JPS649318A - Flowmeter - Google Patents

Abstract

PURPOSE:To facilitate a contact between a flowmeter and a fluid to be measured and increase a speed of response by detecting the temperatures of both the ends of an electronic cooling element and obtaining the flow rate of the fluid on the basis of a temperature difference between both the ends. CONSTITUTION:An electronic cooling element 1a and two temperature measuring elements 1b and 1c are arranged in the flow of a fluid so that a line connecting the two elements 1b and 1c to each other intersects with a fluid flow direction. When a constant current is supplied to the element 1a and the heating and endothermic values of both the ends of the element 1a are made constant, a temperature difference between both the ends changes depending on the quantity of heat taken away or given by the flow and the quantity of a change in the temperature difference relates to a flow velocity. Accordingly, the temperatures of both the ends of the element 1a are detected by the elements 1b and 1c and the flow rate of the fluid is obtained by a signal outputted from a measuring circuit 4 on the basis of a difference between the output values of the elements 1b and 1c. Thus, the elements 1a-1c can be formed on a substrate and a time for which heat is transferred from one end of the element 1a to the other and the temperatures or the heating and endothermic values of both the ends of the element 1a reach stationary states constitutes a speed of response.