19 with channels 20 is movably mounted. The crown 19 forms a cavity 21 between it and the hammer 2. The channels 20 of the crown 19 are constantly open in the cavity 21.

 Works submersible pneumatic impact mechanism as follows.

 From the stand of the rods, compressed air is supplied to the supply channel 16, from where through the channel 17 in the sleeve 8 it enters the idle ring chamber 11. Acting on the working area of the hammer 2 from the side of this chamber, the compressed air drives the hammer 2. In the ring chamber 11, compressed air also acts on the split sleeve 10, covering the neck 7 of the hammer 2. However, it is stationary, since the stoppers 13 impede its movement. When the hammer moves, the head 3 with a cut-off edge 4 cuts off the annular bore 18 in the wall of the housing 1, isolating the the Central chamber of the working stroke 12 and the associated end chamber of the working path 9. Subsequently, the cut-off edge 6 of the shank 5 opens the window 15, communicating it with the annular chamber of idling 11. From the annular chamber of idling 11 connected to the supply channel 16, compressed air through the window 15, the channel 14 enters the end chamber of the working path 9 and the annular chamber of the working path 12. Due to the fact that the working area of the hammer from the side of the working paths due to the use of the split sleeve 10 is large (it is larger than the cross-sectional area of the core cavity 1 and whisker significantly greater working area from idling annular chamber 11) the striker 2, under the action of compressed air acting on the working areas, drastically decelerated and transferred to the working stroke. When the striker 2 is in motion, the cut-off edge 6 disconnects the window 15 from the annular idle chamber 11, stopping the inlet into the chambers of the stroke 9 and 12. In the future, the movement of the striker is carried out due to inertia and due to the expansion of compressed air.

 A significant size of the working area of the striker 2 from the side of the chambers of the stroke allows braking of the striker at a later intake of compressed air, and this predetermines, according to the valveless air distribution pattern, an earlier cut-off of the intake during the working stroke, allows more fully use the expansion of compressed air, as well increasing profitability. The increased area makes it easy to overcome the resistance from the side of the pressurized annular idle chamber 11.

 With further movement of the striker 2, the cutoff edge 4 of the head 3 opens the annular bore 18, the exhaust starts from the annular chamber of the working stroke 12 and from the end chamber of the working stroke 9 connected to it. In this case, air is ejected along the annular bore 18 into the cavity 21 and then through constantly open channels 20 of the crown 19, to the bottom of the well. At the end of the stroke, hammer 2 strikes the shank of crown 19. The cycle repeats.

 Due to the lack of exhaust into the atmosphere from the annular chamber of idling 11, it is possible to avoid unproductive air flow arising from the emptying of various parasitic volumes, and due to the significant area of the striker 2, high energy parameters are provided on the move.

 The ability to not seal the intermediate cavity 21 simplifies the design of the mechanism.

Claims (1)

 A submersible pneumatic percussion mechanism comprising a housing, a hammer, having a head and a shank, connected by a neck and having cut-off edges, a sleeve covering the shank and forming an end stroke chamber with its end face, a split sleeve covering the neck of the striker with the formation respectively between the sleeve and the shank, the sleeve and the drummer head of the idle and working stroke annular chambers, the last of which is permanently connected to the working chamber through the channel and the window in the sleeve by the feed chamber, the feed channel a crown with channels installed in the housing socket with the formation of a cavity between the crown and the end face of the striker, characterized in that a sleeve is made in the sleeve that constantly connects the idle annular chamber to the supply channel, and a window in the sleeve through which the end and annular working chamber communicate made with the possibility of periodic communication between each other of these chambers with an annular chamber of idling when opening the window with the edge of the shank of the hammer during idling of the latter, while in the wall of whisker annular recess is formed to periodically receiving the cut-off edge of the head impactor and communication between a working stroke chamber with an annular cavity between the hammer and the crown, wherein the channels in the crown are made open in a cavity and permanently connect it to the atmosphere.