# US 5,348,764 A · Method for impregnating a lining material with a hardenable resin

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- Number: US 5,348,764 A
- Document ID: US5348764A
- Status: Granted
- Kind: A
- Application number: 07/957,285
- Filed: 1992-10-06
- Granted: 1994-09-20
- Earliest claimed: 1992-10-06
- Assignees: Yasuhiro Yokoshima; Minoru Kamiyama
- Inventors: Yasuhiro Yokoshima
- Web page: https://patentgrep.com/patent/US5348764A

## CPC

- F16L 55/1651: {the flexible liner being everted}
- B29C 67/246: {Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM] (casting monomers B29C39/006, mixing construction B29B7/74)}
- B29C 70/44: using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding
- B29C 63/00: Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor (B29C73/00 takes precedence; by blowing B29C49/00; by thermoforming B29C51/00)
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

An improved method for impregnating a tubular lining material with a hardenable liquid resin employed in a pipe repair operation by lining the pipe internally with the lining material; the method comprises (a) supplying about the same amounts of the same hardenable liquid resin to two mixing baths, (b) mixing the hardenable liquid resin with an agent to retard hardening and another agent selected from catalyst to facilitate hardening and hardener in one of the mixing baths, and, at the same time, mixing the hardenable liquid resin with a hardening accelerator in another one of the mixing baths, (c) supplying predetermined amounts of these mixtures to a static mixer from the respective mixing baths, (d) mixing these mixtures together in the static mixer to obtain a final mixture of hardenable resin, (e) supplying the final mixture to the tubular lining material, and (f) impregnating the tubular lining material with the final mixture.

## Claims

### Claim 1

A method for pipe repair comprising the steps of
(a) supplying about the same amounts of the same hardenable resin to two mixing baths from a resin tank,
(b) mixing said hardenable liquid resin with an agent to retard hardening, at least one catalyst to facilitate hardening and hardener in one of said mixing baths to form a first mixture, and, at the same time, mixing said hardenable liquid resin with a hardening accelerator in another one of said mixing baths to form a second mixture,
(c) supplying amounts of said first mixture and said second mixture to a static mixer from the respective mixing baths,
(d) mixing said first mixture and said second mixture together in a static mixer simultaneously as the first and second mixtures are supplied to the static mixer, to obtain a final mixture of hardenable resin,
(e) supplying said final mixture to tubular lining material which has been placed within a pipe to be repaired, and
(f) impregnating the tubular lining material with the final mixture.

### Claim 2 (depends on 1)

The method as claimed in claim 1 wherein said hardenable liquid resin is a thermohardening resin.

### Claim 3 (depends on 1)

The method as claimed in claim 1 wherein said hardenable liquid resin is a photosensitive hardening resin and said hardening accelerator is a photosensitizer.

### Claim 4 (depends on 1)

The method as claimed in claim 1 wherein said step (c) consists of substeps of (i) supplying amounts of the resin mixtures from the respective mixing baths to separate two tanks installed in a transportable refrigerator, (ii) transporting the refrigerator to the repair site, and (iii) supplying the resin mixtures to the static mixer installed at the repair site.

### Claim 5 (depends on 1)

The method as claimed in claim 1 wherein said tubular lining material has its outer surface closely covered with a hermetic flexible film and in said step (f) the impregnation of the tubular lining material is facilitated by reducing pressure in said lining material with a vacuum pump.

### Claim 6 (depends on 1)

The method as claimed in claim 1 wherein a hermetic flexible film is loosely wrapped around said tubular lining material and in said step (f) the impregnation of the tubular lining material is facilitated by reducing pressure in the narrow space inside the yet flattened portion of the tubular lining material with a vacuum pump.