Kurimoto, LTD.

Orifice Butterfly Valve
Flow control valve to reduce cavitation and noise at high differential pressure

BT-1Q type

Kurimoto, LTD.

Orifice butterfly valve controls flow at high differential pressure
Characteristics
1. Anti-cavitation structure
Achieves flow control at high differential pressure by multiple distributed
nozzles which divide the flow at all opening degrees.

2. Low noise
Possible to modulate the flows at high flow rate without making noise.

3. Light and compact
More compact than sluice and globe valves by adopting the butterfly valve
structure.
Disc of orifice butterfly valve

4. Water sealing by rubber seatHas excellent water sealing, same as the JWWA B 138 butterfly valve.

Merit

1. Standard Butterfly valve
As the valve opens, a crescentshape opening gets bigger.
2. Multi-hole variable orificevalve

30%

60%100%30%60%

100%

30%

60%

100%

The breakdown of flow in to
multiple small jets reduces noiseand makes throttling more
effective with less cavitation,even as the valve opens up.
3. Orifice butterfly valve
Cavitation is suppressed bymultiple distributed nozzles
which divide flow and the valve
opens . This can achieve higher
performance than multi-holevariable orifice valves.

The disc of orifice butterfly valve can rotate 90 degrees.
The breakdown of flow in to small holes contributes to its high performance,same as the multi-hole variable orifice valve.

Kurimoto’s Orifice Butterfly Valve reduces noiseStructure
Hybrid valve combined with the structure of orifice valve and butterfly valve
Full guide type: Suitable for flow control at high flow rateBody

Half guide type: Reduces energy loss at full opening
FlangeMulti-hole guide
Full guide

Seat (Rubber seat)

DiscHalf guide

Cavitation reducing structure
While a standard butterfly valve causes cavitation because of the turbulence flow at the outlet side, theorifice butterfly valve can achieve less cavitation.

Cavitation

Standard butterfly valve
Flow direction

Cavitation

Flow image

Internal inspection photo

Flow image

Internal inspection photo

Orifice butterfly valve
Flow direction

Allowable inlet pressure HA
HA is the new measurement standard to select the most suitable valve, not the allowable cavitation
coeffiecient. The curve shows the inlet pressure applicable to the velocity against a certain outletpressure. HA helps to easily judge if the valve is feasible for the condition.

Comparison table of allowable inlet pressure (Outlet pressure = 10mAq)

Allowable
Inletpressure
HA[mAq]BT-1Q full guideBT-1Q half guide

Flow speed inside pipelines v[m/s]Comparison table of allowable inlet pressure (Outlet pressure = 5mAq)

Allowable
Inletpressure
HA[mAq]BT-1Q full guideBT-1Q half guide

Flow speed inside pipelines v[m/s]
The above figures are limited to the internal inspection which may vary depend on actual operating conditions.

Allowable cavitation figure
The orifice butterfly valve (both sides types) has good performance, same as the multi-hole valve.

Allowable

BT-DD Disc polyflow valve

BT-1Q Orifice butterfly(high performance type)valve (half guide)

Cavitation
FT-10 Multi-hole variable
Figurebutterfly valve
σα

BT-1Q
Orifice butterfly valve (full guide)

Opening degreeα[%]The above figures are limited to the internal inspection which may vary depend on actual operating conditions.

Noise reducing structure
BT-1Q reduces noise more effectively than standard butterfly valves.
At high flow speed, it has the same performance as multi-hole variable orifice valves.

Cavitation figure σ≒≒0.5Standard butterfly valve

BT-1Q
Sound

Orifice butterfly valvepressurelevel
S[dBA]
FT-10
Multi-hole variable orifice valve

Flow speed inside pipelines v[m/s]
The above figures are limited to the internal inspection which may vary depend on actual operating conditions.

Pressure loss coefficientOpening /both sides /one side

PressurelosscoefficientK

Full guide

Half guide

Opening degree (%)
The above figures are limited to the internal inspection which may vary depend on actual operating conditions.

Measurements

Unit : mm

DiameterDimension

Height

These measurements are for the electrically-operated type. Please contact us if you needmeasurements for other types. We can manufacture larger BT-1Q at your request.

WidthStandard Specification
Type of valve

BT-1Q

Structure

Multi-hole spherical disc (both sides type, one side type)

Diameter

200～1000 Please contact us for larger diameter

Pressure

4.5K, 7.5K, 10K

Material

Body:FCD450-10 Disc:SCS13,SUS304
Stem:SUS403,SUS420J2 Rubber seat:CR

Operation

Manual, Manual cap type, Electrical

FlangeJWWA B 138

Fluid

Tap water, Industrial water, Agricultural water

Checklist for selecting flow control valve
Diameter

Operation

Quantity

FlangeFluid

PurposeManual/Electric/other

Flow rate/Pressure/Water level

Hydraulic condition
Case1

Case2

Case3

Inlet pressure

mmm

Outlet pressure

mmm

㎥/s

㎥/s

㎥/s

Flow rate

Inlet pressure

Outlet pressure

Inlet pressure
Pump

Kurimoto, LTD.
VALVE DIVISIONTOKYO OFFICE: 16-2, Konan 2-chome, Minato-ku, Tokyo 108-0075, Japan
Phone: +81 3 3450-8523
E-mail: ke_oto@kurimoto.co.jp t_arima@kurimoto.co.jp
Website: http://www.kurimoto.co.jp/

Outlet pressure