Saturday Sept 16, 2006

Transcription

1 Saturday Sept 16, 26 Update on hardware 11:55 12:15 Varian V81M released July 26 A replacement for the V7LP V81M (not V81T) 5% reduction in power. -lower bearing temperature. Slightly higher pump speed. Higher tolerance to foreline pressure. All future AMS systems will use the V81 1

2 Comparison of pumping speed for V7LP and V81M Pump Pin (mbar) Power (W) S (L/s) V7LP 75k 7.52x N2 V 81-M-75k 7.52x V 81-M-8k 6.98x V7LP 9.71x He V 81-M 7.84x Ar V 81-M 7.13x Data from Varian V81M Upgrade Issues Varian has an upgrade program to exchange a V7LP for a new V81M. New V7LP pumps are no longer available but rebuild/exchanges are still supported. Electrical and roughing port are the same style and location as V7LP. V81 does require a new cooling fan mounting bracket. The V81 PCB controller has the same electrical connections and mounting holes as the V7 PCB controller. The V7 PCB controller WILL drive the V81M pump at slightly reduced speed (75 KRPM vs 8 KRPM). 2

3 Operating with V7 controller will slightly reduce best performance V 81-M: Compression ratio 1.E+1 1.E+9 8 KRPM 1.E+8 1.E+7 Compression ratio 1.E+6 1.E+5 1.E+4 75 KRPM 1.E+3 1.E+2 1.E+1 1.E+ 1.E-1 1.E+ 1.E+1 1.E+2 Foreline pressure (mbar) Ar N2 N2-75 He Data from Varian New Pump Controller Interface Improved control and diagnostics of the vacuum pump system Diaphragm pump Turbo Pumps Total DC current consumption Inlet pressure (auto start) PC control through USB with data logging capability Older systems are upgradeable 3

4 G1 aircraft ctof with new pump control system Controller has a 4x2 character LCD with a 3-fxn data entry knob and a USB port for PC control. Successfully operated on G1 aircraft in MaxMex 26 Turbo Pump Status and Error Messages Pump status, pump speed, bearing temperature (and controller), and current are continuously updated. Pumps Status Stopped Interlock Starting Auto Tune Braking Normal Error Pump Errors No connection Pump over temp Controller over temp Power fail Normal start fail Soft start fail Short circuit Too high load 4

5 PC Software interface for Pump Controller Pump Current (ma) Pump Current P2 V31 P3 V7 P4 V7 P5 V31 P6 V7 Diagnostic plots 11: AM 1/19/26 12: PM 1: PM 2: PM 3: PM 4: PM 5: PM Date/Time PumpStats_Jan19.pxp 35 Pump Temp (C) MD1Spd P(torr) : AM 1/19/26 P2 V31 P3 V7 P4 V7 P5 V31 P6 V7 12: PM 1: PM 2: PM 3: PM 4: PM 5: PM Date/Time PumpStats_Jan19.pxp BoxTemp TotalAmps Baratron C:\DATA PARTY\FieldWork\G1_Veracruz6\G1TestFlight_Pasco6 MD1Speed Pump 3 runs warmest Pump 3 has highest failure rate TotAmps 1 BoxT(C) : AM 1/19/26 12: PM 1: PM 2: PM 3: PM 4: PM 5: PM Date/Time PumpStats_Jan19.pxp 5

6 Consider Water Cooling Turbos in Warmer Operating Environments Since we now know that P2 (V31) and P3 (V7) run warmest water cooling these may be beneficial. Water cooling all turbos is probably not necessary. Startup behavior Pump Current (ma) Pump Current P2 V31 P3 V7 P4 V7 P5 V31 P6 V7 22 1:4 AM 1/19/26 1:42 AM 1:44 AM 1:46 AM 1:48 AM 1:5 AM Date/Time PumpStats_Jan19.pxp P5 load increases when filaments are turned on Fil ON Pump Current (ma) Vaporizer on Pump Current P2 V31 P3 V7 P4 V7 P5 V31 P6 V7 1:3 AM 1/19/26 11: AM 11:3 AM 12: PM 12:3 PM Date/Time PumpStats_Jan19.pxp 6

7 Electronics needs to be redesigned for TOF systems Only chopper, vaporizer and heater bias are need for TOF Power supply can be redesigned for TOF system 24 VDC supply (4A) in a 1U RM size 7

8 Constant Pressure Inlet System Important for use on aircraft. Eliminates variation of particle velocity and particle transmission calibration as lens pressure changes with altitude. Past and current efforts have been made by Ann Middlebrook (P3) Jose Jimenez (C-13/HIAPER) Jonny Crosier (BA 146) J. Jayne (G1) Compact pressure controller system Houses small pump, electronic valve and PID controller 8

9 Calculated Pressure Altitude relationship 6x1 3 Altitude, ft HIAPER_maxAlt MexCity_Alt_ft G1_alt 1 1 2x Pressure, torr SeaTacFlightMex26.pxp G1 Max. altitude 17, ft ~42 torr (for MaxMex) HIAPER max. altitude 51, ft Schematic of test setup to evaluate pinhole sizes, pressures and flows P1 P2 4 torr ~= 17K ft P3 Standard Lens 13 um SPI #8 Okeefe Regulate P1 to 1.3 torr Controller acts on lens pressure Proportional Solenoid / PID control KNF UNMP5 pump Needle valve to simulate altitude Flow measurement Feb 4, 26 Okeefe # cc/m measured under choke flow conditions For Plens=1.28 torr (controller set point), P2 =42 torr. 9

10 Evaluation of pressure regulation range Flow (cc/min) um, Set point=1.26 Plens_b #1 Okeefe Plens_c #5 Okeefe Plens_d #8 Okeefe. Plens_e #16 Okeefe Flow_d #8 Okeefe 1.8 P lens (torr) P ambient (torr) I choose the green points, Okeefe #8 Aerosol transmission tests were performed using this plumbing arrangement. QAMS, standard lens, 215 series chamber. From DMA/dilution system 13 um SPI.8 Okeefe 1

11 Collection efficiency measured by direct count method. 1 AMS (#/cc) Dmob NH4NO3 (1.41 torr lens, 13um SPI) ams_3nm ams_35nm ams_4nm ams_25nm ams_2nm 1:1 line unkown Okeefe measure 353 cc/m = #8 (.8") CPC (#/cc) Used QAMS standard lens, 215 series chamber, Pressure Controlled inlet, Plens=1.41 torr. The two plots are the same data, one has normalized Y-axis Collection efficiency. Measurement of polydisperrse NH4NO3 using standard 1um pinhole assembly and pressure controlled inlet. Aerosol concentration kept ~constant at (3.5-4.)e4/cc. This figure suggests that there are no significant losses in PC inlet. Sig_p46 Avg Standard 1 um pinhole 5 Sig_p46_R231_R23_avg Press Controlled Okeefe Hi 4 Sig_p46_R234_R235_Avg 4 Press Controlled Okeefe Low 4 Sig_p46_R228_R Dva 6 Polydisperse NH4NO3 sampled by 3 different configurations: 5 4 Standard 1 um pinhole Sig_p46_R231_R23_avg Press Controlled Okeefe Hi Sig_p46_R234_R235_Avg Press Controlled Okeefe Low Sig_p46_R228_R233 1) Standard 1um pinhole assembly 2) 13 um pinhole with Okeefe ¼ tube orifice at upstream end (high) Sig_p46 Avg 3 2 3) 13 um pinhole with Okeefe ¼ tube orifice at downstream end Dva 11

12 Pressure Controller Summary Determine lowest pressure range for operation select pinholes and pump. Use the lens pressure as the pressure to regulate. Eliminates a second pressure gauge For sampling pressures >~4 torr losses seem to be small. For sampling pressures <~4 torr losses may be significant. Need to design better sampling interface to minimize losses. Application: tunable pressure lens Direct Probe GC Inlet Designed for Dr. Akiama at Japanese Automobile Research Institute (JARI) Allows use of TOF spectrometer to measure effulents from GC capilary column 12

13 Cartridge heaters inserted in this block St. St 3/4OD tube for thermal isolation Teflon ferrule used here Copper-Stainless steel braze joint Thermal isolation 24 gauge (.16 ID x.22 OD) st. st. capillary tube extends from GC column connector thru the entire length of the copper rod, makes a 9 degree bend upwards to direct fused silica column effluent to ionizer. The silica column is inserted into the st. st. column which provides ease of assembly, alignment and (good?) thermal contact with the heated copper pieces. GC column connector St. st. capillary column extends to the face of this connector 13

14 Two step insertion process. Insert probe from the rear with vertical copper piece removed. Vertical copper rod is installed after inserting probe. Note steel capillary tube is bent horizontal for insertion from rear of AMS. Vertical copper rod is installed from top of chamber, access thru VUV port is helpful. Note steel capillary tube is now vertical, directing gas to ionizer. Stainless Steel capillary 24 gauge..16 ID x.22 OD (hard to see in photo) Make No contact between copper rod and Al. cylinder Thermocouple location for temperature regulation 14

15 Slide GC column inside of steel capillary column until it won t go any further this is where the st. st. column bends 9 deg. Upward into ionizer. Hand tightened brass nut with vespel ferrule for a leak tight seal. I used an RGA on detection chamber to test for leaks as the system was heated Flow measures 17.6 cc/min at entrance end of column. V31 at.88 amps ok (.34 amps no load) 15

16 Heating scheme. Two cartridge heaters (3/16 OD x 1.5 L 2 W 12 VAC ) inserted into copper block. With insulation, achieved 18C. Need a bit more power will get new higher power heaters. No leaks These 2W heaters have been replaced with two 1W ¼ OD heaters.plenty of power PID controller ¾ OD St.St. tube thermally isolates from chamber. Nov. 29, 25 1W heaters tested max temperature tested was 25C. Measuring of temperature gradient between heater block and probe temperature. For temperatures >2C you may need to cool the ¾ St. St. tube with either a heat sink or a small fan. 16

17 Minimal temperature losses 3 25 This shows that there is essentially no temperature gradient between the heater block and the probe temperature, ie no heat losses. Initial set pt was 1C. Changed to 25, which also equilibrated (but not shown). Note large overshot on heating block...the PID algorithm needs to be tunned (see Newport controller manual for proceedure). temp (C) 2 15 T_Probe T_Block 1 Controller Set Point = point number (~time) Dr. Akiama s Direct Probe results with VUV photo ionization.1.1 Response (a) Acenaphthylene Response (d) Chrysene Retention time (min) m Retention time (min) m Response (b) Fluorene Response (e) B[a]P Retention time (min) m166.1 Response Retention time (min) m (c) Phenanthlene (f)b[g,h,i]p Response Retention time (min) m Retention time (min) m276 17