speed measuring instruments

Research No.3Date Submitted: 7-23-15Research Title: Speed Measuring Instruments

Objectives:

1.) To know and discuss various speed measuring instruments and their specific application in the industry.2.) To discuss proper usage and maintenance of various speed measuring instruments

Instrument No.1 Tachometer

DescriptionTachometer (Mechanical)DescriptionA tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine.[1] The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common. The word comes from Greek (tachos "speed") and metron ("measure")

Tachometers (Figure 2-13) are measuring instruments that give a direct and continuous indication of rotary speed in rpm. For submarine diesel engines, the mechanical tachometers are usually permanently mounted on a gage board. They are generally driven from the engine camshaft through a gearing and a flexible shaft. In operation, the force produced by the rotation is balanced against a calibrated spring or against the force of gravity. Those used in submarines are usually of the indicator type in which the pointer registers the rpm at the moment, rising and falling with the fluctuations in engine speed..

History The first mechanical tachometers were based on measuring the centrifugal force, similar to the operation of a centrifugal governor. The inventor is assumed to be the German engineer Dietrich Uhlhorn; he used it for measuring the speed of machines in 1817.[citation needed] Since 1840, it has been used to measure the speed of locomotives.

Components and Parts

Indicator displays rotational speed exerted from the engine camshaft through the flexible shaft assemblyFlexible Shaft transfers the kinetic energy exerted of the engine shaft to the mechanical indicatorEngine Camshaft serves as kinetic energy source

Industrial ApplicationsTachometers or revolution counters on cars, aircraft, and other vehicles show the rateofrotation of the engine's crankshaft.In vehicles such as tractors and trucks, the tachometer often has other markings,usually agreen arc showing the speed range in which the engine producesmaximum torque, which isof prime interest to operators of such vehicles.Aircraft tachometers have a green arc showing the engine's designed cruising speedrange.Tachometers are used to estimate traffic speed and volume (flow). A vehicle isequipped withthe sensor and conducts "tach runs" which record the traffic data.In analogue audio recording, a tachometer is a device that measures the speed ofaudiotape as it passes across the head. On most audio tape recorders the tachometer (or simply "tach") is a relatively large spindle near the ERP head stack, isolated from the feed and take-up spindles by tension idlers.On many recorders the tachometer spindle is connected by an axle to a rotatingmagnet that induces a changing magnetic field upon a Hall effect transistor. Othersystems connect the spindle to a stroboscope, which alternates light and dark upon aphotodiode.

Usage Instructions

Majority of mechanical tachometers operate in the same principles which are following;Principle 1: A Kinetic energy source in the form of rotational displacements such as engine camshafts serves as the registrants of dataPrinciple 2: a gear assembly used to transmit the power from the energy source to the dialPrinciple 3: An indicator assembly (dial) registers the actual power obtained from the source through the gear assembly and displays the registered data (power) due to the mechanical work performed by the indicator assembly pushing the dial to move at a scale.

Maintenance and StorageFor Mechanical Tachometers

Maintenance1.) Proper calibration must be in place2.) Fasteners properly fastened.3.) Periodic checking for the presence of destructive and constructive mechanical and chemical corrosions.4.) Internal mechanical parts must be periodically properly lubricated.

Storage:1.) Must not be exposed to direct sunlight unnecessarily.2.) Must be stored in the prescribed humid environment.3.) Must be stored in the prescribed vibrational environment.

Referencehttps://en.wikipedia.org/wiki/TachometerErjavec, Jack (2005). Automotive Technology. ISBN 1-4018-4831-1.http://maritime.org/doc/fleetsub/diesel/chap2.htm

Instrument No.2 Speedometer

Figure 2.1 Construction of a SpeedometerDescriptionA Speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the 1900s, and as standard equipment from about 1910 onwards.[1] Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an airspeed indicator.Charles Babbage is credited with creating an early type of a speedometer, which were usually fitted to locomotives.[2][3]The electric speedometer was invented by the Croatian Josip Belui[4] in 1888, and was originally called a velocimeter.

Typical speedometers are readily integrated in the system (land and air vehicles)

Components and PartsSee figure 2.1

Industrial ApplicationsIn Land-craft and Aircraft Machineries -> used to measure actual speed transferred (done on the medium of actuation like engine camshaft etc.)

Maintenance and StorageFor Speedometers

Maintenance1.) Proper calibration must be in place 2.) Fasteners properly fastened.3.) Periodic checking for the presence of destructive and constructive mechanical and chemical corrosions.4.) Internal mechanical and electrical parts (since it is an mechanically and electrically integrated system) must be periodically for proper lubrication if necessary

Storage:1.) Must not be exposed to direct sunlight unnecessarily. 2.) Must be stored in the prescribed humid environment. 3.) Must be stored in the prescribed vibrational environment.

Reference:Harris, William (10 July 2007). "How Speedometers Work". How stuff works. Retrieved 30 January 2015."Charles Babbage and the Difference Engine - NewMyths.com". google.com. Retrieved 30 January 2015."Udini Flow". proquest.com. Retrieved 30 January 2015.

Instrument No.3

Disdrometer

DescriptionA disdrometer is an instrument used to measure the drop size distribution and velocity of falling hydrometeors. Some disdrometers can distinguish between rain, graupel, and hail.

The uses for disdrometers are numerous. They can be used for traffic control, scientific examination, airport observation systems, and hydrology. The latest disdrometers employ microwave or laser technologies. 2D video disdrometers can be used to analyze individual snowflakes.


Due to unconventional constraints regarding the gatheringof necessary data to fill-in the Component and Parts & Usage Instructions, Usage Instructions, & Maintenance and Storage Sections of disdrometers, the author is unable to provide such information. That the author primarily believes the factors of constraints are far more likely derived from propertartial rights and information security

Industrial Applications

In the Fields of:Meteorological Research, Weather Forecasting, Agricultural Research, Traffic control, Airport observation systems, & Hydrology. Reference:https://www.arm.gov/instruments/disdrometerhttps://en.wikipedia.org/wiki/Disdrometer

Further Research Recommendation:

Additional supporting publications about distrometer usage and calibration manuals are released by the US Department of Energy ARM Research Facility (2009)

https://www.arm.gov/publications/tech_reports/handbooks/disdrometer_handbook.pdf

Illustration 3:Distrometer RD-80by US Department of Energy ARM

Instrument No.4 and 5

Anemometers

DescriptionAn anemometer is a device used for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed measurement instrument used in meteorology. The first known description of an anemometer given by Leon Battista Alberti in 1450.

Figure 4.1 Modern Anemometer (WAA151 Anemometer)The anemometer has changed little since its development in the 15th century. Leon Battista Alberti is said to have invented the first mechanical anemometer around 1450. In following centuries, numerous others, including Robert Hooke and the Mayans, developed their own versions, with some being mistakenly credited as the inventor. In 1846, John Thomas Romney Robinson improved upon the design by using four hemispherical cups and mechanical wheels. Later, in 1926, John Patterson developed a three cup anemometer, which was improved by Brevoort and Joiner in 1935. In 1991, Derek Weston added the ability to detect wind direction. Most recently, in 1994, Dr. Andrews Pflitsch developed the sonic anemometer.

Two of the Different Types of Velocity Anemometers by Differentiated by Mechanical Configuration

Instrument No. 4: Cup anemometersA simple type of anemometer was invented in 1845 by Dr. John Thomas Romney Robinson, of Armagh Observatory. It consisted of four hemispherical cups, each mounted on one end of four horizontal arms, which in turn were mounted at equal angles to each other on a vertical shaft. The air flow past the cups in any horizontal direction turned the shaft in a manner that was proportional to the wind speed. Therefore, counting the turns of the shaft over a set time period produced the average wind speed for a wide range of speeds. On an anemometer with four cups, it is easy to see that since the cups are arranged symmetrically on the end of the arms, the wind always has the hollow of one cup presented to it and is blowing on the back of the cup on the opposite end of the cross.


See figure 4.1

ApplicationsMeteorological Research, Weather Forecasting, Agricultural Research

Usage Instructions

Maintenance and Storage

Maintenance1.) Proper calibration must be in place2.) Fasteners properly fastened.3.) Periodic checking for the presence of destructive and constructive mechanical and chemical corrosions.4.) Internal mechanical parts must be properly checked for lubrication periodically.


Instrument No. 5: Vane Anemometers

One of the other forms of mechanical velocity anemometer is the vane anemometer. It may be described as a windmill or a propeller anemometer. Contrary to the Robinson anemometer, where the axis of rotation is vertical, the axis on the vane anemometer must be parallel to the direction of the wind and therefore horizontal. Furthermore, since the wind varies in direction and the axis has to follow its changes, a wind vane or some other contrivance to fulfill the same purpose must be employed.

An vane anemometer thus combines a propeller and a tail on the same axis to obtain accurate and precise wind speed and direction measurements from the same instrument. The speed of the fan is measured by a rev counter and converted to a wind speed by an electronic chip. Hence, volumetric flow rate may be calculated if the cross-sectional area is known.In cases where the direction of the air motion is always the same, as in the ventilating shafts of mines and buildings for instance, wind vanes, known as air meters are employed, and give most satisfactory results.


ApplicationsMeteorological Research, Weather Forecasting, Agricultural ResearchVentilation Shafts in Mining Operations, Ventilation Shafts in Commercial and Industrial Infrastructures

Usage InstructionsMajority of mechanical tachometers operate in the same principles which are following;Principle 1: A Kinetic energy source in the form of gaseous flow such as ventilation chambers etc, as the registrants of dataPrinciple 2: Vane Anemometers are used to register the direction of flow of the gasThus usage instructions for vane anemometers such as physical construction and installation of various mechanical vane anemometer will adhere (not violate) the principles as indicated above.

Consequently more complex vane anemometers currently exist in the industry further giving more complex working principles and installation instructions.

Disclaimer: The Instrument No. 5: Vane Anemometers section will not display such complex vane anemometers but exhibit simple vane anemometer construction and working principle only.

Maintenance and Storage

Maintenance1.) Proper calibration must be in place2.) Fasteners properly fastened.3.) Periodic checking for the presence of destructive and constructive mechanical and chemical corrosions.4.) Internal mechanical parts must be properly checked for lubrication periodically.


Reference for Instruments 4 and 5"History of the Anemometer". Logic Energy. Retrieved 14 April 2013. World Meteorological Organization. "Vane anemometer". Eumetcal. Retrieved April 6, 2014.http://www.vaisala.com/Vaisala%20Documents/User%20Guides%20and%20Quick%20Ref%20Guides/WAA151_User_Guide_in_English.pdf

Submitted To: Engr. Adrian C. Flores, RME. MMERegistered Mechanical EngineerMaster of Mechanical EngineeringMechanical Engineering DepartmentBulacan State University College of Engineering

Submitted By: Joseph Joshua C. GarciaMechanical Engineering StudentME 4AClass 2012-2017