DEVICE FOR MEASURING THE DISTANCE BETWEEN TWO UNDERWATER ELEMENTS OF TRAWL GEAR ESPECIALLY THE VERTICAL DISTANCE

摘要

1337079 Pressure gauges MORSKI INSTYTUT RYBACKI 19 April 1971 [18 Feb 1970] 23139/71 Heading G1L In a device for measuring the vertical distance between two underwater elements of a trawl gear, such as the mouth of a net 31, an elastic vessel 4, connected to an elastic membrane 12 by a conduit 5, is attached to the bottom line 34 of the net 31 and an instrument 32 is attached to the headline 33 and the arrangement is such that pressure on the vessel 4, filled with a gas such as air, is transmitted to the membrane 12 which in turn transmits such pressure to a second incompressible liquid such as silicon oil, in an anti-chamber 11 and if the pressure is lower than the pressure internally of an encased bellows 1 caused by the surrounding environment, the bellows 1 alters in length and, through a follower 18, moves a pen system 3 over a driven tape system 21-23. If the pressure exerted by the liquid 11 on an encased bellows 15 exceeds that of the surrounding environment the bellows 15 alters in length to move a ported piston to actuate a cutoff valve 2, to shut off the pressure supplied to the external of the bellows 1 through a conduit 10. The driven tape system 21-23 is automatically switched on at approximately a depth of 5 metres by an hydrostatic switch.