Accessories
Pitot tube
List ofproducts

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φ34±0.3

Itemnumber

PTK‒□□6PTF‒6Details of flange set
MS99ĳ KROH
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MS61A-RA

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NameMaterialPTS‒□□6PTT‒□□6Q’ty

FlangeSteelt1．
61Flange packing

NBRt1．
01Pitot tube packing

NBRt1．
01

PTK‒VT4PTF‒4PTS‒VT4PTT‒VT4Overall/static pressure pipe For overall/static pressure measurement in measurement of airflow rate/airflow speed (dynamic pressure) in pipes
For vinyl pipe

QDP3335

49LHZ$

φ88R1

EMD8A

L

φ7MS99S

Applicable Pitottube

EMD7112

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48

EMT1
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EMTGP12YHUDOOSUHVVXUH
VLGHEDVH

WO71

Flange set to be mounted on Pitot tube

45

WO81

RoHS

φ40

9LHZ$$LUIORZGLUHFWLRQ

EMT1H

The length can be adjusted by moving the flange.

EMP5A

For metallic pipe

Item number

Ｌ (mm)

PTTS‒VT6‒300‒S300

PTTS‒VT6‒500‒S

500

PTTS‒VT6‒800‒S800

L

8R19LHZ$112

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48$LUIORZ

Precautions

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Maintenance

φ50

39φ8

HWS15A

Accessories

Stainlesssteel

φ10．
536

4EMRT1

Material Panel cutting

φ6±0.1

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The length can be adjusted by moving the flange.

105

Item number

Ｌ (mm)

PTTS‒MT6‒300‒S300PTTS‒MT6‒500‒S500

PTTS‒MT6‒800‒S800

Material Panel cutting
Stainlesssteel5φ10．

Accessories
Pitot tube
RoHS

Overall/static pressure pipe For overall/static pressure measurement in measurement of airflow rate/airflow speed (dynamic pressure) in pipes
Dimension drawing

Characteristics brought by inclination ofoverall/static pressure pipe

64
φ8

1.00°

10°20°

MS99

MS99S

30°

40°

MS61A-RA

0.9d / D=0.5

0.80.6

φD0.7

QDP33
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WO81

WO71

The ratio between the pressure generated
when the tip straight pipe part of theoverall/static pressure pipe is set inparallel to the airflow and the pressure
generated when it is inclined against theflow direction is shown in the figure below.
When the inclination angle is 10° or less,the pipe can be used without problems.

2YHUDOOSUHVVXUH
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List ofproducts

EMD8A

0.50.4EMD7EMT1

Pressure detector

EMTGP1

Static pressure hole (construction at the customer)<Reference drawing>

φd=2‒6≥2d$LUIORZ○	Static pressure hole is a hole orthogonally made inthe pipe wall.
○	As the hole diameter is greater than the staticpressure pipe diameter, this hole is useful for air
with a lot of dust and when the pipe diameter issmall.
○	Although the structure is simple, it is inappropriate if
the pipe wall is thin.

EMT6EMP5A

EMRT1！ Precautions on use of pressure detector○	Install the static pressure pipe, total pressure pipe, andoverall/static pressure pipe (Pitot tube) such that the tip
straight pipe part is in parallel (10° or less) to the airflow
direction.
○	If a pressure detector is used for measurement of thincorrosive mixed gas, use such a pressure detector thatis made of stainless steel or other materials capable ofwithstanding those gases because the materials to becorroded differ depending on the type of the gas.
○	When installing a pressure detector, provide the necessary
straight pipe parts in the frontward and/or rearward flow
directions in the duct.

EMT1H

HWS15A○	In airflow rate/speed measurements, conduct design andcalculation such that the necessary detection airflow speed
is over 2 m/s, and then check the actual airflow speed.
As the detection pressure to be generated at an airflow
speed of 2 m/s is approx. 2.5 Pa, it is difficult to measure
an airflow speed of 2 m/s or below at a high accuracy. If theairflow speed falls below 2 m/s, narrow the duct cross section
until the airflow speed at the pressure detection part reaches
the necessary value.
○	All pressure detectors are not suitable for detection with aircontaining much dirt and dust and air containing oily mist.
If a pressure detector needs to be used with such air out ofnecessity, occasionally dismount the detector and clean it.

Accessories
Application

Precautions
Maintenance106

Accessories
List ofproducts

WO81

How to use the Pitot tube
Measurement method of static pressure and dynamic pressure
Measurement method of static pressure

WO71

FR51A

MS99

MS99S

MS61A-RA

QDP33

EMD8A

EMD7

EMT1

EMTGP1

EMT1H

EMT6

EMP5A

1. Method using static pressure pipe
2. Method using a static pressure hole, which is asmooth hole made along duct inner wall so that noprotrusion into the duct is made3. Method using pipe (simplified Pitot tube) at an
orthogonal angle to the duct inner wall. However, touse this method, the flow speed must be 1 m/s orbelow. If the flow speed is higher than that, the error
will be greater because of the influence of the dynamic
pressure.

Diagram for explanation of total pressure, staticpressure, and dynamic pressure

Pt

Measurement method of dynamic pressure
To know a flow speed, only measuring the dynamic
pressure of the flow obtains it. However, the dynamic
pressure cannot be directly measured. Therefore, use
the formula below.
Total pressure − Static pressure = Dynamic pressure
The dynamic pressure can be obtained from thedifferential pressure between the pressure at the totalpressure pipe and that at the static pressure pipe.
1. Method of installing static pressure pipe and total pressure
pipe at a distance D between them. (Refer to page 116)
2. Method of installing overall/static pressure pipe

Measurement method of static pressure and dynamic pressure
The measurement method for flow speed using the Pitottube is relatively simple and highly reliable, but as the airflow
speed decreases, the detection pressures (total pressure,static pressure) and the differential pressure (dynamicpressure) between them also decrease, and accurate
measurement is disabled at an airflow speed of 2 m/s orlower.

Airflow speed - dynamic pressure relationship table
30

100 ℃

Calculation formula of flow speed by means ofthe Pitot tube
V（m/s）＝

Precautions43

ρ＝1.293 kg/m3

10710203040 50 60

7080 10090200300

400 500

Total pressure − Static pressure = Dynamic pressure (Pa)

Measurement of airflow rate by means of the Pitot tube
○ Set the tip straight pipe part of the Pitot tube inparallel to the flow. As the measurement points,
set the 10 points on each of two diameter linesthat cross each other at the right angle on themeasurement pipe cross section, 20 points in total,
as shown in the formula on the right. However, as
this method requires substantial time and effort, it
is not suitable for commercial use.
○ Use of a composite Pitot tube, in which Pitot tubes
in large number are used, is convenient.
○ Method to obtain approximate flow rate bymeasuring the maximum airflow speed at thecenter of pipe with a single Pitot tube
Flow rate = Maximum airflow speed × Pipe crosssection area × 0.9

Measurement points
in Pitot tube

Composite Pitot tube

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SRLQW

Rr3
r4

r5

Maintenance

50 ℃

765r2

Application

0℃$LUIORZ10VSHHG 9PV 82
ρ （Pt－Ps）

Where,
ρ: Fluid density (kg/m3)
Pt: Total pressure (Pa)Ps: Static pressure (Pa)
Density of dry air at 0°C and one atmosphere

200 ℃

20

r1

Accessories

PdPt (total pressure) = P
 s (static pressure) +Pd (dynamic pressure)

EMRT1

HWS15APs

r1＝0．316R
r2＝0．548R
r3＝0．707R

r4＝0．837R
r5＝0．949R

NEW AEROEYE*NEW AEROEYE is a product manufactured andsold by Wetmaster Co., Ltd.

Accessories
How to use the Pitot tube

List ofproducts

Guide for Pitot tube installation location

WO81

Depending on the pipe layout, the flow may be disturbed, which may affect the measurement accuracy.
Therefore, when installing a Pitot tube, we recommend securing a sufficient straight pipe length equal to or greater than thecorresponding value in the table below.
P

D: Duct diameter
Round duct
D = duct inner diameter
Pitot tube installation location
D = (duct inner width + height) / 2
Square duct

L1

L1

L2

Dimension on
downstream side(L2)90° bend orsingle tee

6D

4D

L2

MS99S

MS61A-RA

P

L1

FR51A

MS99

PP

Dimension on
upstream side
(L1)
Without flow
straighter

WO71

Two or more
90° bends
on the sameplane

L2

10D

4D

QDP33

EMD8A
Two or more90° bends
on different
planesP

L1L2（PP

L1L2

L1L2P

L1

L2Shrinking
pipe orexpanding
pipe

4D

EMD7EMT1

EMTGP16D

4D
EMT1H

EMT612D

4D
EMP5A

EMRT1PL2）Gate valve,fully openP

L1

There must be a distanceof 5D or greater between
two bends.

19D

L1

L2

HWS15A

Accessories
Application

Precautions
Maintenance108

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 transactionwith 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 ofproduct 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 ordefect 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, contactGeneral
agent

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

Manufacturer

Yamamoto 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