Patent GB-752496-A (GB)
Title: Method of measuring flow of fluid and installation and turbine for carrying it into effect
IPC: G01P5/07
Filed: 1954-04-29
Abstract: 752,496. Measuring rate of flow of fluid. SEMISA SOC. ANON. April 29, 1954 [May 13, 1953; Feb. 1, 1954], No. 12422/54. Class 40(1) [Also in Group XIX] In fluid flow integrating apparatus, Fig. 1, voltage pulses produced by a turbine electromagnetic generator pick-up 1 are amplified at 6 and then converted into short - duration rectangular pulses in a device 7 and these feed into frequency divider stages 8<SP>1</SP> . . . 8n (e.g. scale-of-two circuits) and the slow-rate pulses emerging from the last divider actuate an electro - mechanical counter 9 which therefore indicates total flow. The rectangular pulses from the device 7 also trigger a mono-stable multivibrator shown at 10 in Fig. 1 and in detail in Fig. 7 whereby the mean anode current of the normally blocked triode measured by milliammeter 11 indicates fluid flow-rate. The grid 43 of trigger triode 40 is biased from a point 42 on a voltage divider 47, Fig. 8, and the point 42 is varied automatically by temperature compensating resistance 45 and may also be varied by adjusting a specific gravity compensating resistance 46 so as to vary the duration of the multivibrator impulses through meter 11. The resistance 45 comprises a negative temperature coefficient resistance shunted by a fixed (temperature-independent) resistance. If desired the grid 43 may be biased for specific gravity compensation by using a changeover switch to select the required voltage. The counter 9 may totalize fluid flow in different conduits 2, 2<SP>1</SP> &c. Fig. 1, each having a turbine 1, 1<SP>1</SP> &c. with magnets 3, 3<SP>1</SP> (fixed in the turbine rotors) co-operating with fixed solenoids 5, 5<SP>1</SP>&c. to feed pulses into rectangular pulses producing devices 7, 7<SP>1</SP> &c. and the latter are connected appropriately into the frequency dividing stages 8 according to the volumes of fluid which have flowed per revolution of each turbine. Thus in the case of two turbines 1, 1<SP>1</SP> as shown performing P and 4P revolutions per litre 7<SP>1</SP> will be connected after two binary reduction stages, i.e. at the input of dividing stage 8<SP>3</SP>. The magnet 3 may be so positioned on the turbine 1 with respect to solenoid 5, Figs. 2 to 5 (not shown) whereby the character or polarity of the pulses delivered by solenoid 5 indicate fluid flow direction. Construction of turbine and voltage pick-up, Fig. 6. The turbine shaft 25 has conical ends 26 in ball thrust bearings 22 and is enclosed by a tube 27 comprising helical grooves 28 in which are engaged the turbine blades 4 and in one or more of the blades 4 there is inserted a magnetized element 3 so that as the turbine rotates magnetized element 3 induces a voltage in solenoid 5. The latter is housed in a hollow plug 32 which is screwed into the outer casing tube 10 and maintains in position a duct 14 adjacent turbine blades 4. The duct 14 is detachable so that different diameter ducts 14 may be fitted to vary turbine speed for given fluid flow. The casing tube 10 has threaded ends for screwing into the fluidcarrying conduit 2.