MXPA01005611A - Service riser - Google Patents

Abstract

A service riser (10) comprises a steel jacket (11) around a polyethylene pipe (12) which terminates in the riser at a transition zone (20). The transition zone (20) comprises a retainer sleeve (30) inserted in the end of the pipe (12) and sealed thereto by an O-ring (38). The retainer sleeve (30) extends out of the pipe (12) and is provided with grooves (46) separated by lands (48) on which an elastomeric sealing band (52) is received. The tube (11) is swaged down forming a swage groove (56) around the retainer sleeve (30) compressing the gasket (52) to a large extent over the lands (48) and a lesser extent over the grooves (46), the ideal compression for the gasket (52) being arranged somewhere between such degrees of compression. By this means the ideal degree of compression at some regions of the gasket (52), forming an annulus around the retainer sleeve (30), is guaranteed, despite tolerances in the dimensions of the tube (11) (especially) as well as the band (52) and sleeve (30).

Description

SERVICE ELEVATOR DESCRIPTIVE MEMORY This invention relates to a service elevator, particularly for use in the gas supply industry. Gas is increasingly supplied through plastic conduits, especially polyethylene conduits, though not exclusively. The main advantage of plastic conduits is their resistance to corrosion and their flexibility. However, when a plastic conduit is buried under the ground and rises to the surface to supply a house or other establishment, it is convenient to shield it. Of course, it also requires an adapter at its end for connection to a meter or other equipment in the house. In fact there are several regulations in different jurisdictions that request this additional protection in the transition from subsoil to soil. Numerous patents describe these systems. For example, U.S. Patent No. A-4482170 (Jacobson et al) discloses a gas lifting apparatus in which the diameter is reduced to a section of a metal tube to produce an internal step. The plastic conduit ends with an internal reinforcing handle (to give the duct radial compression force), forging a collar around the end of the duct, with teeth in the collar fitting into the plastic material. The end of the duct is inserted back into the metal tube with the collar pressed between itself and the internal step, an elastomeric seal ring that seals the tube against the conduit in this way. Then the tube becomes the gas carrier and the common connection means are provided at the end of the tube to connect to a meter etc. The tube is finally fixed or nailed to the collar to retain the collar in position. The tube is usually mild steel, satisfying the specific requirements but, generally, it has a fairly wide tolerance in its dimensions. Thus, for example, a thread typically formed at its end is gradually lowered frequently, at least partially in order to accommodate these wide tolerances. The patent of E.U.A-A-4801159 (to Sehorn) describes another suitable device, not different from the device described above. Other devices are described in the patent of E.U.A-A-4519634, E.U.A-A-5590914 and EP-A0539728. US-A3987820 (to Alewitz) discloses a transition joint in which a multi-part transition handle terminates the end of a plastic gas main and has molded plastic collars at its exposed ends retaining therebetween elastomeric seals, one by reducing the diameter of a section of a protective tube that is around, embedding itself in the plastic collar to hold the transition joint in place and another sealing by means of reduction of the diameter of the transition handle to the tube through elastomeric seals. Since the metal tube is at least partially taken underground, it is necessary that it be provided with an effective environmental protection. This is usually achieved by coating with an epoxy resin or the like or by galvanizing the tube. In this case, a minimum of treatment will be performed when connecting the tube to the end of the gas conduit to avoid disturbing the environmental protection. However, some methods include fitting an adapter to the end of the conduit and then welding the adapter to the tube. Of course, this makes the reapplication of the protection necessary. It is therefore an object of the present invention to provide an elevator that is simple to construct, satisfies all relevant standards and requirements and has a minimal fracture of the environmental seal. According to the present invention, there is therefore provided an elevator comprising: A plastic conduit sealed within a protective tube at the midpoint between its ends; A retaining handle and compression band at the end of the conduit compressing the conduit wall therebetween and retaining and sealing the handle in the conduit characterized in that the retaining handle is integral integral and extends from the end of the conduit; Y, An elastomeric band in the retention handle beyond the end of the conduit and compressed against the handle by a reduction in the diameter of a section of the tube; Characterized in that the handle has at least one circumferential step covered by the elastomeric band so that the elastomeric band is compressed to different degrees on each side of the step, and characterized in that the material of the elastomeric band has an ideal degree of compression for conditions of optimum sealing between two objects, and characterized in that the elastomeric band is compressed to a lower first degree on one side of the step and a higher second degree on the other side of the step, resting the ideal degree of compression between the first and second degrees for all size tolerances of the handle, elastomeric band and tube. Preferably two steps are provided defining a slit. In fact, there may be several slits axially spaced along the handle. In addition, the slits can be of different depths. Preferably, the handle widens at least on one side of the reduced diameter section to resist removal of the conduit in the direction of the reduced diameter section. However, preferably, the handle widens at its end furthest from the conduit. Preferably the handle in contact with the conduit has a grooved profile so that when gripping between the handle and the band of compression, the conduit material flows cold inside the grooves of the handle. Preferably, at least one slit is formed between the ridges to receive an elastomeric circular ring seal to seal the handle with respect to the conduit. In another aspect, the invention provides a service elevator for a gas line comprising a conduit of plastic material, characterized in that the service elevator comprises a metal tube that surrounds and protects the conduit and that transfers the gas flow from the conduit to the tube, the tube having two ends, one end having a connector for gas equipment and the other end surrounding the conduit, the end of the conduit terminating at the midpoint between the ends of the tube in a transition junction, the transition junction a transition handle partially inserted at the end of the conduit and having a compression band around the end of the conduit so that the end of the conduit is pressed between the transition handle and the compression band to retain and seal the conduit. handle in the duct, the exposed end of the transition handle having a widened end, and circumferential grooves spaced apart An enlarged elastomeric band is disposed at the exposed end, the diameter of a section of the tube being reduced around the exposed end to prevent removal of the conduit from the tube, at least in the direction of its end surrounding the conduit, and for compressing the elastomeric band to seal the retaining handle to the tube. The invention is further described herein, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of an elevator in accordance with the present invention; and Figure 2 is a section along the line ll-ll in Figure 1, showing a detail of the transition zone. A gas service elevator 10 comprises a lightly bending metallic tube 11 which receives a plastic conduit 12. The end of the conduit 12 ends inside the tube 11 near its end 14 where the tube 11 is externally screwed to receive the coupling of a gas meter, manifold or other equipment (not shown). Where duct 12 exits at the other end 16 of tube 10, a moisture seal is provided to prevent ingress of moisture between duct 12 and tube 11. In practice, duct 13 is underground and connected to a gas master pipe. In fact, the tube 12 may be provided with a land line mark 18 showing the intended ground level. Although the elevator 10 is shown with a curve at an angle of approximately 90 degrees, (with a radius R of about 30 cm), other forms of elevator are known, such as straight elevators and protected elevators, not by the solid tube 10 as shown in FIG. shows, if not flexible nozzles, so that it can be turned at any desired angle. Without However, none of these alternate forms are relevant to the present invention which deals with the transition zone 20, which is shown in more detail in Figure 2. Referring to Figure 2, the plastic conduit 12 within the tube 11 it may be further protected by a mesh 22. Prior to assembly, a retaining handle 30 is inserted into the end 32 of the conduit 12. The retaining handle 30 has numerous grooves 34 including a slit 36 about half its length and incorporating an elastomeric circular ring seal 38. After the insertion of the retaining handle 30 at the end of the conduit 32, a compression band 40 slides over the end of the conduit 32 and is compressed radially in order to cause the material duct plastic 12 cold flow through grooves 34 making removal of retaining handle 30 from duct 12 substantially impossible. In addition, the compression places the material of the conduit 12 in intimate compression contact with the elastomeric sealing ring 38 in order to carry out a complete gas seal between the retaining handle 30 and the conduit 12. An exposed end 42 of the handle retainer 30 extends from conduit 12 and has a substantially cylindrical surface 44 having a plurality of circumferential grooves 46. Slits 46 define steps 48 surrounding each indentation. At this distal end, the handle 30 is provided with a flared or flared shoulder 50.

Prior to insertion into the tube 11, an elastomeric band 52 is placed over the exposed end 42 of the transition handle 30 overlaying several slits 46 and steps 48. The lifter is now ready for assembly and the conduit 12 with the retainer 30 protruding it is inserted into the tube 11 until the retainer is positioned approximately 7 cm from the threaded end 14 of the tube 11. When placed as required, a tube diameter reduction tool compresses the walls of the tube 11 to form a slit 56 by reducing the diameter of a section of the tube around the entire periphery of the tube 10. Internally, the slit 56 by reduction in diameter, compresses the elastomeric band 52 in the slits 46. The enlarged end 50 rests on an upper shoulder 58 of the slit by reduction of diameter 56 and prevents the duct 12 from coming out in the direction of the end 16 of the tube 10. The outlet of the duct in another direction is not generally a problem, however, an enlarged edge may be provided at the other end of the slit by reduction in diameter 56 in the retaining handle 30. However, equally important, the elastomeric sealing band 52 also performs a sealing between the transition handle 30 and the tube 11 so that there is now a gas passage sealed from the interior of the conduit 12, through an inner diameter 60 of the transition handle 30 and to the tube 11 adjacent its threaded end 14.

The tube 11 can thus be provided pretreated with an epoxy coating or a galvanized surface, it being found that the diameter reduction operation does not interfere with the effective protection afforded by the environmental coating thus formed. The typical standard for gas pipes (constituted by the pipe 11 once the gas leaves the transition zone 20), uses a Schedule 40 steel pipe that has a wide tolerance in its dimensions. It is also known that the ideal degree of compression for an elastomer such as rubber BUNA-N is 25%, in order to achieve the most effective sealing and to ensure that the sealing is maintained in all environmental and service conditions that could experience It is for this reason that the slits 46 are provided so that, within all the tolerances of the handle 30, the band 52 and the tube 11, the elastomer covering the steps 48 will always be over-compressed (ie by more than 25%) . On the other hand, the elastomer covering the slits 46 will always be subcompressed (ie less than 25%). Accordingly, in the transition regions between the center of each slot 46 and the center of the adjacent steps 48, said ring-shaped regions being around the retainer 30, is where ideal compression is experienced. In this way, ideal sealing conditions will always be achieved for all component tolerances.

Claims (9)

NOVELTY OF THE INVENTION CLAIMS

1. - An elevator 20 comprising: a plastic conduit 12 sealed inside a protective tube 11 at the midpoint between its ends; a retainer handle 30 and compression band 40 at the end of the conduit between them compressing the conduit wall and retaining and sealing the retainer handle 30 in the conduit, characterized in that the retainer handle is integral integral and extends from the end of the conduit. conduit 12; and, an elastomeric band 52 on the retainer handle 30 beyond the end of the conduit and compressed against the handle by a reduction 56 of a pipe section of the pipe; characterized in that the holding handle 30 has at least one circumferential step 48 covered by the elastomeric band so that the elastomeric band is compressed to different degrees on each side of the step; and characterized in that the material of the elastomeric band has an ideal degree of compression for optimum sealing conditions between two objects, and characterized in that the elastomeric band is compressed to a lower first degree on one side of the step and to a higher second degree on the other side of the step, finding the ideal degree of compression between the first and second degrees for all the tolerances of size of the handle, elastomeric band and tube.

2. - An elevator according to claim 1, further characterized in that the two steps 48 are provided by defining a slot 46 therebetween.

3. An elevator according to claim 2, further characterized in that several of the slits 46 are provided axially spaced along the handle.

4. An elevator according to claim 3, further characterized in that the slits are of different depths.

5. An elevator according to claim 1, further characterized in that the handle is widened at least on one side of the diameter reduction 56 to resist removal of the duct in the direction of the section with reduced diameter.

6. An elevator according to claim 5, further characterized in that the widening 50 is at the end of the handle 30 that is farthest from the conduit 12.

7. An elevator according to claim 1, further characterized because the surface of the handle 30 resting on the duct 12 has grooves 34 therein into which the duct material flows cold during compression of the duct between the retainer handle 30 and the compression band 40. 8.- An elevator according to claim 1, further characterized in that a slit 36 is formed on the surface of the handle that rests on the duct and further characterized in that the Slit has an elastomeric sealing ring 38 that serves to seal the handle duct. 9. A service elevator 20 for a gas line 12 comprising a conduit of plastic material 12, further characterized in that the service elevator comprises a metal tube 11 that surrounds and protects the conduit and transfers the gas flow from the duct to the tube, the tube having two ends, one end having a connector 14 for the gas equipment and the other end surrounding the duct, the end of the duct terminating at the midpoint between the ends of the tube at a transition junction 20, the transition junction comprising a transition handle 30 partially inserted at the end of the conduit and having a compression band 40 around the end of the conduit so that the end of the conduit is pressed between the transition handle and compression belt. to retain and seal the handle in the conduit, the exposed end of the transition handle has a widened end 50, and circumferential grooves 46 remote from the tang end Nylon, an elastomeric band 52 which is disposed at the exposed end, reducing the diameter of a section 56 of the tube around the exposed end so as to prevent the passage of the conduit from the tube, at least in the direction of its surrounding end to the conduit, and to compress the elastomeric band so that it seals the retainer handle to the tube.