RU2499876C1 - Device for additional sealing of coupling and conical threaded tube connections - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device for additional sealing of coupling and conical threaded tube connections includes a heating element, for example an inductor of annular type, a thermocouple, an amplifier of thermoelectromotive force occurring in the thermocouple. Besides, it includes a relay, via the winding of which the current flows, which is determined by thermoelectromotive force of the thermocouple, an energy source for the inductor and a timer. With that, the relay disconnects the inductor electric power supply line at achievement of temperature of brazing alloy full melting in the brazing zone. The timer disconnects the second line after lapse of brazing temperature exposure time.

EFFECT: providing additional reliable sealing of coupling and conical threaded connection at brazing.

1 cl, 4 dwg

Description

The invention relates to a device for sealing pipe couplings used in the oil and gas industry.

A device for soldering products [1] is known, including a lodgement for placing the soldered product on it, balls for pressing the soldered part during the soldering process, a grid forming a volume for placing the soldered product, vertical partitions located above the grid and dividing the volume into sections for placement in them balls. The disadvantage of this device is that it is quite complex, the brazed part is heated together with the device in the furnace, which makes the soldering process long and, therefore, inefficient.

A device for flux-free brazing of pipelines [2], consisting of a crimping device with a heater. The heater is made of a multilayer material with high resistivity and in a compressed form is a cylinder with multilayer walls sandwiched between conductive plates that are split in height and pairwise rigidly connected by a heat-insulating aggregate.

The disadvantage of this device is the unevenness of heating with a stepwise arrangement of soldered parts, as well as the inertia of the heating process.

Closest to the present invention is a device for induction brazing of a waveguide coupling [3], comprising an inductor covering the waveguide tube, made in the form of a cooled current conductor bent along the contour of the waveguide tube and placed in the groove of the coaxial magnetic circuit, and a ferrous metal substrate with a passage window for waveguide pipe and coupler.

The disadvantage of this device is the difficulty of holding the heating temperature in the range above the melting temperature of the solder and below the melting temperature of the connected parts, which often leads to a melt of the pipe wall of the waveguide.

The objective of the invention is to eliminate the disadvantages indicated in the above devices, including in the prototype.

An object of the invention is to develop a device that provides additional reliable tightness of the sleeve and conical threaded connections during soldering.

It is known [4] that leakage of threaded connections of columns is the cause of gas leakage (gas manifestations) in 80% of cases, which leads to large gas losses and is unsafe. Therefore, it is desirable to provide additional tightness of the coupling and conical threaded connections without changing the existing ones.

The technical result is achieved by a device for additional sealing of sleeve and conical pipe threaded joints, which includes a ring-type inductor, a thermocouple, an amplifier of thermoelectromotive force (voltage) arising in the thermocouple, a relay whose current flows through the thermoelectric power of the thermocouple, and an energy source for inductor and timer. All these elements are connected to each other as follows: the inductor covers the coupling (conical threaded connection) on the outer surface or in the end part, or in the middle of the length of the coupling. An electric power is supplied to the inductor, for example, from a mechanical current transducer with a frequency of 2.5 kHz, and one power line passes through a relay contact, the winding of which is supplied with electric current from the thermocouple of the thermocouple, which increases its value with an amplifier. The relay has the ability to interrupt the power supply of the inductor. The second line of electric power to the inductor passes through a timer, which breaks this line after a certain time.

What is new is that the device includes an annular inductor for melting the solder, mounted on the ends of the coupling (connected pipes) or in the middle thereof.

The device incorporates thermocouples that produce thermoelectric power, and with which the temperature in the soldering zone is measured.

The automatic system, which is an integral part of the device, maintains the set temperature in the soldered joint zone and is resistant! from: a thermocouple, an amplifier with thermoelectric power from it, a relay breaking the power supply circuit of the inductor when the set temperature is reached, a timer providing a certain time to maintain the set temperature.

Salient features of the device are:

- the presence of an annular inductor for melting the solder, installed at the ends of the coupling (connected pipes) or in its middle;

- the presence of a thermocouple for generating thermoelectric power in order to measure the temperature in the soldered joint zone;

- the presence of an automatic system for maintaining the set temperature in the solder joint area, consisting of: a thermocouple, an amplifier with thermoelectric power from it, a relay breaking the inductor power supply circuit when the set temperature is reached, a timer providing a certain time for maintaining the set temperature.

The use of new features ensures the achievement of the technical result of the invention, namely: additional sealing of the pipe joints during column formation.

We have not identified sources containing information on technical solutions, including the entire set of features of the invention, which allows us to conclude that it meets the condition of novelty.

We have not found sources of patent documentation and scientific and technical literature describing information about the influence of the distinctive features of the device on the achieved technical result. The technical solution does not explicitly follow from the prior art, i.e. inventive step meets the condition.

The invention is illustrated by drawings. Figure 1 shows the coupling and conical threaded connections having additional soldered seams.

Figure 2 shows the inductor when forming the lower end brazed seam. Figure 3 shows the position of two inductors forming the upper end brazed seam and a brazed seam between the ends of the pipes to be joined. Figure 4 schematically shows a device for forming a soldered seam between the ends of the connected pipes. Figure 1, in the form "a" shows a longitudinal section of the coupling connection, which includes the connected pipe 1 and 8 using the coupling 4. At the ends of the pipes made thread 2, which provides screwing of the pipe into the thread of the coupling 5. At the coupling, at the ends with on the inside, chamfers 9 are removed that provide a recess between the sleeve 4 and pipes 1 and 8. In these recesses, solder seams 3 and 7 are placed. In the gap, between the ends of the pipes to be connected, there is a solder seam 6. A conical threaded connection is shown in view “b” consisting of a girth pipe 13 and a girth a common pipe 10. A bevel is removed at the end of the bending pipe 10, which provides a recess for the location of the soldered seam 12. A soldered seam 11 is placed between the end of the bent pipe 13 and the inner surface of the bending pipe 10. Figure 2 shows the position of the inductor 15 when forming the lower the end seam 7 on the coupling 4 and the pipe 8. In this case, the chamfer at the end of the coupling 4 is not removed. Figure 3 shows the position of the inductors 14 and 15 during the formation of the upper end sleeve joint weld 3 and the solder joint 6 between the ends of the connected pipes 1 and 8. The chamfer on the sleeve 4 was also not removed. Figure 4 schematically shows a device for the formation of a soldered seam (for example, taken the seam between the ends of the pipes to be connected by a sleeve). The inductor 14 is located in the middle of the length of the coupling, clasping it on the outer surface with a certain gap. On the surface of the coupling, outside, at some point, a thermocouple 16 is fixed, the wires from which are connected to the thermoelectric power (voltage) amplifier 17. The electric current provided by the thermoelectric power (thermoelectromotive force) of the thermocouple 16 flows through the coil of the relay 18, the contacts of which provide for switching the power supply on and off on one line of the inductor 14 from the source 19. The timer 20 maintains the temperature in the solder joint area for the required time by breaking the second line power supply of the inductor 14 from the source 19.

The formation of additional sealing joints is carried out in the following sequence.

Initially form the lower solder joint 7 in the sleeve connection. Before the beginning of its formation, the issue of chamfering at the ends of the coupling on the inside is being decided. If you decide to chamfer, then this is done. The presence or absence of a chamfer does not change the technological process. But with a chamfer, the soldered seam is thicker in cross section, which provides greater strength and better additional tightness of the joint at the ends of the coupling. So that the molten solder does not flow down from the soldering zone, under the influence of gravity, the lower pipe 8 is turned over with the coupling 4 screwed on previously to its end 4. When screwing the coupling onto the pipe, all currently used methods for sealing a threaded joint, for example, the use of sealing lubricant, are performed . After turning the pipe with the sleeve, the brazed surfaces are fluxed so that the oxide film is removed and the solder is well bonded to the pipe and sleeve material. As flux, for example, zinc chloride can be used [6]. After that, along the perimeter of the outer surface of the pipe 8, the solder in the form of a round bar is laid in the place where it touches the end of the coupling. Since the solder is sufficiently plastic, it adheres well to the pipe 8 and sleeve 4. Then, an inductor 15 is installed, see Fig. 2, the middle of which is opposite the solder bar, and is included in the operation. When the soldering temperature is reached (slightly higher than the temperature of the complete melting of the solder), for example, for POS 40 solder, this temperature is about 250 degrees Celsius [7], further heating is stopped, the soldering zone is kept at this temperature for a certain time (several minutes), the heat source is turned off (inductor 15) and allow the soldering place to cool in air. The result is a sealed solder joint 7, which further seals the sleeve connection on the underside of the sleeve. After that, the pipe 8 with the sleeve and the brazed seam 7 is turned back to the position that it will occupy in the column, i.e. the pipe is below, and the coupling is above. After this, the end face of the pipe 8 is processed with flux, see Fig. 3, and a rod solder in the form of a ring is laid on it. Then, the end face of the pipe 1 is processed by flux, which is screwed into the sleeve 4 using, at the same time, the currently used sealing methods, in particular lubricants. After that, the soldering zone is processed by the flux at the place of contact of the upper end of the coupling and the outer surface of the pipe 1 and the solder is laid on the ring. Then, inductors 14 and 15 are installed opposite the solder rings as a heating element (although another type can be used), they are included in the work similarly to the previously described. The result is sealed solder joints 3 and 6, which additionally seal the coupling joint. When using the proposed method of additional sealing of a conical threaded connection, the soldered seams 12 and 11, see figure 1, view “b”, form: a soldered seam 12 - at the point of contact of the end of the clasped pipe 10 and the outer surface of the clasped pipe 13. In this case, it can be removed a chamfer from the inner edge of the end of the grasping pipe 10 (the chamfer shown is shown in the drawing) or not. The position of the joint when soldering is such that the end of the bending pipe is directed upwards. A brazed seam 11 is formed between the end of the wrapped pipe 13 and the opposite surface of the pipe 12. Figure 1 shows soldered seams that additionally seal the sleeve and conical threaded pipe joints in the column. The device itself works as follows. Figure 4 shows, by way of example, its position when a solder seam is formed in the gap between the ends of the pipes to be joined. The heating element in it is an inductor 14 with a power supply 19. The inductor is mounted on the outer surface of the coupling 4 opposite the future soldered seam (opposite the gap between the ends of the connected pipes). Solder is pre-laid in this gap. Between the inductor and the outer surface of the coupling 4 there is a small space (several millimeters). A thermocouple 16 is placed on the outer lateral surface of the coupling, tightly to it, the outputs of which are connected to the amplifier 17, and it, in turn, has an electrical connection with the coil of the relay 18, through which an electric current flows, which is formed by the thermopower of the thermocouple. In the initial state, the relay contact is closed, and the electric power line of the inductor 14 from the source 19, passing through the relay 18, is closed. The second power line of the inductor 14 from the source 19 will also be closed when the timer starts counting down the time set on it. The operation of the inductor is switched on by a timer. The temperature of the outer surface of the coupling 4 rises. A thermocouple generates a thermoelectric power, from which an electric current begins to flow through the electric circuit: the higher the junction temperature of the thermocouple, the greater the thermoelectric power, the stronger the current in the circuit. The device is configured in such a way (relay 18) that when a certain surface temperature is reached where the thermocouple is located, the current strength in the relay winding will reach a value sufficient to break the contact of the inductor power circuit. The latter turns off and the heating stops. The temperature at the thermocouple location drops. The current strength in the circuit decreases, the relay closes the power contact of the inductor, which again turns on and carries out heating. So the inductor will turn on and off cyclically, ensuring that the temperature in the thermocouple zone is maintained at a given level. Due to thermal conductivity, heat from the lateral outer surface of the coupling will be transmitted through the wall of the coupling to the solder location zone. The temperature on the outer surface of the coupling is selected so that heat is transferred to the soldering zone, sufficient to melt the solder. And this temperature depends on the wall thickness of the coupling and the wall thickness of the connected pipes, the thermal conductivity of the material of the coupling and pipes, etc. And it is selected in each case. The cyclic inclusion of the inductor will continue for as long as determined by the time the soldering temperature is held, and is set by a timer. This time is also determined for each specific case. At the end of the solder holding time, timer 20 breaks the inductor's electrical power circuit, which turns off, and heating stops. Further, the place of heating is cooled in air. As a result, a solder joint is formed, providing additional sealing of the coupling joint.

The proposed method for additional sealing of sleeve and conical threaded joints will reduce gas occurrences in the wells, thereby increasing the safety of their operation, and reducing gas losses.

Information sources

1. RF patent No. 1396396. The device for soldering.

2. RF patent No. 1329928. Device for flux-free soldering of pipelines.

3. RF patent No. 2297308. Device for induction soldering of a waveguide coupling.

4. Karabanov V.V., Bokhorov I.O. The solution to the problem of tightness and reliability of casing strings (in order of discussion). Article in J.: “Oil Economy”, No. 1, 2012 - P.42-45.

5. Handbook soldering / Ed. Lotsmanova S.N., Petrunina I.E., Frolova V.P. - M.: Mechanical Engineering, 1975. - S. - 88, 90, 111.

Claims (1)

A device for additional sealing of sleeve and conical pipe threaded connections, characterized in that it includes a heating element, for example a ring-type inductor, a thermocouple, an thermoelectromotive force amplifier arising in the thermocouple, a relay through which a current flows due to the thermoelectric power of the thermocouple, an energy source for the inductor and the timer, and the relay breaks the electric power line of the inductor when the temperature of the complete melting of the solder in the soldering zone is reached, and the timer breaks the second line on the expiry of the time delay soldering temperature.

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