RU2242665C2 - Device for trenchless pipeline replacement - Google Patents

Abstract

FIELD: building, particularly for laying and replacing underground pipelines.

SUBSTANCE: device has hood with cutting blades, expander with bush for replacing tube connection and air-operated percussion machine. Percussion machine has body, nut located from rear body end, anvil arranged from front body end, air-feeding pipe, hollow hammer having through channel cooperating with air-feeding pipe, idle chamber arranged from anvil side, working stroke chamber and outlet channels formed in the body. Outlet channels are made in side body wall and extend in radial direction. Outlet channel is defined by annular gap between body and replacing tube. Working stroke chamber is located in the body from nut side. Installed in body from nut side is lid with central orifice. Prechamber for line air is formed between lid and hut. Air-feeding line is arranged in central lid orifice with annular gap establishing permanent connection between working stroke chamber and prechamber.

EFFECT: increased impact power.

3 cl, 1 dwg

Description

The invention relates to the field of construction equipment and relates to pneumatic shock devices used to form wells in the ground for trenchless laying and replacement of pipelines.

A pneumatic impact device is known (see, for example: RF patent No. 2063328, MKI B 25 D 17/24, 07/10/1996), comprising a housing with a cavity on the side of the rear end of the housing, a drummer with a through cavity and a channel, a step air distribution a tube installed at one end in the nut of the rear end of the housing and the opposite end with a step into the through cavity and channel in the hammer. The drummer divides the housing cavity into the idle chamber from the front end side, the working chamber in the drum cavity and the low-pressure annular chamber from the side of the nut of the rear end of the housing (atmospheric) air, communicated through exhaust ports in the nut with the space of the borehole channel. The exhaust air is exhausted from the idle chamber through a radial channel in the wall of the hammer into the exhaust annular chamber and through the exhaust windows of the nut into the borehole.

The air is released into the idle chamber from the network by means of a stepped portion of the air distribution tube when interacting with the cut-off edges of the radial channel in the hammer.

The disadvantage of this device is the lack of impact power due to the design of the exhaust annular chamber from the side of the nut of the rear end of the housing, because in this case, the annular working area of the striker from the side of the exhaust chamber is not loaded with excess air pressure from the network and the power impulse of acceleration of the striker during the working stroke is not formed in it.

Also known is a pneumatic shock device used as a mover of a device for trenchless replacement of obsolete drainage pipelines with new ones (see, for example: RF patent No. 2173254, Mcl B 25 D 9/04, 9/08, 17/24, 2001), comprising a housing in which a striker is arranged with the possibility of reciprocating movement, forming a striking chamber for the reverse motion of the striker with the housing. The drummer is made with an axial cavity and radial windows. In the axial cavity of the striker there is a large step of a stepped air distributor, a smaller step of which is fixed in the rear end of the housing. At the rear end of the housing exhaust windows are made. The large stage of the air distributor has two edges on the outer surface. In the drummer, a through axial channel is made. In the front of the housing is made through an axial channel. A cap is attached to the bow of the housing. On the outer surface of the housing in its front part a conical surface is made for fixing the nozzles necessary for performing certain types of work.

The device is adapted for trenchless replacement of underground pipelines. A nozzle is installed on the conical surface of the body to destroy the old pipeline. The duct is attached to the bow or tail of the housing.

The specified device for trenchless replacement of drainage pipelines adopted as a prototype, as containing the largest number of essential features used in the proposed technical solution.

The disadvantage of the prototype is a constructive solution for the air exhaust path that has been exhausted in the idle chamber: longitudinal channels — grooves and a recess on the striker, a radial channel in the wall of the striker, an annular channel formed by the tube and the internal cavity of the striker, an exhaust annular chamber in the housing, and exhaust windows in the nut the rear end of the housing with access to the channel formed by the inner surface of the replacement pipe, which form a complex lingering exhaust channel with significant total resistance, causing an increase s time release process, reducing the impact frequency and impact power of the machine.

The disadvantage of the prototype is also the design of the exhaust annular chamber from the side of the nut of the rear end of the housing, which causes, when idling, counterpressure in it and braking of the striker, leading to a decrease in its stroke, and hence the acceleration section during the working stroke. In addition to the aforementioned, low air pressure from the side of the exhaust annular chamber, since it does not communicate with the compressed air network, and therefore it is not possible on its side to use the annular area of the projectile under pressure to generate a power impulse during the working stroke, which in turn reduces the impact power of the machine .

The noted drawbacks generally reduce the productivity of sinking when replacing the pipeline.

The technical problem solved by the invention is to increase the impact power and productivity of the sinking when replacing the drainage pipeline trenchless method.

The problem is solved in that the device for trenchless pipe replacement, containing a cap with cutting knives, an expander with a sleeve for attaching a replacement pipe, a pneumatic impact machine, consisting of a housing, a nut from the rear end of the housing, anvil from the front of the housing, air supply tube, hollow with the through channel of the striker interacting with the air supply tube, idle chamber from the anvil side, the working chamber, exhaust channels in the housing, m radial outlet passages formed in the side wall of the housing, and the outlet chamber is formed by an annular gap between the housing and the replacement pipe and the working stroke chamber placed in the housing by the nut.

It is advisable to install a cover with a central hole in the housing on the nut side and to form a pre-chamber of the supply air between the cover and the nut.

It is advisable to install the air supply tube in the central hole of the lid with an annular gap constantly connecting the working chamber and the pre-chamber of the network air to each other.

The invention is illustrated in the drawing, which shows a section through a replacement pipe with a partial longitudinal section through a pneumatic impact machine in the process of destruction of the replaced pipe with simultaneous pulling of the device.

A device for trenchless replacement of pipelines contains a traction rope 1, a cap 2 with cutting knives 3, an expander 4 with a sleeve 5 for attaching a replacement pipe 6, a pneumatic impact machine, consisting of a housing 7 with a nut 8 from the side of the rear end of the housing, anvil 9 from the side its front end, the air supply tube 10 with a shoulder 11 and a through channel 12 in the tube, a hollow hammer 13 with a through central channel 14, interacting with the tube. The drummer 13 divides the internal cavity of the housing into the idle chamber 15 and the working chamber 16. Radial outlet channels 17 and 18 are made in the side wall of the casing, and on the side of the rear wall of the casing there is a lid 19 with a central hole 20, in which a tube is mounted, which rests on the annular area of the mouth of the central opening of the lid. Between the nut and the cover, a pre-chamber 21 of the network air is formed, which enters through the air supply flexible sleeve 22 to the pre-chamber. The central hole 20 and the side surface of the tube 10 form an annular gap by which the pre-chamber of the air supply and the working chamber are constantly communicated with each other. An annular gap provides radial and axial movement of the tube in the opening of the lid. Between the loaded surface 23 of the housing and the inner surface 24 of the replacement pipe 6, a flow-through annular chamber 25 for discharging air exhausted in the chambers 15 and 16 is formed. The replacement pipe 6 is fixed relative to the sleeve by any known device 26, for example, a bolt one. Destructible pipe 27 is a guide for the moving device.

Pneumatic impact machine device for trenchless pipe replacement works as follows. When compressed air is supplied from the compressor through an air-supplying flexible hose, it enters the network air chamber 21. From the chamber 21, the network air enters the working chamber 16 through an annular exhaust throttle channel 20 formed by a gap between the side surface of the tube 10 and the side surface of the central hole of the cover 19 through flats, grooves, and the like. in the flange 11. At the same time, the network air from the chamber 21 enters the idle chamber 15 through the inlet throttle channel 12 in the tube 10, the through central channel 14 in the hammer 13 and the gap between the contact surfaces of the hammer and the anvil shank 9.

The air pressure in the chamber 16 will remain almost equal to atmospheric, since the exhaust channel 18, having a passage section area significantly exceeding the passage section area of the annular inlet throttle channel formed by the gap between the surface of the central hole 20 of the cover 19 and the tube 10, is open. Thus, through the channel 18 in the housing 7, the chamber 16 communicates with the flow-through annular chamber 25 exhaust formed by the lateral outer surface 23 of the housing and the inner surface 24 of the replacement pipe 6 and then through the pipe with the atmosphere.

In the chamber 15, the air pressure increases, and the striker 13 will begin to move along the tube 10 from the shank of the anvil 9, making idle.

Upon subsequent movement, the hammer 13 will block the outlet channel 18 with its lateral surface, as a result of which the pressure of the air cut off in the chamber 16 and the air flowing back into this chamber through the annular hole 20 will begin. Continuing the movement, the hammer 13 will open the exhaust channel 17, and then the channel 18, as a result of which the air pressure in the idle chamber 15 and in the annular exhaust chamber 25 will decrease to atmospheric pressure, despite the flow of air into the idle chamber through the through channel 12 in the tube 10 from the chamber 21, as the orifice passage 12 substantially smaller than the flow section channels 17 and 18 release. Thus, the exhaust air from the chamber 15 is discharged into the annular chamber 25 and further through the pipe 6 into the atmosphere.

As the drummer 13 idles, the air pressure in the chamber 16 of the stroke will increase. Under the pressure of the difference between the pulses of the air pressures in the chambers 16 and 15, the hammer 13 will slow down its movement and stop in the calculated position. Immediately under the pressure of the pressure pulse from the side of the chamber 16, the striker 13 will begin to move rapidly along the tube 19 towards the shank of the anvil 9, making a working stroke.

As the striker 13 moves, the air pressure in the chamber 16 will decrease. This is due to the fact that the rapidly increasing volume of the chamber 16 during the working stroke does not have time to fill with the network air coming from the chamber 21 through the annular channel formed by the hole 20 and the tube 10. However, the air pressure in the chamber 16 will be maintained by the calculated one.

With further movement of the striker 13, its lateral surface will block the channel 18, and then the channel 17, after which the compression of the air cut off in it and the air of the network again coming from the chamber 21 through the channel 12 in the tube 10 will begin in the chamber 15.

After the side surface of the striker 13 opens the channel 18 for discharging air pressure in the working stroke chamber 16, it will drop sharply to the level of air pressure in the annular chamber 25 for discharging and then to atmospheric pressure, since the discharge chamber is communicated by the channel in the replacement pipe 6 to the atmosphere.

Overcoming the air backpressure impulse from the side of the idle chamber 15, the hammer 13 under the influence of the difference of pressure pulses from the side of the chambers 16 and 15 and the pulse acquired by the hammer during acceleration, strikes the anvil shank 9, and the described working process of the pneumatic impact machine will be repeated with the only difference is that the subsequent idle will also be formed with the participation of the pulse of the rebound of the striker from the shank of the anvil.

The proposed constructive solution ensures the constancy of the annular section formed by the gap between the central hole 20 in the fixed cover 19 and the side surface of the tube 10, since regardless of the position of the tube 10 in the central hole of the cover, their diametrical sections are constant, and the geometric area of the gap is determined by the difference in the cross-sectional areas of the tube and cover holes.

The implementation of the air supply tube of the same cross-section allows you to maximize the use of the working platforms of the drummer from the side of the lid and anvil in the working process.

The exhaust channels 17 and 18 in the wall of the housing 7 create minimal local resistance at the outlet of the treated air from the chambers 15 and 16, and the use of an annular chamber 25, an exhaust formed by the outer side surface of the housing 7 and the inner side surface of the replacement pipe 6, allows the pipe to be centered relative to housing than to ensure a uniform gap between them and a uniform load on the site of the replacement pipe and its fastening elements relative to the coupling, as well as less “yaw” of the cap in the replaced t rub, i.e. destroy it productively, followed by compaction of individual pieces in the side walls of the soil of a new well.

The installation of the cover 19 from the side of the nut 8 between the chamber 21 of the network air and the chamber 16 of the working stroke allows you to create a receiver of network air and evenly distribute it between the chambers 15 and 16 without reducing the diametrical area of the cross-section of the volume of the chambers and the working area of the drummer from the side of a chamber provides reliability of the formation of power pulses from their sides and increase the energy parameters of the device for trenchless replacement of pipelines.

Claims (3)

1. A device for trenchless pipe replacement, comprising a cap with cutting knives, an expander with a sleeve for attaching a replacement pipe, a pneumatic impact machine consisting of a body, a nut from the side of the rear end of the body, an anvil from the front end of the body, an air supply tube, hollow through the channel of the striker interacting with the air supply tube, the idle chamber on the anvil side, the working chamber, exhaust channels in the housing, characterized in that the exhaust channels are radial in the side wall of the housing, the exhaust chamber is formed by an annular gap between the housing and the replacement pipe, and the working chamber is placed in the housing on the nut side. 2. The device according to claim 1, characterized in that a cover with a central hole is installed in the housing on the side of the nut and a pre-chamber of mains air is formed between the cover and the nut. 3. The device according to claim 1 or 2, characterized in that the air supply tube is installed in the Central hole of the cover with an annular gap that constantly connects the working chamber and the pre-chamber of the network air to each other.