Application
Use example

List ofproducts

Static pressure measurement◆Measurement of static air Monitoring of pressure inside room and alarm issuance(1) E xample of use in cleanroom

WO71

Fine differential
pressure gauge

The instrument is used to monitor thepositive pressure in a clean room. By
keeping the clean room under positive
pressure, inflow of air from the outside
is prevented.

HH
Positivepressure

PositivepressureH(2) E xample of use at factorythat handles hazardous
substances

WO81
H: high pressure side L: low pressure sideFinedifferential
pressureswitch

Fine differential
pressure sensor

MS61A-RAL

QDP33

L

Negativepressure

Negativepressure

Fine differential
pressure sensor

EMD8AL
Finedifferential
pressure switch

EMD7

EMT1

◆For internal pressure explosion-proof
When devices are used in an explosive
atmosphere, they are used after clean
air is supplied for a certain time until
the pressure stipulated by the relevant
law or regulation is reached.

MS99

MS99S

Fine differential
pressure gauge

The instrument is used to monitor
negative pressure. By keeping theinside of the factory under negative
pressure, leakage of air in the factory tothe outside is prevented.

FR51A

EMTGP1Fine differential
pressure switch

Instrumentation panel

Instrumentation panel

H

Explosive
atmosphere

H

Explosive
atmosphere

EMT1H

Fine differential
pressure sensor

EMT6

EMP5A

EMRT1

◆Liquid level gauge (air purge type)
A pipe is inserted into a tank, and a tiny
amount of air is released from the tip of
the pipe. At this point, as the pressure
inside the pipe reaches [liquid level
height × specific gravity of liquid], it ispossible to know the liquid level heightif the specific gravity of the liquid isknown.

Fine differential
pressure gauge
H

SuppliedairPressure- Throttle
reducing
valve
valve！

HWS15A
Rotor-type
flowmeter

Fine differential
pressure
sensor H

Insertion
pipehSuppliedairPressure- Throttle
reducing
valve
valve

Rotor-type
flowmeter
InsertionpipehAccessories
Application

Precautions
MaintenanceSelect the base, piping material, and other components in accordance with the use environment.

Caution114

Application

WO81

Use example
Static pressure measurement◆Measurement of flowing air Monitoring of ventilation/exhaust device and alarm issuance
Fine differential pressure gauge,
fine differential pressure switch,or fine differential pressure sensor

WO71

L

FR51A

MS99S

QDP33

EMD8A

EMD7

EMT1

EMTGP1

6D or higher

Positivepressure

Negativepressure

Fine differential
pressure switch

When the fan in an electric heater
stops during energization of the heater,
the fine differential pressure switch
is activated to stop all devices andprevents temperature rises and fusingof the heater.

Maintenance

H

Fine differential
pressure gauge
HH

Fine differential
pressure switch

Fine differential
pressure sensor

H(3) For control of airflow rate
in drying furnaces and tunnel
ceramic kilns
To keep hot airflow in an optimum
condition, the airflow is monitored via
the fine differential pressure switch,and once the airflow condition worsens,
an alarm is issued, or the hot airflow isshut off, and the device is stopped.

！
Caution115

Fine differential
pressure sensor

HEMRT1

Precautions

4D or higher

Straight
pipe part(1) For prevention of burnaccidents from an electricheater

EMT6

ApplicationStaticpressuretube

In measurements of static pressure inside a normal duct, because of turbulence, it may become difficult to read the value on a finedifferential pressure gauge as the pointer pulsates, or the measurement value is subject to error. Therefore, be sure to attach a staticpressure pipe to the straight pipe part with a determined length. Because the static pressure in the duct becomes positive pressure andnegative pressure before and after the fan, be sure to connect pipes by paying attention to the polarities of the bases (high-pressure side,low-pressure side) of the fine differential pressure gauge, fine differential pressure switch, and fine differential pressure sensor.

The fine differential pressure switch
detects incomplete combustion due toinsufficient exhaust and combustion
stoppage due to a failure of the air
blower, and issues an alarm.

Accessories

H

6D or higher

4D or higher(2) For monitoring of flueexhaust/burner air supply

HWS15AL

Straight
pipe part

EMT1H

EMP5A

Fine differential pressure gauge,
fine differential pressure switch,or fine differential pressure sensorAtmospheric pressure

Staticpressure
tube

MS99

MS61A-RAH

H: high pressure side L: low pressure sideD

List ofproducts

Fine differential
pressure gauge
LFinedifferential
pressureswitchLL

Fine differential
pressure sensor

Select the base, piping material, and other components in accordance with the use environment. The dimensions on the upstream side andthose on the downstream side differ depending on the duct shape. For details, refer to page 108.

Application
Use example

List ofproducts

Measurement of airflow rate and airflow speed

WO81◆Example of use for detecting airflow rate in ducts(1) F or Pitot tubes (overall/static pressure pipe)

H: high pressure side L: low pressure side

Fine differential
pressure gauge
LLH

H

Center ofduct

Overall/staticpressure pipe

Center ofduct

6D or higher

6D or higher

4D or higher

Straight
pipe part

4D or higher

Straight
pipe part

MS61A-RA

Fine differential
pressure gauge
HLH

L

Total
pressure pipe

Staticpressure pipe

Center of
duct

1D
6D or higher

Totalpressure pipe

Staticpressure pipe

1DQDP33
Fine differential
pressure sensorCenter ofduct

D

To obtain airflow rate/airflow speed
simply and at a low cost, use the staticpressure pipe and total pressure pipe
as shown in the figure on the right.

6D or higher

4D or higher

4D or higher

EMD7

EMT1

EMTGP1Fine differential
pressure gauge

LL

H

D

Fine differential
pressure sensor

EMT1H

EMT6

DOrifice

OrificeH

6D or higher

EMD8A

Straight
pipe part

Straight
pipe partA device that throttles a conduit inwhich air flows by means of a circularplate with a round hole is called anorifice. Narrowly throttling the conduit
increases the flow speed and reduces
the static pressure. At this point, bymeasuring the differential pressure
before and after the orifice, the airflow
rate is calculated.
*We do not handle orifices.

MS99S

D

(2) F
 or Pitot tubes (staticpressure pipe + totalpressure pipe)(3) For orifices

MS99

DOverall/staticpressure pipe

WO71

FR51A

D

When the airflow speed is faster than 2m/s, it is possible to detect the dynamic
pressure by installing a overall/staticpressure pipe and obtain the airflow
speed by a calculation formula (referto page107). When the maximum
airflow speed at the center of the duct
is obtained, it is possible to obtain theairflow rate by the formula [Maximum
airflow speed × Duct cross section area× 0.9].

Fine differential
pressure sensor

6D or higher

4D or higher

Straight
pipe part

4D or higher

Straight
pipe part

EMP5A

EMRT1

(4) F
 or composite Pitot
tubes

Fine differential
pressure gauge

By equally dividing a duct crosssection, installing a single Pitot tube
at the center of each division, andby gathering the total pressures andstatic pressures, respectively, of those
Pitot tubes, it is possible to extract theaverage total pressure and average
static pressure at the same time.
*We do not handle composite Pitottubes.
For details, make an inquiry to thecomposite Pitot tube manufacturer.

LL

H

H
Fine differential
pressure sensor

HWS15AD

Accessories
Application

D

Precautions
Straight pipe section

Maintenance

Straight pipe part！
CautionSelect the base, piping material, and other components in accordance with the use environment. The dimensions on the upstream side andthose on the downstream side differ depending on the duct shape. For details, refer to page 108.

116

Application

WO71

FR51A

MS99

MS99S

MS61A-RA

QDP33

Measurement of pressure loss

◆For detection of clogging of filters
By installing two static pressure
tubes, one each before and after
the filter, and measuring thepressure loss, it is possible to know
the degree of clogging of the filter.
Generally, a pressure range with its
maximum value ranging from 300
Pa to 1000 Pa is used.

H: high pressure side L: low pressure side
Fine diﬀerential pressure gaugeHLStaticpressure tube

Staticpressure tube

1DH

Staticpressure tube

Staticpressure tube

Air filter

Air filter
0.5DL

Fine differential
pressure sensor

DWO81

Use example

D

List ofproducts

0.5D

4D or higher

1D

4D or higher

6D or higher

6D or higher

Straight
pipe part

Straight
pipe part◆For transmission of the drive signal of automatic filters
When the filter is clogged andthe airflow rate decreases, thefine differential pressure switch
is switched. Switching of thefine differential pressure switch
energizes and starts the filter
winding motor to feed a new filter.

Fine differential pressure gauge
Fine differential
pressure switch

LHHLL

H

Finedifferential
pressure
sensor

EMD8A

EMD7

EMT1

EMTGP1◆For bug filter dust collectors
The fine differential pressure switch
detects the dust collection amountin accordance with the clogging
condition of the bug filter and thecycle, and operates the aeration
device to clean the bug filter.

Fine differential
pressuregauge

H

Fine differential
pressure switch

LH

Fine differential L
pressuresensor

LH

EMT1H

EMT6

EMP5A

EMRT1

HWS15AAccessories
Application◆For detection of the defrosting cycle of cooling coilIn the cooling operation, to prevent
attachment of frost on the coolingcoil and decrease of its function,
the fine differential pressure switch
detects the frost attachment amountand issues a defrosting operation
instruction.

Fine differential
pressure switchH

Fine
differential
pressure
LsensorL

H

Measurement of static pressure and pressure loss
◆For glove boxes

Instruments are used to control the inner pressure, and the target
object in the glove box is handled by means of a reacher. (Thefigure on the right illustrates a use example in which the pressurein the box interior is set to a negative pressure to prevent leakage
from the inside.)

Precautions

ExhaustFine differential
pressure gauge
L

Fine differential
pressure gauge
HL

Fine
differential
pressureswitchMaintenanceAir filter

Fine differential
pressure gauge
LL
Negativepressure！
Caution117

Select the base, piping material, and other components inaccordance with the use environment. The dimensions on
the upstream side and those on the downstream side differ
depending on the duct shape. For details, refer to page 108.

Reacher

Air filter

HWarranty■Warranty period
The warranty period for our product is one (1) year from delivery to the location specified by the orderer who makes a direct transaction
with us.

■Scope of warranty
If any failure or defect attributable to us becomes clear during the above warranty period, we will repair the product or supply asubstitute product free of charge. However, even during the warranty period, we will exclude the product from the scope of the warranty
if the failure or defect corresponds to any of the following:(1) The failure or defect was caused by an unreasonable condition, environment, handling, or usage not mentioned in theinstruction manual, specifications, and our product catalog.
(2) The failure or defect was caused by a factor other than our product.
(3) The failure or defect was caused by a modification or repair conducted by a party other than us.
(4) The failure or defect was caused by an event that could not be foreseen at the scientific and technical levels at the time of
product shipment from us.
(5) The failure or defect was caused by an external factor not attributable to us, such as acts of God and disasters.
Please note that the warranty mentioned here means the warranty for our individual product, and damage provoked by a failure or
defect of the product is excluded from the scope of the warranty.
*This warranty is valid only in Japan.

Application and usage
Our products are designed and manufactured as general-purpose instruments for general industries.
Therefore, our products are not intended for the following uses, and our products used in such a manner are outside the scope ofapplication.
(1) Equipment that is anticipated to greatly affect lives and properties, such as nuclear power generation, aviation, railways, marine
vessels, vehicles, and medical devices(2) Utilities that include electricity, gas, and service water(3) Use in outdoor locations and under similar conditions or environments other than those stipulated in the instruction manual(4) Usage to which considerable safety consideration and attention equivalent to (1) and (2) above need to be given

Service■Scope of service
Because the product price does not include service expenses, such as the dispatch of engineers, we will separately charge for theexpenses in the following cases:(1) Instruction for installation and adjustment and a witnessed test run(2) Maintenance inspection, adjustments, and repairs(3) Technical guidance and technical education(4) Witnessed inspections of products at our factory<<Note>> The product specifications and information in this catalog are subject to change without prior notice for product improvement orother reasons.

●For order placement, contact

Generalagent

Manostar Shop Co., Ltd.

1-2-3 Nishishiriike-cho, Nagata-ku, Kobe City, Hyogo 653-0031
TEL. +81-78-621-7000 FAX. +81-78-621-7788

ManufacturerYamamoto Electric Works Co., Ltd.

1-2-3 Nishishiriike-cho, Nagata-ku, Kobe City, Hyogo 653-0031
TEL. +81-78-631-6000 FAX. +81-78-631-6020

SEPTEMBER 2021 YAMAMOTO ELECTRIC WORKS CO., LTD., JAPAN