Patent ID: 6360599
Filing Date: 2002-03-26
Classification: G01C,G01F

Abstract:
A device for measuring tide level in sea comprising:a guide tube having its lower open end immersed at least 0.5 m below the lowest tide level to minimize the undesirable effects of the current and surface waves, means for generating, processing and displaying the data signals, a transducer or a pair of transducers fixed substantially at the upper end of the guide tube for generation and reception of electrical as well as acoustical pulses, a switching circuit for isolating the transmitting and receiving signals, wherein at least one branch tube is provided near the upper end of the guide tube having its length determined by the formula L=(2nâˆ’1)&lgr;/4=(2nâˆ’1) C/4f â€ƒwhere n=1,2,3 . . . &lgr; is the wavelength of sound (meters); C is the velocity of sound (meters per second); f is the frequency of sound in Hz; and, the diameter of the guide tube is determined by the formula d10&lgr;ord<0.586&lgr;â€ƒ(where &agr;10=0.586) â€ƒwhere &lgr; is the wavelength of sound used, d is the diameter of the tube used for guiding acoustic pulse from the transducer towards the water surface and back.