GB1445516A - Apparatus for testing the rain-resistance of fabrics - Google Patents

Abstract

1445516 Testing fabrics MARKS & SPENCER Ltd 9 May 1975 [11 Feb 1974] 06081/74 Heading D1S Apparatus for testing the rain resistance of fabrics by simulating natural rain characteristics comprises a generally tubular duct 3 arranged to be generally vertical in operation, a drop generator 4 adapted to provide a controlled shower of water drops within the duct 2, a randomising device 36, Fig. 4, at or near the bottom of the duct 2 and consisting of a mesh structure inclined to the vertical path of the drops within the duct 2, and a sample holder arranged below the bottom of the duct 2 and the device 36 so as to hold a sample 7 in the path of drops passing down the duct 2 and being broken into random-size drops by the device 36. The duct 3 may be an expandible, bellowstype tube, an interchangeable fixed length tube, a telescopic tube or, preferably, a series of flanged transparent polymethylmethacrylate tubes built up to the required length. The duct 3 and the device 35 in a base 5 are adjustably mounted on a column 2. A cut-off tray 6 and a support 9 for the sample holder are swivellably mounted on the column 2. A drip tray 10 is provided. A pump 12 feeds water from a reservoir tank 11 to the drop generator 4 and drainage lines 15, 16, 17 lead from the generator 4, the base 5 and the tray 6, respectively, to the tank 11. The generator 4 comprises a showerhead formed in a base 22 provided with barrels 24, e.g. foreshortened hypodermic syringe barrels, leading to needle jets 25 and arranged in two rings. An overflow line 28 provides a constant head. To clean the needles 25 in case of blockage, a connection 29 to a source of pressure pulsation, e.g. a squeeze bulb, is provided. The device 36, Fig. 4, comprises an interchangeable cone of mesh fabric e.g. a heavy quality nylon bolting cloth, and has a base diameter greater than that of the upper end of a cone 33 carried by a member 31 to provide a drainage zone 34. The sample is supported by an H-shape device comprising a cross member 41, Fig. 6, and limbs 42 having up- and inturned ends 43 supporting a sample holder 44 comprising a pad having on its underside a printed circuit pattern of conductive narrow strips separated by insulating zones. In operation, a sample 7 is placed over the pad 44 and held taut by weights 8 or clips. This sample is exposed to water droplets falling from the generator 4 through the cone 36 until the water penetrates the sample and gets onto the insulating strip between any two successive conductive strips of the pad 44 and causes a short circuit to operate a detecting circuit to stop the pump 12 and an associated timing clock and to initiate a warning, e.g. a lamp or buzzer, on a panel 13. In a modification, to simulate movement of the fabric during wearing, during testing, one end of the sample is reciprocated by an electric motor while the other end is held by weights.