Brooks Instrument BM01, BM02 Specifications

Data Sheet

DS-PD-BM 01-02-eng
March, 2008

Brooks® Models BM01 and BM02

Brooks® Oval Flowmeters, BM Oval Series
BM01 and BM02

FEATURES

• Low flow measure ment, 0.53 to 132 GPH
(2 to 500 LPH)

• Very low pressure drop

• Viscosity to 1000 Cp (Centipoise)

• High Accuracy, 1% rate or better

• 0.03% repeatability

• Only two moving parts

• Reed or solid state Hall Effect Switch

• ¼ inch female NPT standard

• Available in PPS or 316 Stainless Steel
(Hastelloy® C shaft option)

DESCRIPTION

The Brooks BM01 and BM02 are low flow positive
displacement oval flowmeters designed for
applications requiring the high accuracy measurement
of clean liquids with viscosities less than 1000 Cp.
Units are available with a pulse output from a Reed
switch or solid state Hall effect switch for remote
registration and/or totalization.

PRINCIPLE OF OPERATION

The oval meter is a positive displacement meter. As
the fluid being measured passes through the meter, it
rotates 2 oval gears in a measuring chamber to
displace a precision volume of fluid. A sensor detects
the gear rotation to determine displaced volume and
flow rate.

Fluid pressure rotates the oval gears, Figure 1. In
position 1, the fluid exerts a clockwise driving force on
Gear A.

Typical BM01 and BM02

There is no net driving force on Gear B. It is
perpendicular to the flow so the fluid forces are
balanced around the shaft. As the gears rotate to
position 2, the fluid begins to exert a force on Gear B.
At position 3, all the driving force is on Gear B. This
alternating driving force provides a smooth rotation of
almost constant torque.

The meter design minimizes the slippage between the
gears and the measuring chamber wall. As a result, the
oval meter is less affected than other designs by the
liquid's viscosity and lubricity.

Figure 1 Principle of Operation Chart

1

Brooks® Models BM01 and BM02

Data Sheet

DS-PD-BM 01-02-eng

March, 2008

SPECIFICATIONS
Capacities

Viscosity BM01 BM02

< 5cP 1.32 to 26 gph 6 to 132 gph

(5 to 100 lph) (25 to 500 lph)

5 to 1,000cP 0.53 to 26 gph 4 to 132 gph

(2 to 100 lph) (15 to 500 lph)

Performance

Accuracy: +/- 1%
Repeatability: 0.03%
Typical meter performance and pressure drop:
Refer to Figure 2.

Ratings

Maximum working pressure:

PPS body: 75 PSIG (500 KPAG)
316 SS body: 150 PSIG (1000 KPAG)
Consult factory for higher pressure options.

Maximum working temperature:

PPS body and/or Rotors (Gears): 176° F (80° C).
316 SS body and Rotors (Gears): 248° F (120° C).

Ambient Temperature: -4° F to 104° F (-20° C to

+40° C).

Outputs

Note: each meter contains both switch types

Reed Switch

Detection Method: Reed Switch, Two wire SPST N/O contact.
Max. Voltage: 150 VDC maximum.
Contact Capacity: 0.25 AMPS

Rating 3 Watts.

Termination: 39 inch (1 meter) flying lead.
Nominal K-Factor:

Model BM01: 1000 p/l (3785.4p/gal)
Model BM02: 400 p/l (1514.2 p/gal)

Hall Effect Switch

Detection Method: Hall effect switch
Response Frequency: 1,000 Hz maximum
Output Pulse: Unfactored voltage pulse

Input/Output = 4.5 to 24 VDC (4.6 ~ 9 mA)
Open Collector 25 mA output NPN compatible with

digital logic. Reverse power protection.
Termination: 39 inch (1 meter) flying lead
Nominal K-Factor:

Model BM01: 1000 p/l (3785.4p/gal)

Model BM02: 400 p/l (1514.2 p/gal)

Meter Materials of Construction

Meter Body: PPS (Polyphenylene Sulfide) or 316

Stainless Steel.
Rotors(Gears):

BM01 / BM02 - PPS or 316 Stainless Steel.

316 Stainless Steel only for High Viscosity.

Rotors (Gears) Bearings:

BM01 / BM02 - Zirconia
Note: (PPS Rotors No Bearings Required)

Rotors (Gears) Shafts: 316 Stainless Steel or Optional

Hastalloy® C (PPS body only).
O-Rings: Standard Viton® fluoroelastomers or Optional

Teflon®.

Connections

¼ inch NPT (female)

Dimensions

Refer to Figure 3. For certified dimensional prints, contact
the factory.

Pressure Equipment Directive (97/23/EC)

Equipment falls under Sound Engineering Practice
(SEP) according to the directive.

2

ORDERING INFORMATION

To order please specify:

1. Model Number

2. Product (Process Fluid)

3. Viscosity

4. Maximum Operating Temperature

5. Maximum Operating Pressure

6. Operating Flow Ranges (Min., Max., & Normal)

7. Accessories Required