CAT.No.CBM210E-3

Thermal Mass Flowmeter/Controller for Gas

MASFLO-OVAL Ⅱ
Supply system/Mixing process
Semiconductor production/Pilot plant
Measurement of Hydrogen/Ammonia

Mass Flowmeter(FHA)

Non-explosionproof

Mass Flow Controller(FHB)

Mass Flowmeter(FHC)

Explosionproof

Control Valve for FHC(FHD)[Measurement principle]
The gas introduced into the meter is divided into the sensor unit at a constant
proportion by laminar flow element.
Inside the sensor unit, a heater coil and temperature sensors loop around thecapillary in the center and both ends, respectively. These temperature
sensors constitute the bridge circuit.
When the gas that flows through the sensor unit remains still, heat supplied
from the heater is transferred to the temperature sensors on both sides
equally and the balance of the bridge circuit is maintained.
However, once the gas starts to flow, the difference occurs in the heattransferred to the temperature sensors, and an output proportional to themass flowrate is obtained from the bridge circuit.
By changing the branch-off proportion in the laminar flow element, thedesired flowrate range can be obtained.

Flowrate output signal
0 to 5VDC etc.
Amplification circuit
Power Supply±15VDC

Bridge circuit
Sensor unit

Flow direction

Laminar flow element (Bypass)MASFLO-OVAL Ⅱ MODEL: FHA/FHB

Non-explosionproof

Measure/Control accurately the flowrate of gas on a mass basis
FHB

FHA

FHA is a high accuracy,compact gas flowmeter
FHB is a flowrate controller that FHA isintegrated with a control valve(electromagnetic type)● Applicable to a wide range of flowrate, from 5NCCM (mL/min [normal]) to 500NLM (L/min [normal])● Optimal full-scale adjustment is available with the laminar flow element● Applicable to the most types of gas, except for high corrosive gas● Fast response● The control valve is of a normal close, electromagnetic type that ensures fast response and safe to use● Compatible with a variety of applications by combining with the readout unit
■ STANDARD SPECIFICATIONS■ PHYSICAL ORIENTATIONFHAConstruction

FHB●If the pressure is less than 1MPa

Non-explosionproof, for indoor use
1/8″, 1/4″, 3/8″,6mm, 12mm, 1/2″

Connecting tube
outer diameter

1/8″, 1/4″, 3/8″,6mm

Accuracy (※1)(including linearity)± 1% of FS (at actual gas calibration)

Reproducibility± 0.2% of FS

ResponseTopBottom

1 to 2sec (within ±2% of setting,
except for during zero startup)

1 to 3sec (time constant)○ Horizontal piping(transmitter on top)

× Horizontal piping(transmitter on bottom)△ Vertical piping

Operating temperature range −10 to +70℃ (no condensation)
Temperature effect± 0.1%/℃ of FS

Pressure effect

0.1%/0.1MPa of RD (N2), 0.01%/0.1MPa of RD (H2)

●If the pressure is 1MPa or more

Pressure loss (Air) (※2) 3.5 to 10.5 kPa
Zero stabilityMaterials

TopLong-term error: Max. 1%/year, Temperature drift: 0.05%/℃

Body

Major parts: SUS316 or equivalent

Seal

Fluoro-rubber (FKM): standard, Chloroprene rubber (CR),
Perfluoroelastomer (FFKM)

BottomPower supply±15VDC※1: Under normal circumstances, calibration is conducted using air or nitrogen gas withconversion factor compensation.
※2: Only for the body of the mass flowmeter; pressure loss for joint is excluded.

○ Horizontal piping(transmitter on top)

× Horizontal piping(transmitter on bottom)

× Vertical piping■ FLOW RANGE/MAX OPERATING PRESSURE
● FHA

● FHB

Model code

Full scale flow range
NL/min (at Air)
Minimum 0.0001 to 0.005
Maximum 0.00015 to 0.0075
Minimum 0.00015 to 0.0075
Maximum 0.3 to 15

0.99MPa

9.8MPa

19.6MPa

39.2MPa

FHA00S

FHA10S

FHA20S

FHA30S

FHA01S

FHA11S

FHA21S

FHA31S

FHA12S

FHA22S

FHA32S

FHA13S

FHA23S

FHA33S

Minimum 0.3 to 15
Maximum 2 to 100
Minimum 2 to 100
Maximum 10 to 500

Model code

Full scale flow rangeNL/min (at Air)

Maximum operating pressure (※1)

Maximum operating pressure

Minimum 0.00015 to 0.0075
Maximum 0.3 to 15

9.8MPa

19.6MPaFHB11SFHB21SKv value

1.1×10−5
to 6.6×10−2

Minimum 0.3 to 15
Maximum 1.4 to 70
Up to 100NL/min available with H2and Helium

FHB12S※1: Maximum operating pressure may be lower depending on connection specification andKv value of valve.
※2: If Kv value is 4.3 × 10−3 or more, maximum operating pressure is restricted at 10MPa.

※1: Maximum operating pressure may be lower depending on connection specification.

■ DIMENSIONS [Unit: mm]●FHA●Transmitter

FHB
Transmitter

47

47

D-SUB
connector

D-SUB
connector

MODEL

FHA20S/30S
FHA01S/11S
FHAB

A

FHA12S(L)

FHA22S/32S

Flow

Flow

FHA23S/33S
FHB11S/21S
FHB12S

B

B

CH

47

2525111

FHA13S

W

W

FHB

T

U

2-M4 (depth 5)(mounting screw)

T

U

T

U

W

37

516

47
50
75
75
92
92

55555521
23
28
40
2121103
72
91
108
135
102
117

4665
66
101
45
46

NOTE: Dimension L varies with joint size.
2-M4 (depth 5)(mounting screw)(L)

Body internal Weight
thread(kg)98

FHA21S/31S

(L)

AA

FHA00S/10S

BodyCCH

Body

HValve

46
65
66
101
45
46

132
151
152
187
142
143

129
148
176
202
159
174

IN：G1/4
OUT：G1/8
G1/4
G1/2
G1/4

0.3

1.2
2.9
3.1
9.1
2.0
2.1

MASFLO-OVAL Ⅱ MODEL: FHC/FHD

Explosionproof

Explosionproof structure which can be used for hydrogen gas
FHC is a hydrogen explosion-proof model of thegeneral-purpose gas mass flow meter FHA, and isavailable as a high-pressure gas certified product.

FHDFHCFHD is based on FHB with the control valve in thehydrogen explosionproof structure. In combination
with FHC, it makes up of the explosionproof thermal
mass flowrate controller for gas.
● JIS explosionproof construction model "d3aG4", that is applicable to hydrogen gas● Applicable to a wide range of operating pressure, from vacuum to 36.2MPa at the maximum● Applicable to a wide range of flowrate, from 5NCCM (mL/min [normal]) to 500NLM (L/min [normal])● Optimal full scale adjustment is available with laminar flow element● Applicable to the most types of gas, except for high corrosive gas● The control valve is of a normal close, electromagnetic type that ensures fast response and safe to use● Compatible with a variety of applications by combining with the readout unit
■ STANDARD SPECIFICATIONS■ FLOW RANGE/MAX OPERATING PRESSURE

FHC

FHD

1/8″, 1/4″, 3/8″, 3/4″,6mm, 12mm, 1/2″

Connecting tube
outer diameter± 1% of FS (at actual gas calibration)

Reproducibility± 0.2% of FSResponse

Maximum 0.00015 to 0.0075
Minimum 0.00015 to 0.0075Maximum 0.3 to 15
Minimum 0.3 to 15

1 to 2sec (within ±2% of setting,
except for during zero startup)

1 to 3sec (time constant)Operating temperature range −10 to +50℃ (due to explosionproof configuration) (no condensation)
Temperature effect± 0.1%/℃ of FS

Pressure effect

0.1%/0.1MPa of RD (N2), 0.01%/0.1MPa of RD (H2)Pressure loss (Air) (※2)

3.5 to 10.5 kPa

Zero stability

Long-term error: Maximum 1%/year, Temperature drift: 0.05%/℃

Materials

Kv value

Maximum operating pressure 39.2MPaMinimum 0.0001 to 0.005

1/8″, 1/4″, 3/8″,6mm, 12mm, 1/2″

Accuracy (※1)(including linearity)

Model code

Full scale flow range
NL/min (at Air)

Explosionproof configuration (TIIS、KCs)

Construction

Maximum 2 to 100
Minimum 2 to 100

FHC30S

FHC30S + FHD30S

FHC31S

FHC31S + FHD31S

FHC32S

FHC32S + FHD32S

1.1×10−5
to 6.6×10−2

FHC33S

Maximum 10 to 500※1: Maximum operating pressure may be lower depending on connection specification andKv value of valve.
※2: FHC series can be supplied as the certified product for the high pressure gas.
(Approved range is the body only. Detachable parts, such as double ferrule bite-type fitting,are not included.)

Body

Major parts: SUS316※3: FHD series functions as control valve by combining with FHC series.
FHD cannot be used by itself.

Housing

AC4C-T6※4: FHD series is available only if both full scale flow range and Kv value of valve are satisfied.

Seal

Fluoro-rubber (FKM): standard, Chloroprene rubber (CR),
Perfluoroelastomer (FFKM)※5: If Kv value is between 4.3 × 10−3 and 6.6 × 10−2, maximum operating pressure is restricted
at 10MPa.

Power supply±15VDC※1: Under normal circumstances, calibration is conducted using air or nitrogen gas withconversion factor compensation.
※2: Only for the body of the mass flowmeter; pressure loss for joint is excluded.

■ PHYSICAL ORIENTATION

TopBottom○ Horizontal piping(terminal box on top)

× Horizontal piping(terminal box on bottom)

× Vertical piping■ DIMENSIONS [Unit: mm]
●FHC●

E：245
168

BodyFHD

TerminalPressure-tightpartpacking gland

E：222144Terminal
Pressure-tightpart
packing gland

MODEL
FHC30S

Body

H

B

C

GHI

TUWh

Body
internal
threadWeight(kg)828230153

139

6860

1160

15

G1/45.0

1191388210067100

190
223

176
209

105
13860
70

11960
90

32
50

G1/2
G1/2

8.4
13.3

FHD30S
FHD31S

707045109132

6850

50

22.5

G1/43.8

FHD32S

70

7045

109

132

6850

50

22.5

G1/2

3.8

FHC31S
FHC32S
FHC33S

h

C

IChI

GH

G

FHC

A

B

TIIS: G3/4
KCs: M25×1.5

T
U

41W

TIIS: G3/4
KCs: M25×1.5AFHDA
FlowFlow

4-M5 (depth 7)(mounting screw)T

4-M5 (depth 7)(mounting screw)

BW

NOTE: 1. Dimension E is the approximate dimension based on HPN series pressure-tight packing.
2. Dimension A is the face-to-face dimension of the instrument. Actual dimension may differ
based on the joint to be used.
3. The height of pipe axis (dimension h) differs between mass flowmeter and control valve.

READOUT UNIT MODEL: ROU28S, ROU28C

Receiving Instrument for MASFLO-OVAL II

MODEL: ROU28S(0 to 5VDC only)

MODEL: ROU28C(4 to 20mADC/0 to 5VDC supported)● A small, lightweight receiving instrument with the basic functions required for measurement and control.
● Flowrate value, accumulated flowrate value and flowrate set-point can be switched to the display.
● A flowrate adjustment device and an external input switch are placed on the front, realizing an easy-to-use layout.
● As standard specifications, it includes external output (analog and pulse) and externalcontrol input functions. Therefore, flexibility of system design can be improved.
● By combining the readout unit with the MASFLO-OVAL II series, a flow measurement system can be easily
configured.
■ CONNECTION WITH A READOUT UNIT
Mass Flowmeter(FHA)

Dedicated cable C1
0-5VDC/
4-20mADC (※1)

Mass Flow Controller(FHB)

Commercially-available cable(ROU28C)

System equipment/ device<Extension device>

READOUT UNIT
(ROU28S)

100VAC

Control Valve(FHD)

0 to 5VDC (Within 30m from ROU)

Relay terminal block

4-20mADC (※1)

<Extension device>

READOUT UNIT
(ROU28S)

0 to 5VDC (Within 30m from ROU)

Dedicated cable C1(Within 10m)

Commercially-available cable(ROU28C)

4-20mADC (※1)

Hazardous area

Non-hazardous area

System equipment/ device

Mass Flowmeter(FHC)

100VAC※1: Only compatible with ROU28C• The specification as of September, 2024 is stated in this catalog. Specifications and design are subject to change without notice.
• All content of this catalog is copyrighted by OVAL Corporation. Any reproduction, partial or whole, of the content without permission from OVAL is strictly prohibited.

3-10-8 Kamiochiai, Shinjuku-ku, Tokyo 161-8508
Phone: +81 3-3360-5121 FAX: +81 3-3365-8605

https://www.oval.co.jp/english
2108 2409 - -- - 2108S