GB810995A - Device for gauging fibre characteristics - Google Patents

Abstract

810,995. Testing physical properties. SHEFFIELD CORPORATION. Jan. 3, 1957 [Jan. 5, 1956], No. 286/57. Class 106 (2). An apparatus of the air flow type for gauging fibre characteristics, as determined by the resistance to air flow of a fibrous mass, has manually controlled means 74, 75 adapted automatically and sequentially to insert a fibre compressing plunger 12 into a fibre receiving chamber 11 and supply a gauging flow of air through a flow-responsive indicating instrument 17 and to the chamber 11. The manually controlled means 74, 75 are also adapted automatically and sequentially to retract the plunger 12 from the chamber 11 and cut off the flow of air. The indicating instrument 17 is an internally tapered tube in which the rate of flow is indicated by a float 16, and which has adjustments 22, 24 to alter the zero position and amplification ratio respectively. Fig. 2 shows the details of the chamber 11 and the plunger 12. The lower end of the chamber 11 is formed by a perforated plate 30, below which is a connection 21 to the indicating instrument 17. The lower end of the plunger 12 also supports a perforated plate 32 and a fibrous mass to be tested is compressed to a predetermined extent between these plates 30, 32. The plunger 12 is supported by a rod 40 leading from a piston in an air-actuating cylinder 41 and has slight horizontal movement relative to the rod 40 on a pin 44, limited by a flange 46, and the upper edge 47 of the chamber wall is rounded, thus eliminating the possibility of jamming. The operation of the apparatus to test the resistance to air flow of a known mass of fibre is as follows. A mass of fibre to be tested is placed in the chamher 11, plates 70, 77 on valve units 74, 75 are simultaneously depressed and this supplies compressed air from inlet 69 by connections 80, 84 to the upper end of cylinder 41 so moving the plunger 12 into the chamber 11. Air also flows through an adjustable constriction 110 and conduit 97 to a valve 91, which acts, when sufficient pressure has been built up, to pass air from inlet 69 and conduit 90 to the inlet 20 of the indicating instrument, thus giving a reading of the air flow through the fibrous mass in the chamber 11. When a reading has been taken, plates 76, 77 are released and air flows from inlet 69 to conduit 85 and the lower end of cylinder 41, thus withdrawing the plunger 12, and at the same time conduits 97 and 84 are connected to exhaust 87. Thus the pressure in conduit 97 falls, and valve 91 cuts off the air supply to the indicating instrument 17. However, the constriction 110 acts to delay the operation of valve 91 and so the air continues to flow for a short time into chamber 11 and ejects the fibrous mass. To set up the apparatus, a master 60, shown in Fig. 5, is used. The master 60 is connected permanently by a flexible conduit 61 with a manometer mounted on the indicating instrument 17, and has passages 66 including restrictions 67, 68. A maximum flow condition is obtained and determined by restriction 68 when the outlets are unrestricted, and a minimum flow condition determined by restriction 67 when a finger is placed over outlet 70. Thus one master 60 can be used for adjusting the amplification and zero position of the instrument 17. Reference has been directed by the Comptroller to Specification 771,107.