tailieunhanh - MEMS Mechanical Sensors - Stephen Beeby Part 13

Tham khảo tài liệu 'mems mechanical sensors - stephen beeby part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 230 Flow Sensors Table Data for Commercial Flow Sensors Company Flow Range Sensitivity Response Time Fluid Operating Maximum Resolution Temperature Overpressure Robert Bosch 1 000 kg h Air -40 C to GmbH 73 120 C HL Planartech- Air -40 C to nik GmbH 74 120 C Fraunhofer Institute for Silicon 2-700 g s 2 ms Air Technology 75 HSG-IMIT 61 10ul h to 5 l h 4 mV K 5 ms Liquid slpm1 4 mV K 5 ms Gas Sensirion AG 150 nl min to 50 nl min 20 ms Water 10 C to 5 bar 62 1 500 ul min 50 C 1 nl min up to 50 ul min 50 ms Water 100 bar sccm2 sccm2 Nitrogen 2 bar bypass 100 Nitrogen 0 C to l min 70 C Leister 77 sccm2 2 ms Gas -10 C to 70 C 10 bar SLS Micro Tech- 000 mV ul 230 us Gas -20 C to bar nology 78 sccm2 with bypass 120 C GeSiM 79 1-70 ul min 100 uV ul min Water 40 bar Mierij Meteo m s 0 to 360 1 sec Air -25 C to 80 70 C 1 slpm standard liter per minute. 2 1 000 sccm 1 l min. pressure drop along a flow channel with known fluidic resistance Rf and calculating the flow Q from the fluidic equivalent to Ohm s law Q Ap Rf. It is comparable to measuring the current Q in an electric circuit by sensing the voltage drop Ap over a fixed resistance Rf . The sensor presented by Cho et al. 81 uses a silicon-glass structure with capacitive read-out Figure a . Fluid enters the chip through the inlet at pressure p1 flows through a channel and leaves the sensor with pressure pr If the flow channel is small enough to create a resistance to the flow a pressure drop Ap appears across the channel. The pressure above the membrane and the pressure at the inlet are kept equal. The pressure difference is measured by a capacitive pressure sensor which is switched at 100 kHz. Capacitive pressure sensing principles are also used in the devices described by Oosterbroek 82 83 . In addition a hybrid piezoresistive readout was fabricated. Two separate capacitive pressure sensors were used for the sensor shown in Figure b . This enables the .