The Yoshitake MD-71-N emergency shutoff valve, along with the MD-71 model, is designed to automatically close and secure vital water supplies in the event of a significant earthquake. When a piping system is damaged by seismic activity, water stored in receiving tanks or gravity tanks can be lost. This emergency shutoff system prevents the interruption of lifelines by utilizing an earthquake sensor inside the KS-5 control console to automatically shut off the flow, effectively preserving water for living after a disaster. The MD-71-N model is JWWA compliant and is essential for adhering to national standards and guidelines for water preservation.

Specifications and Structure of MD-71 and MD-71-N

Model	MD-71 / MD-71-N (JWWA)
Application	City water
Applicable pressure	0-1.0 MPa
Applicable fluid temperature	5-60°C
Installation posture	Can be installed in any posture, from upright to sideways to horizontal piping.
Opening-closing time	50A and 65A: 3-4 seconds, 80A and 100A: 6-10 seconds, 125A and 150A: 12-17 seconds, 200A: 36-50 seconds
Actuator Rated voltage	24V DC
Actuator Power consumption	50-100A: MAX. 80 VA / 125-200A: MAX.120 VA
Actuator Ambient temperature	-20 - 55°C (no freeze condition)
Actuator Measure against dew condensation	Space heater contained
Actuator Manual operation	Manual operation mechanism provided
Actuator Protective structure	Outdoor rainproof structure (JIS C0920 IP65)
Actuator Wire lead-in port	G1/2
Material Body	FCD 450
Material Valve	Stainless steel or Stainless steel cast
Material Seat	FKM
Connection	JIS 10K flanged

INFO

Please contact us when using fluid is other than city water.

Dimensions and Weights

Nominal size	d	L	H	D	A	B	JIS10K C	JIS10K n-h	Weight (kg)
50A	52	41	332	115	175	160	120	4-19	7.7
65A	64	44	349	135	175	160	140	4-19	9.2
80A	78	44	356	145	175	160	150	8-19	9.7
100A	103	51	384	175	175	160	175	8-19	12
125A	129	54	406	206	175	160	210	8-23	16.5
150A	152	54	426	231	175	160	240	8-23	19.5
200A	200	66	550	291	175	160	290	12-23	31

Note: The shape of the 200A size is partly different from the standard figure.

Cv Value and Calculation Formula

50A	65A	80A	100A	125A	150A	200A
159	266	457	860	1320	2020	3540

$$ \mathsf { C v } = { \frac { 0 . 3 6 5 \mathsf { V } \sqrt { \mathsf { G } } } { \sqrt { \Delta \mathsf { P } } } } $$

P1 : Inlet pressure [MPa·A]
P2 : Outlet pressure [MPa·A]
∆P: P1-P2 [MPa]
G : Specific gravity (against water)
V: Max. flow rate of fluids [m³/h]
Cv: Cv value of each nominal size

Specifications and Structure of KS-5

The KS-5 control console serves as the automated command unit for the emergency shutoff system.

Model	KS-5
Number of emergency shutoff valves to be controlled	2 *1
Supply power source	85-240 V AC, 50 / 60 Hz
Ambient temperature	-10 - 50°C
Backup power source	24V DC
Backup time	Approx. 5 hours
Storage battery	Storage battery manufactured by Japan Storage Battery (PE 12 V 2.2)
Charging method	Constant charging method (float charging)
Measure against lightning	Surge absorber provided
Output terminal (For emergency shutoff valve control)	24V DC
Output terminal (For pump protection)	No-voltage c-contact (one c-contact) *2
Output terminal (For earthquake sensor external warning)	No-voltage a-contact (one a-contact) (ON contact when the earthquake sensor is working)
Output terminal (For power external warning)	No-voltage a-contact (one a-contact) (ON contact when the power inside the control console unusually drops)
Output terminal (Shutoff valve opening switch)	Pushbutton switch for resetting provided
Earthquake sensor (Detection direction)	All horizontal directions
Earthquake sensor (Setting acceleration)	200 Gal (equivalent to seismic intensity 5)
Installation place	Indoors / Outdoors (equivalent to JIS C0920 IP44)
Mounting method	Wall mounting

Footnotes

*1 Available with for controlling one, three or four emergency shutoff valve(s).
*2 It is different when controlling three or four emergency shutoff valves.

The figure shown above is a control console for controlling two emergency shutoff valves. The shapes of control consoles for controlling one, three, and four emergency shutoff valves are slightly different.

Features

1. An earthquake sensor (acceleration: 200 Gal) is installed inside the control console that automatically works in case of an earthquake (the shutoff valves close in intensity 5 upper).
2. The control console properly works with the backup power source even in case of a power failure.
3. The pump instantly stops when the shutoff valves close (this requires wiring between the interlock terminal of the emergency shutoff valve control console and that of the pump control console).
4. Resetting after a shutoff valve control is easy. (Just by pressing the shutoff valve opening switch.)
5. The control console can be manually operated.

Operation Flowchart (for Controlling Two Shutoff Valves)

Reference: What is Gal?

Gal Definition

One Gal is defined as an acceleration of 1 centimeter per second (1 cm/s²). That is, the gal can also be expressed as 1 centimeter per second squared. In the International System of Units (SI), the unit of acceleration is meter per second squared (m/s²), and 1 Gal is equal to 0.01 m/s². Although the gal is a non-SI unit, Japan's Measurement Law permits the use of Gal and Milligal (mGal) only for the measurement of gravitational acceleration as well as vibration acceleration regarding earthquakes.