DE3508590A1 - Cylindrical foam go-devils for cleaning pipes and process for the production thereof - Google Patents

Abstract

A cylindrical foam go-devil for cleaning pipes is claimed which consists essentially of a core made of soft-flexible foam and a covering of homogeneous elastomeric plastic in which longitudinal reinforcements of an elastomeric material are disposed in the core and/or in which the head and base sides are designed reinforced such that they act as pneumatic and/or hydraulic sealing discs. Processes for producing such go-devils are also described.

Description

Cylindrical foam pigs for cleaning pipes

and methods of making them Description The The present invention relates to cylindrical foam pigs, which essentially made of a core made of flexible foam and a sheath made of elastomeric material Are made of plastic, with roughening materials in the sheathing, if necessary Roughening tapes or scrapers are anchored.

Pipelines tend to form deposits on the wall. These deposits must be removed from time to time. One way that To carry out cleaning consists in piston-like by means of a propellant medium Devices through. to press the pipelines. Such Rei n; r devices are in german Usage of pigs ge Depending on the application, there are different versions for newts. However, what all designs have in common is that they are in their outer part are made of an elastic plastic (sealing surface to the pipe wall).

Pigs are known which are constructed from sealing disks, with a different number of sealing washers are mounted on a steel body. There are also known pigs made entirely of elastic foam are. Such pigs usually have the shape of a cylinder, with the height of the cylinder is usually about 1.3 times the diameter. Open-cell newts Foam is mainly used to dry damp pipes. Because elastic In terms of their physical properties, foams are inferior to homogeneous elastomers are (low tear strength, tear resistance, elongation at break, etc.), such Naturally, pigs do not loosen any incrustations from the pipe wall. There were therefore Developed newts, their foam core in whole or in part with are covered with an elastic coating made of homogeneous elastomer. In this coating In addition, abrasive substances such as metal carbides, metal oxides, e.g. corundum, or brush belts made of hardened steel bristles, so-called roughening belts, integrated be. A characteristic of such pigs, however, is that the coating is relatively less Thickness up to a maximum of 5 mm is applied. It turned out, however, that with such Pigging is often the weak point in the design of the load-bearing capacity of the foam base lies. Such pigs are often in the lines during the cleaning process torn. A relatively thin coating is not able to adequately protect the pig to stabilize, i.e. to hold the foam core together. The damage showed that the pigs were mostly torn across the direction of travel, which suggests lets the greatest forces act in the longitudinal direction. This occurs specifically occurs when the pipe to be cleaned has cross-sectional constrictions, e.g. due to weld seams, having. The removal of destroyed pigs from pipelines can under certain circumstances can be very time consuming and expensive.

The object of the present invention is therefore to provide a safe to use To provide a pig that is specially stabilized in the longitudinal direction. Since disc pigs are also known to have a good cleaning effect have, however, not enough flexibility due to the assembly on a steel body have to pass tight pipe bends, it is also an object of the present Invention, the advantages of disc pigs with the flexibility of a foam pig body to combine, with the possibility of integrating roughening bands, abrasive Fabrics or homogeneous polyurethane-elastomer strips in the longitudinal surface should be preserved. Another object of the present invention is to provide methods to create such pigs.

This object is achieved according to the invention in that in Core made of flexible foam. Longitudinal reinforcements made of an elastomeric material and / or the head side and the foot side with a head cap and a foot cap is designed reinforced so that it can be used as pneumatic and / or hydraulic sealing washers works. A particularly suitable method for producing such pigs is thereby characterized in that one first has a flexible foam core provided with channels produces and pours the channels with the elastomeric material, where appropriate at the same time the reinforced head cap and the reinforced foot cap, which are pneumatic and / or hydraulic sealing washers act, are cast. Preferably brings before pouring the channels with the elastomeric plastic, a flexible reinforcement into the channels, in particular so that they may be after pouring protrude into the reinforced head cap and foot cap and thus additional head cap and hold the foot cap together.

The foam pig manufactured according to the invention with longitudinal stabilization is characterized by the fact that a complete tearing apart - as it is with only pigs provided with a surface coating is known - no longer occurs. Small pieces can only be removed from the pipe with the most unfavorable pipe conditions Tear out the foam. Also the likelihood of the pig jamming occurs in the pipelines, is much less because of the longitudinal reinforcements excellent stabilization in the longitudinal direction is achieved, so that a Compression in the longitudinal direction and thus less wedging in the pipe is expected. Due to the fact that the roughening tape is poured into the homogeneous polyurethane elastomer the head cap and the foot cap becomes a very durable connection of the buffing tape reached with the pig body.

The invention is explained below with reference to FIGS. 1 and 2, which show a according to the invention represent particularly preferred embodiment, explained without them however, to be restricted to this. All not mentioned in the description, but out Details that can be seen in the drawings are part of the disclosure of the present invention Invention.

In Figs. 1 and 2, and in the associated parts of the description the reference symbols have the following meaning: 1 flexible foam core 2 Coating made of homogeneous elastomeric plastic 3 Longitudinal reinforcement made of homogeneous elastomeric plastic, preferably made of polyurethane elastomer 4 or roughening tape homogeneous elastomer, preferably polyurethane elastomer 5 head cap made of elastomer Plastic 6 foot cap made of elastomeric plastic Fig. 1 shows on the left, with A designated side, a longitudinal section through the foam pig according to the invention, and on the right side labeled B, a plan view of the invention Foam pig.

Fig. 2 shows the invention in a perspective view Foam pig.

The foam pigs according to the invention are produced in such a way that that initially a foam raw body is produced in the desired pig shape will. The blank can either be worked mechanically from a block or by foam molding. As materials suitable all flexible foam plastics with a density between 25 and 450 kg / m3. The foam body is preferably made from a soft elastic one by foam molding Polyurethane foam produced with a density of approx. 120 kg / m3. This raw body is provided with one or more channels - as indicated in FIG. 2. Here is the size of the additional number of channels added to the central channel of the pig and the application. Newts, the heavy loads (evoked due to large changes in cross-section or tight pipe bends) a greater number of channels. The channels can be formed by suitable shaping the foam molding can be generated or worked out afterwards. It it is also possible to insert lost plastic pipes during the foaming process, which then remain in the pig body.

The raw foam body produced in this way is then on its longitudinal side Surface in a manner known per se, either by spray application or by pouring, Filling or painting with an elastomer application in a thickness between 1 and 3 mm coated. The elastomer is preferably a thermosetting polyurethane system with a Shore hardness range between 60 and 90 Shore.

During this process, roughening tapes are made from textile fabric with hardened steel bristles or strips of homogeneous polyurethane elastomer in a thickness of 5 to 20 mm integrated into the surface. This is done in the Way that the roughening bands in the still liquid or flowable coating or polyurethane strips are pressed and fixed until hardened. In the However, coatings that are still liquid or flowable can also be those already mentioned abrasive substances, e.g. powdered metal carbides or metal oxides will. The roughening tapes or polyurethane eastomer strips are spiraled up arranged on the surface, as can be seen from FIG. Preferably be the roughening tapes for better fixation or polyurethane elastomer strips in corresponding recesses of the foam raw body, in which the still liquid elastomer is located. The additionally attached roughening tapes, Polyurethane strips or abrasive additives are used to special, depending on the application cleaning tasks to be performed.

After this operation, the head cap and the one with the propellant in contact with the pig's foot cap. These two parts are called Sealing washer designed, the foot cap being first made in a mold. The still liquid polyurethane elastomer is poured through the central bore. It spreads out at the bottom of the mold and rises to a predetermined height on the Edge up. Here, the roughening tapes or polyurethane elastomer strips are in the foot cap is also poured in, which prevents it from being torn out of the surface largely protected. After manufacturing the foot cap in a thickness of 1 to The central duct and any additional ducts are now 50 mm Casting channels, preferably with additional reinforcements in the form of natural, Plastic or wire ropes are introduced. The polyurethane-elastomer longitudinal reinforcement there is an intimate connection with the foot cap and the foam core of the pig a.

The head cap of the pig is then also in a shape and also applied to the foam core in a thickness between 1 and 50 mm, also an intimate connection with the "inner elastomer reinforcing rods" comes about. The roughening tapes that may be present are also used here or polyurethane elastomer strips cast into the head cap and so against Protected from tearing away. The polyurethane elastomer is preferably an elastomer in a Shore hardness range between 60 and 80 Shore.

Claims (5)

Claims 1. Cylindrical foam pig for cleaning of tubes, consisting essentially of a core (1) made of flexible foam and a sheath (2) made of a homogeneous elastomeric plastic, with optionally abrasive substances or roughening strips (4) or wipers anchored in the casing are, characterized in that the core (1) is made of flexible foam Longitudinal reinforcements (3) made of an elastomeric material are located and / or the head side and the foot side is reinforced with a head cap (5) and a foot cap (6) are that they act as pneumatic and / or hydraulic sealing washers. 2. Pig according to claim 1, characterized in that the longitudinal reinforcements (3) additionally have a reinforcement made of the elastomeric material. 3. Pig according to claim 2, characterized in that the reinforcement is a flexible rope, preferably one made of hemp. 4. A method for producing foam pigs according to claim 1 to 3, characterized in that a soft elastic one provided with channels is first used Manufactures foam core (1) and pours out the channels with the elastomeric material, where optionally the reinforced head cap (5) and the reinforced one at the same time Foot cap (6), which act as pneumatic and / or hydraulic sealing washers, to be poured. 5. The method according to claim 4, characterized in that one is before the pouring of the channels with the elastomeric plastic reinforcement, preferably one in the form of a flexible rope into which channels are introduced, preferably so that the reinforcement protrudes into the head cap and the foot cap to access them Way to hold the head cap together with the foot cap.