Flow Control
5851I
Brooks Instrument Thermal Mass Flow Controller
About this part
5851I is the Brooks Instrument Model 5851i thermal mass flow controller for gas flow measurement and control. The official Brooks 5851i installation and operation manual identifies the model as a mass flow controller with a flow sensor, control valve, and integral electronic control system. Stored Sonisys auction history shows configured examples for air at 50 SLM, air at 80 SLPM, carbon dioxide, oxygen, and fully coded 5851IA variants
Unit-specific configuration
Observed configuration
Historical listing records identify this part as Air at 50 SLM. Exact gas, range, fittings, valve configuration, and communication interface must be verified from the physical unit label.
Configurations vary. Verify the exact unit before choosing a replacement.
Key Facts
ManufacturerBrooks Instrument
Part number5851I
Product familyConfiguration-specific
Device typeMass Flow Controller
Observed gasAir
Observed full-scale range50 SLM
Configuration statusVerify from unit label
Application classLife sciences and laboratory automation
CategoryFlow Control
Specifications
Identification
| Part identifier | 5851I |
| Device type | Thermal mass flow controller |
| Official model name | Brooks Model 5851i Mass Flow Controller |
Function
| Control architecture | Brooks documentation describes the 5851i as a flow sensor, control valve, and integral electronic control system |
| Control purpose | Accurately measures and rapidly controls gas flow in manual, electronic, or computer-controlled gas handling |
Features
| Fast response control | The 5851i manual lists fast response control for rapid gas settling with little or no overshoot or undershoot |
| Soft start | The 5851i manual lists soft start flow ramping for processes that cannot tolerate rapid flow transition |
| Valve override | The 5851i manual lists valve override to fully open or close the control valve independent of the command setting |
| Low command valve inhibit | The 5851i manual lists automatic shutoff that prevents the valve from opening when the setpoint is below 2% of full scale |
| Serviceable sensor | The 5851i manual identifies a removable cleanable sensor |
Flow
| Standard range | Brooks 5851i documentation lists any full-scale flow rate from 10 SLPM to 100 SLPM nitrogen equivalent |
| Hydrogen range context | Brooks 5851i documentation lists up to 200 SLPM hydrogen |
| Stored air configurations | Stored Sonisys records include air configurations at 50 SLM and 80 SLPM |
| Additional observed gas media | Stored and listing evidence includes carbon dioxide, oxygen, and air configured 5851i units |
Performance
| Accuracy | Brooks 5851i documentation lists +/-1% full scale including linearity at calibration conditions |
| Repeatability | Brooks 5851i documentation lists repeatability of 0.25% of rate |
| Response time | Brooks 5851i documentation lists less than 6 seconds response to within 2% of full-scale final value for a 0 to 100% command step |
| Control range | Brooks 5851i documentation lists 50:1 control range |
| Mounting attitude sensitivity | Brooks 5851i documentation lists +/-0.5% maximum full-scale deviation after rezeroing |
Temperature
| Operating ambient range | Brooks 5851i documentation lists 5 C to 65 C / 40 F to 150 F operating ambient limits |
| Non-operating ambient range | Brooks 5851i documentation lists -25 C to 100 C / -13 F to 212 F non-operating ambient limits |
Pressure
| Working pressure | Brooks 5851i documentation lists 1500 psi / 10.342 MPa maximum working pressure |
| Differential pressure | Brooks 5851i documentation lists 10 to 50 psi differential pressure, with higher values allowable depending on gas and range |
Electrical
| Power requirements | Brooks 5851i documentation lists +22.5 to +28 Vdc power, 370 mA at +28 Vdc |
| Command input | Brooks 5851i documentation lists jumper-selectable 0-5 Vdc command input or 4-20 mAdc command input |
| Output signal | Brooks 5851i documentation lists 0-5 Vdc output into 2000 ohms or greater, with jumper-selectable 4-20 mAdc or 0-20 mAdc output |
| Reference output | Brooks 5851i documentation lists 5 V +/-0.2% reference output with 1 kOhm maximum load |
| Connector | Brooks 5851i documentation lists a D-Type 15-pin DA-15P connector |
Leak integrity
| Leak integrity | Brooks 5851i documentation lists 1 x 10^-9 atm scc/sec helium leak integrity |
Mechanical
| Mechanical compatibility | Brooks 5851i documentation describes the mechanical connection as interchangeable with most popular mass flow controllers |
Configuration
| Configured-unit rule | Gas calibration, full-scale flow, fittings, valve state, electrical I/O selection, and installed system compatibility vary by full configured model code and unit label |
Applications
| Application domain | Gas handling in laboratory, analytical, process, industrial, and equipment-control systems |
Documentation Downloads
Local PDF copiesPart Photos
11 imagesHistorical archive images for identification, labels, connectors, and condition reference, not current inventory.
Historical Listings & Prices
Historical listing data, not a current offerArchive records14Tracked historical listing records
Historical median price$595.00Based on archived listing records
Recorded price range$130.00 - $1,016.40Low to high recorded listing price
Local documents1PDF copies available from Sonisys
Recorded price context
The typical recorded price range is $245.00 to $1,016.40. Based on 14 archived listing records; not a current offer, appraisal, or confirmed sale price.
View archived listing titles
- Brooks Instruments 5851I Mass Flow Controller w Calibration Paper 50 SLM Gas Air
- Brooks Instrument 5851i Carbon Dioxide Analog Thermal Mass Flow Controller
- Brooks Instrument 5851i Air Mass Flow Controller 80 SLPM S/N: 0199070107546001
- BROOKS INSTRUMENT 5851I MASS FLOW CONTROLLER T258202
- Brooks Instrument 5851i Oxygen Analog Thermal Mass Flow Controller
- Brooks 5851i Mass Flow Controller - Air, 50 SLM, Stainless Steel, 1/4" Ports, Te
Archived listings
Other Part Numbers & Aliases
5851IBrooks 5851IBrooks Instrument 5851IBrooks Model 5851iBrooks 5851i MFCBrooks 5851i Mass Flow Controller5851IA1BU2F2DEA5851IA1BT2H2DEA