Abstract: A reliable sleeve unit with a water-absorbing swelling rubber that provides a reliable seal to a branch hole and the branch stop while controlling the development of rust. The rubber layer is applied on a cylindrical metal sleeve having a flange on its outer circumference in a manner such that a certain height length of the metal sleeve from its bottom end face is left uncovered. The height length of the flange is set to be long enough for the flange to be inserted into the inner circumference of the branch pipe to be connected to the branch hole. The rubber layer is applied onto the metal sleeve in a manner such that the height length of the rubber layer coating the metal sleeve is approximately equal to the wall height of the branch hole, or in a manner such that the bottom edge of the rubber layer is set to be higher than the bottom end face of the metal sleeve.

Abstract: The present invention teaches a concrete pipe joint construction which includes a steel bell and a spigot joint ring, both protected by an alkali releasing substance contained typically in a composite sleeve. When the spigot is engaged sealably into the bell an external joint recess is formed. The present advance is to add a sleeve made of a polyurethane foam material having the alkali releasing substance dispersed therein. The sleeve has an impermeable outer surface and goes around the outside of the joint and is banded sealably to both of the pipes. By this expedient, if and when ground water penetrates into the joint recess, the alkaline material is released from the sleeve to protect exposed steel from corrosion.

Abstract: A rust-resistant cylindrical metal sleeve for preventing rust and corrosion from developing around the wall of a branch hole when the sleeve is rigidly fitted into a branch hole that is drilled through the wall of a metal conduit such as a water pipeline. The sleeve has a projecting portion on its outer circumference and an inner flange portion inwardly projecting at its lower end. The metal sleeve on its outer circumference is coated with a water-absorbing swelling rubber into which a synthetic resin rubber and a water-absorbing polymer are blended. Preferably, 100 parts by weight of styrene-butadiene rubber or ethylene-propylene-dienemetylene linkage rubber is blended with 10 to 40 parts by weight of the water-absorbing polymer. Since the water-absorbing swelling rubber increases its volume as it absorbs water, pressure in the rubber increases, preventing water ingress through between the metal sleeve and the wall of the branch hole.

Abstract: The invention relates to a seal (1) for a joint comprising a cylindrical inner core layer (2) made of a water-unexpansible flexible material and having an internal opening (2a), and an outer coating layer (3) which is made of a water-expansible rubber. The outer coating layer (3) coats the inner core layer (2) and has penetrating openings (4) in the form of slits, pinholes or the like. The penetrating openings (4) extend to penetrating openings in the inner core layer (2) and communicate with the internal opening (2a) through the penetrating openings of the inner core layer (2).

Abstract: A washer system comprising: an annular washer having a central opening and an annular packing member which is coaxially arranged with the annular washer, at least a portion of the annular packing member being arranged within the central opening of the annular washer; at least a portion of the outer surface of the annular washer being rust-proofed treated. A substantial portion of a contacting surface between the annular washer and the annular packing member is not rust-proofed treated. The annular packing member is made of an elastic water-swellable rubber. The annular packing member has a portion which extends radially outwardly from a portion of the annular washer defining the central opening, and contacts a portion of a lower substantially flat surface of the annular washer radially outwardly of the annular opening. The annular packing member has a portion extending below a lower substantially flat surface of the annular washer.

Abstract: A seal, constituted by a water-expansible portion and a water-unexpansible portion, prevents water from leaking in a construction joint. The expansible portion surrounds the unexpansible portion everywhere except on a side of the unexpansible portion which is adhered to one of two mutually facing surfaces of the construction joint. The unexpansible portion is sized, relative to the overall size of the seal, particularly in the width dimension, so that it adheres with sufficient strength to one of the mutually facing surfaces of the construction joint so as not to become pulled off in use. An effective seal thus is maintained even in a swollen state.

Abstract: A pipe joint sealer for providing a watertight joint in metal pipe, cast concrete pipe, plastic pipe and the like is disclosed. The pipe joint sealer prevents fine dirt and sand from entering the pipe through the joint. The pipe joint sealer is comprised of an absorbent material such as low density, open cell, resilient foam which is saturated with a quantity of water reactive urethane prepolymer. The urethane prepolymer saturated foam is sandwiched between two layers of a geotextile fabric such as polypropylene which permit moisture to come into contact with the urethane prepolymer saturated foam. Moisture causes the urethane prepolymer saturated foam to expand and thereby form a dynamic watertight seal. Drying of the urethane prepolymer saturated foam causes it to shrink back toward its original volume. Thereafter, the pipe joint sealer of the present invention forms a new watertight seal each time it is wetted.

Abstract: A fluid-tight flexible connection comprises couplings (27, 28) of soft elastic material, inserted in cavities (11) of hollow sections (12, 13), flexible parts (29) of soft elastic material arranged between the couplings, nipples (32) of hard material inserted in passages (33) of the couplings (27, 28) and in transverse passages (34) of the flexible parts (29), the nipples having barbs (40, 41) exerting an expanding action, and having an internal bore (39). The nipples (32) provide a fluid-tight connection between the several parts, namely the hollow sections (12, 13), the coupling parts (27, 28) and the flexible parts (29), which connection has a comparatively high tensile strength in the direction of the cavities (11) by virtue of the barbs. The adjoining hollow sections (12, 13) can hinge relative to each other owing to the elasticity of the flexible part (29), the maximum hinge angle being determined by the elasticity of the flexible part (29) and its length.