Patent ID: 6435041
Filing Date: 2002-08-20
Classification: G01F

Abstract:
A device for measuring flow rate of cryogenic liquid flowing through a tube, comprisinga first tube and a second tube placed co-axially to form a co-axial tube and having an air-free space between the two tubes; said co-axial tube having both ends closed; said air-free space being filled with an insulating material; the co-axial tube being provided with a segmental opening with sealed ends to accommodate a close-ended hollow cylinder having its upper surface profile matching with that of the first tube; a conducting strip having one end thereof connected to a bottom surface of the hollow cylinder, and the other end being in contact with a stretched potentiometer wire to form a junction of two arms of a Wheatstone bridge; the conducting strip being rotatably fixed by a hinge, a support and a fixed frame whereby the upper surface of the hollow cylinder is flush with an inner wall of the first tube and allows lateral movement of the hollow cylinder due to drag force of cryogenic liquid flow; the two ends of the conducting strip being insulated from each other by an insulating block; the conducting strip being provided with a first co-axial coil between the hinge and the potentiometer wire contact end; one end of the first coil being connected through a slackening wire to one end of a second co-axial coil fixed on to the frame through an insulating block; the frame having two insulators fixed onto it supporting the stretched potentiometer wire; the frame, the conducting strip, the potentiometer wire and the coils being enclosed in a dual walled, jacketed, and insulated casting so that two ends of the potentiometer wire, a portion of the conducting strip between the insulator and the contact end and free ends of the co-axial coils are electrically connected to the Wheatstone bridge and a microprocessor unit.