RU2244072C2 - Method for actuation of pneumatic percussion mechanism and device for its realization - Google Patents

Abstract

FIELD: construction, applicable for trenchless laying and replacement of underground pipe-lines.

SUBSTANCE: a reciprocating striker is positioned in the casing of the pneumatic percussion mechanism. The air-distributing system of the mechanism includes the front and rear working chambers, inlet and exhaust valves and a fixture for closing and opening of the exhaust channels made in the form of a spring-loaded end face stopper coupled to a tractive member. At actuation of the pneumatic percussion mechanism, before the supply of compressed air, the exhaust channels are closed, they are opened after the inner cavities of the pneumatic percussion mechanism are filled with compressed air.

EFFECT: provided automatic cyclic action of the pneumatic percussion mechanism.

3 cl, 3 dwg

Description

The present invention relates to the field of construction equipment and relates to methods and devices for trenchless laying and replacement of underground pipelines.

A known method of starting a pneumatic impact device described in A.S. 924276, including the supply of compressed air through an air supply hose from the line into the device. Compressed air acts on the starting valve and, when the pressure reaches the nominal value, it opens, compressed air enters the working chambers and starts the firing pin. During operation, the valve is open due to exposure to compressed air. In the event of a decrease in pressure or disconnection of the device from the line, the valve is displaced by the spring to its original position and the device stops. The device consists of a housing placed in it with the possibility of reciprocating movement of the striker, air distributor, rear nut with exhaust channels for passing exhaust air. In a smaller stage of the air distributor, a spring-loaded start valve is installed.

The disadvantage of this method and device is its low reliability. When the pressure drops below a certain limit or the line is turned off, the machine stops, due to the fact that one of the valve positions is "openly" fixed by the pressure of the compressed air supplied to the device. As a result, there is a great chance of losing the mechanism or carrying out a large amount of earthwork to extract it.

There is a method of starting up a pneumatic impact device, known from the certificate for utility model No. 13219, which also includes the use of a start valve, also triggered by the main pressure of compressed air. The device comprises a hollow body with a drummer located therein, which reciprocates under the action of compressed air, an air distributor that alternately delivers compressed air to one or another chamber, a start valve and a rear nut with exhaust channels for exhaust air passage located at its lower stage . The valve is powered by compressed air supplied from the air supply line. Its design is made of a two-stage sleeve mounted on the air distributor by means of a spring, covering the two-stage part of the smaller stage of the air distributor with through transverse channels in its steps and a partition between the transverse channels. This design allows for stable operation of the device in the case of minor (about 2 MPa) pressure fluctuations in the network (hereinafter, we mean not absolute but overpressure).

The technical problem solved by this invention is to increase the reliability of starting the device even in extreme situations.

The problem is solved in that when starting up a pneumatic impact device for laying and replacing underground pipelines, including supplying compressed air through the air duct and exhausting exhaust air through the exhaust channels, the exhaust channels are closed before the compressed air is supplied, which open after filling the internal cavities with compressed air devices. This order of operations allows you to directly start the device - to cause the movement of the drummer - at the moment when the working chambers are already filled with compressed air, you just have to open the exhaust channels. Start-up of the device can be ensured even with a large length of air supply hoses (more than 100 m) and a pressure in the line less than nominal.

It is advisable to open the exhaust channels by mechanical means, for example by means of a cable. This allows for forced fixation of the opening and closing of channels, regardless of the pressure in the network, which increases the reliability of the launch and the preservation of the operating mode. It also allows the use of a winch and the transfer of significant effort at virtually any distance from the working pits.

It is advisable to implement this method to use a pneumatic shock device for laying and replacing underground pipelines, including a hollow body, a drummer with a reciprocating movement, an air distribution system with inlet and exhaust channels, and provide it with a means for closing and opening the exhaust channels, made , for example, in the form of a spring-loaded end plug connected to the traction body. This will allow simple structural means to guarantee the operation of opening and closing windows regardless of the remoteness of the device from the input and output pits and from changes in pressure in the pneumatic line.

The invention is illustrated by the following drawings:

Figure 1 presents a diagram of a device.

Figure 2 - device with exhaust forward in operation.

Figure 3 - device with exhaust back to work.

The method is implemented as follows.

The device 1 is installed in the inlet pit (not shown) and its front part is connected by a cable 2 with a traction body (not shown). The cable 2 is pre-passed through the old pipe 3 or a pre-formed leader well. Behind the device 1, a new pipe 4 is connected, into which an air supply hose 5 is connected, connected to a compressor (not shown). When compressed air is supplied to the device, the exhaust channel 6, which is directed towards the well penetration (Fig. 1), is closed by an end cap 8, equipped with a spring 7, which is connected to the cable 2, so the cavities of the device are filled with compressed air. When filling the working chambers 11 and 12 with compressed air, the striker 10 slowly moves from the position shown in Fig. 1 to the rear position (Fig. 2) due to the fact that the working area of the striker 10 from the side of the chamber 11 is larger than from the side of the chamber 12, and opens the exhaust channel 9. But since channel 6 is closed, the exhaust does not occur, the device does not start up. Then, by tensioning the cable 2, the spring 7 is compressed and, through the end cap 8, the exhaust channel 6 is sharply opened. the channel 9 is open, there is an exhaust from the chamber 11, the drummer 10 is accelerated by the air pressure in the chamber 12 and strikes the front of the device 1. Before the impact in the hammer 10, the windows 13 open and the inlet to the chamber 11 occurs. Next, the cycle repeats.

Under the action of impacts, the housing 1 of the device moves forward, destroys the old pipe 3, presses its remains into the soil, forms a well in it and draws a new pipe 4 connected to the tail end into it.

In the case when the device is made with an exhaust channel 6 located at the rear of the device (Fig. 3), an end cap 8, equipped with a spring 7 and connected to the cable 15, closes the channel 6. When air is slowly supplied through the channels 13, 14 slowly the chambers 12, 11 and (by the gaps) the chamber 17 are filled. Due to the fact that the forces of all three chambers act on the drummer 10, the movement of the drummer 10 does not occur. After tensioning the cable 15 compresses the spring 7, the plug 8 opens the channel 6. There is a sharp exhaust of compressed air from the chamber 17 through channels 6 and 16 into the atmosphere. Now, efforts are exerted on the firing pin 10 only from the side of the chambers 11 and 12. Since the working area from the side of the chamber 11 is larger than from the side of the camera 12, the firing pin 10 starts to move sharply backward until the channels 13 connect the camera 11 to the camera 17. Compressed air from the chambers 11 and 17 through the channels 6 and 16 is released into the atmosphere. The pressure in the chamber 12, the drummer 10 first stops in the rear position, and then accelerates forward and strikes the housing 1 of the device. Shortly before the impact, the channels 13 connect the chambers 11 and 12. Next, the cycle repeats. Under the action of shock, the device moves, destroying the old pipe 3 and tightening the new 4.

Using the proposed method and device for its implementation allows the use of pneumatic devices for laying and replacing pipelines in soils with a significant length of the well without performing intermediate pits. It also becomes possible to make trenchless laying and replacement of underground pipelines in those cases when the laid or replacement pipe is pre-welded into a length of 100–200 m long. In this case, it is required to ensure reliable start-up of the device with a long length of the air supply hose.

Using a device with front or rear exhaust allows you to use this method when laying water pipes of almost any diameter and length.

Claims (3)

1. A method of starting up a pneumatic impact device for trenchless laying and replacing underground pipelines, comprising supplying compressed air to the device through an air duct and exhausting exhaust air through exhaust channels, characterized in that the exhaust channels are closed before compressed air is supplied, which open after filling with compressed air of internal cavities of a pneumatic impact device. 2. The method according to claim 1, characterized in that the opening of the exhaust channels is produced by mechanical means, for example by means of a cable. 3. The pneumatic impact device for laying and replacing underground pipelines according to claim 1, including a hollow body, a drummer arranged therein with the possibility of reciprocating movement, an air distribution system including front and rear working chambers, inlet and exhaust channels, characterized in that it equipped with a means for closing and opening the exhaust channels, made, for example, in the form of a spring-loaded end plug connected to the traction body.

Images