Brooks Instrument Sho-Rate 65 mm Metering-Tube Family
About this part
R-2-65 designates a Brooks Instrument Sho-Rate metering-tube family associated with meter size 2 and the 65 mm Model 1350/1350G glass-tube variable-area flowmeter line. It is not a complete configured flowmeter model. Legacy manufacturer data documents R-2-65-5 with glass, 316 stainless-steel, or Carboloy floats, while current Revision G documentation identifies R-2-65-AG through R-2-65-DG. The complete tube number, float, scale, fluid, reference conditions, and meter model determine capacity and accuracy
Configurations vary. Verify the exact unit before choosing a replacement.
Device typeGlass-tube rotameter metering-tube family
Configuration statusConfiguration varies
Application classIndustrial automation and process equipment
CategoryFlow Control
Specifications
Identification
Manufacturer
Brooks Instrument
Product line
Sho-Rate
Identifier role
Metering-tube designation stem; not a complete configured flowmeter model
Associated meter size
Size 2
Compatibility
Associated meter line
65 mm Sho-Rate Model 1350, 1350E, and current 1350G generations, subject to the exact tube suffix and assembly model
Construction
Metering principle
Variable area using a tapered glass metering tube and spherical float
Metering-tube material
Borosilicate glass
Scale
Nominal scale length
65 mm for the associated Model 1350-series meter
Configuration
Legacy R-2-65-5 float selections
Glass, 316 stainless steel, or Carboloy
Current R-2-65-AG through -DG float selections
Glass, sapphire, 316 stainless steel, Carboloy, or tantalum; capacity depends on both tube and float
Operation
Spherical-float reading point
Center of the float
Installation
1350G meter orientation
Mount within 6° of true vertical with the inlet at the bottom
Performance
Legacy 1350/1350E meter-family accuracy
Standard ±10% of full scale; optional ±5%. This is an assembly/scale-level rating, not fixed by R-2-65 alone
Current 1350G meter-family accuracy
±5% at documented air or water reference conditions; exact scale and calibration selection must be verified from the complete model code
Repeatability by generation
Legacy 1350/1350E: 0.5% full scale; current 1350G: 0.25% full scale
Ratings
Associated meter-family pressure and temperature
Legacy 1350E and current 1350G documentation state 200 psig from 33°F to 250°F (approximately 13.8 bar from 1°C to 121°C). Verify the complete assembly and certification before applying this rating
Capacity
Exact flow range
Not determined by R-2-65 alone; use the complete tube suffix, float material, scale, fluid, and reference conditions
What Does R-2-65 Mean?
Brooks documentation establishes the identifier's application boundary but does not provide a character-by-character decoding of the R-2-65 stem.
Segment
Field
Interpretation
R-2-65
Tube identifier stem
Official Brooks tables associate this stem with meter size 2 and the 65 mm Model 1350/1350G line. The reviewed documents do not separately decode every character in the stem.
-5
Legacy tube suffix
The January 2005 capacity table uses the complete tube number R-2-65-5. The standalone meaning of 5 is not defined in that document.
-AG, -BG, -CG, or -DG
Current Revision G tube designation
Current 1350G documentation defines four distinct R-2-65 tube numbers. The A–D selection changes the tube capacity family.
Float and scale code
Separate full-meter configuration fields
The full flowmeter model code separately selects float material, accuracy class, and millimeter, linear, custom-decal, or percent scale. R-2-65 does not determine these choices.
Documented Legacy R-2-65-5 Configurations
These values apply only when the complete tube number is R-2-65-5. Normal-air capacity is stated at 0°C and 1.013 bar absolute for meter operation at 20°C and 1.013 bar absolute.
Float
Legacy Model Code
Full-Scale Normal Air
Direct-Reading Air Range
Direct-Reading SCFH Range
Glass
A1
4.29 ln/h
0.4–4.2 ln/h
0.01–0.16 scfh
316 stainless steel
A3
13.5 ln/h
1.5–13.5 ln/h
0.02–0.52 scfh
Carboloy
A4
22 ln/h
2–22 ln/h
0.04–0.85 scfh
Current 1350G R-2-65 Tube Matrix
Capacity spans show the lowest and highest full-scale values across the five documented floats; they are not universal ranges for every configured meter. Air SCFH values use 70°F and 14.7 psia reference conditions.
Tube
Full-Meter Tube Code
Water Capacity Span
Air Capacity Span
R-2-65-AG
G
0.010–0.10 gph
0.12–0.71 scfh
R-2-65-BG
H
0.014–0.14 gph
0.16–0.87 scfh
R-2-65-CG
J
0.12–0.70 gph
0.99–3.3 scfh
R-2-65-DG
K
0.68–2.7 gph
3.9–12 scfh
Selection and Service Boundary
Match the complete tube number and float material before using a capacity table or flow curve.
For a millimeter scale, the fluid, float material, tube revision, and applicable flow-curve data must agree.
Read flow at the center of the spherical float.
Dirt on the tube or float can cause inaccuracy or float sticking; Brooks permits cleaning the borosilicate tube with a solvent that does not attack glass.
After reassembly, follow the applicable meter-generation manual for leak testing and packing inspection.
