POEM (Pressure Operated Electronic Meter) - The POEM is used for gauging flooded rivers or measuring flows from the spillways at hydroelectric schemes. The water velocity probe consists of a protected water turbo prop positive displacement sensor coupled to an expandable probe handle with a digital readout display. The above Table 1 shows the actual velocity speeds in the left column and the displayed speed at antenna to target angles in the right column if the radar gun is not adjusted for the horizontal angle from the position of the gun antenna to the target. There are several types of open channel flow meters, the traditional methods using primary devices such as flumes or weirs. Water flow instruments range from small acoustic doppler current profiling devices or small prop type meters for measuring very low flows in small streams, up to NIWA's flood-gauging POEM. The x and y-axis sensors generate a PWM signal internally to the accelerometer, The sensor is designed to provide a 50% duty cycle signal when it is sensing 0 g (where g is the unit of measurement of the earth's gravitational pull). Electromagnetic flow meter. Next, here are presented the Top 7 Liquid Flow Measuring Devices for Oil and Natural Gas. Instead, it must be calculated in a process known as stream gaging. point velocity probe (PVP) to investigate groundwater velocity below the water table suggested that the PVP may also be capable of measuring groundwater velocity within the capillary fringe. Copyright, NIWA. How do land use activities potentially influence water flows? “The device is a more efficient and inexpensive way to measure evaporation when compared with existing methods,” Bengaluru-based IISc said in a statement on Friday. Thus there has been provided a surface velocity radar gun with automatic cosine correction for measuring water velocity at an angle that fully satisfies the objects set forth above. water to back up, creating a head behind the barrier. 02062 under model number ADXL202. This Acoustic Doppler (water) Current Profiler (ADCP) can measure water velocity and discharge in shallow streams, ranging from 15 to 200 cm deep, in minutes. In all cases, the radar device is elevated above the water, so the vertical angle must be compensated for. The float rests on the water in a float well or a stilling well which is connected to the main channel by a pipe or a trench. Basically, the current meter is a wheel having several cups or vanes which turn round due to the force of water current. Such a device (Fig. This invention relates to measuring devices and more particularly to a surface velocity radar device for measuring water surface velocity. When the antenna transmits the beam of radio waves, the beam forms an elliptical pattern onto the target area. This is a two-axis accelerometer that is suitable for measuring static acceleration (e.g. The USGS has been doing this since 1889, when it established its first stream gage on the Rio Grande River in New Mexico to determine how much water was availabl… When the target's path (the water flow direction) is not parallel with the gun's antenna, the radar device displays a speed which is lower than the actual water surface velocity. 4.24) consists of a float suitably connected to a recording device. The fluctuations in the water level make the float move which in turn actuates a pen. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). The head is a function of flow velocity, and therefore, the flow rate through the device. Current meter measures the velocity of flowing water in an open channel or ditch and streams where direct methods of measurement are not practicable. These have been used to gauge rivers for decades, and despite being mechanical, are reasonably robust and reliable but, unlike the ADCP, need to be calibrated annually. DECATUR ELECTRONICS, INC., ILLINOIS, Free format text: Not all flow measuring devices ... wood, or fiberglass and can measure water over a wide variety of flow ranges. Velocity measurement of water flow is an important task in hydrological monitoring [1–3]. It is advantageous to be able to take the velocity measurements above the water surface so that waterproof instruments are not required. POEM is a Pressure Operated Electronic Meter, with no moving parts, developed for gauging flooded rivers with flow rates up to 10 m/sec. Magnetic flow meters, commonly referred to as "mag meters", are technically a velocity-type water meter, except that they use electromagnetic properties to determine the water flow velocity, rather than the mechanical means used by jet and turbine meters. ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SMITH, KIMBLE J.;JANSON, SCOTT D.;SMITH, KEVIN T.;REEL/FRAME:012183/0456;SIGNING DATES FROM 20010909 TO 20010911, Free format text: gravity). Read about how a POEM was used to gauge the flow of water entering the Lake Pukaki canal on the Waitaki hydroelectric scheme  POEM has no moving parts and, in addition to measuring flow up to 10m/s, can simultaneously provide useful information about turbulence. FIG. FIG. Streamflow cannot be measured directly, say, by plunging an instrument into a river. The true speed can be calculated from the indicated speed, using the following formula: If we assume the angle A is 10°, the cosine of A is 0.9848. A pitot tube is a simple device meant for measuring the velocity of a liquid at any point. primary radar systems; Analogous systems, Systems of measurement based on relative movement of target, Velocity or trajectory determination systems; Sense-of-movement determination systems, Velocity or trajectory determination systems; Sense-of-movement determination systems processing the video signal in order to evaluate or display the velocity value, ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SMITH, KIMBLE J.;JANSON, SCOTT D.;SMITH, KEVIN T.;REEL/FRAME:012183/0456;SIGNING DATES FROM 20010909 TO 20010911, ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION, Simulating a radar signal reflected from a moving target, Method and Apparatus for Acquiring Local Position and Overlaying Information, Radar speed measuring device and method based on angle compensation, Device for measuring the frequency of vibrations on a tight drive belt, and method for performing the vibration frequency measurement, Method for estimating flow by means of radar wave flow meter, The device measured for the frequency of vibration of driving belt being tensioned and for performing the method that frequency of vibration is measured, Device for measuring the frequency of vibration in a tensioned drive belt and method for performing vibration frequency measurement, Device for measuring the frequency of vibrations on a tight drive belt and a method for carrying out the vibration frequency measurement, Gyro sensor module and angular velocity detection method, Method and system for determining position and orientation of an object, Surveying and position measuring instrument with a fan-shapped light beam, Level, angle and distance measuring device, Monitor device that measures and displays the flight characteristics of sports objects, Yield monitoring apparatus, systems, and methods, Laser sensor capable of measuring distance, velocity, and acceleration, Low cost 2D position measurement system and method, Solid state orientation sensor with 360 degree measurement capability, System for determining performance characteristics of a golf swing, Handheld optical distance measurement device, Handheld laser light detector with height correction, using a GPS receiver to provide two-dimensional position data, System, method, device and computer code product for improving the readability of an electronic compass, Gradient sensor and method of using the same, Remote attitude and position indicating system, Method and apparatus to determine the wind speed and direction experienced by a wind turbine, Method of adjusting monitor axis of optical sensors, Golfer's wind indicator and club selection assistance device, Method and apparatus to determine object striking instrument movement conditions, System for using a 2-axis magnetic sensor for a 3-axis compass solution, Information on status: application discontinuation. There are also a few less commonly used devices, such as a radar setup that measures the velocity of waves and micro-waves on the surface of the water. Open channel flowmeters perform flow measurement of liquids that are open to the atmosphere at some point in the flow measurement path. There are many different types of meters by the most common is the Pygmy meter, the vortex meter, the flow probe, and the current meter: They are briefly described below. a processor mounted in the radar gun to receive the output signal. 1 there is illustrated a radar gun. Unlike the acoustic doppler devices and POEM, propellor current meters can't measure turbulence. When the beam strikes the target, a small amount of energy from the beam is reflected back to the antenna in the radar device. Many factors can generate currents, such as gravitational forces, rotation of the earth, wind, water conditions gradients and/or geographical landscapes. “The device is a more efficient and inexpensive way to measure evaporation when compared with existing methods,” Bengaluru-based IISc said in a statement on Friday. The outputs are duty cycle modulated (DCM) signals whose duty cycles (ratio of pulse-width to period) are proportional to the acceleration in each of the two axes (i.e. A sound velocity probe is a device that is used for measuring the speed of sound, specifically in the water column, for oceanographic and hydrographic research purposes. FIG. It is not the most practical way to measure the velocity, but that is not … When used in measuring the volume of water passing though the water in a water meter, or the speed of the water passing through a flow meter, it is actually measuring the sound as it bounces off of bubbles, dirt or impurities in the water. Electromagnetic meters. If the indicated speed on the radar gun is 10 feet per second and no cosine correction is made, then the actual speed of the water is 11.17 feet per second. When taking readings of moving water, such as rivers or streams, the radar gun is generally positioned above the stream, on a bridge, or adjacent to the stream, on a riverbank. a tilt sensor mounted in the radar gun to provide an output signal that includes a tilt angle component. We offer the Global Water Flow Probe. It is primarily used in measuring discharge. These large propeller type meters are supplied with one propeller for flows up to 6.0 m/s. This small bucket wheel current meter has a very low starting velocity and no tail fin, so is ideal for measuring very low flows in shallow water. Propellor current meters - these are the older mechanical meters and still the standard in New Zealand. Buy Gowe Water Velocity Apparatus, Velocity Flow Measuring Devices, Hydrological Instruments: Digital Calipers - Amazon.com FREE DELIVERY possible on eligible purchases At the same time that the microprocessor is receiving a reading from the y-axis sensor, Turning to FIG. This internal automatic compensation allows for accurate measurement of the surface velocity of the water. The Pitot tube was invented by a french engineer Henri Pitot i early 18s and further modified by a french scientist Henry Darcy. A radar gun transmits and directs a signal or beam of microwave energy (radio waves) having a given frequency at an approaching or receding target. By placing the accelerometer in the radar gun. The radar gun reads the frequency data from the tilt sensors, and the computer software uses this in calculating the cosine corrected angle of the angle formed by the radar device and the point where the velocity is measured. All rights reservedPrivacy Policy, 2016, Free phone within New Zealand: 0800 RING NIWA (0800 746 464) Contact details, Air quality monitoring with low-cost sensors, ICES Expert Working Group Meetings – April 2017, Neon Remote Terminal (NRT Terrestrial) - Unidata, Small prop current meters - Ott, Oss, Seba, CHES - smarter use of New Zealand's river waters, NIWA research vessel returns home after epic voyage, Fresh scientific scrutiny for Arrowtown air, Shining new light on ground water measurements, Meeting the flood challenge in post-quake Christchurch. The electromagnetic flowmeter is capable of measuring flow rates in different water quality conditions, which brings small disturbances to the water flow, and can measure instantaneous flow rates, but the method is susceptible to interference from nearby electromagnetic … It is an object of the invention to provide a radar gun that measures surface velocity and automatically compensates for the vertical or tilt angle of the gun with respect to the target. means for correcting the velocity measured to correct for the radar gun being disposed above or below the horizontal thus resulting in an erroneous reading due to the radar gun being disposed at an angle with respect to the horizontal, the means for correcting the velocity measured being a sensor that senses the angle of the radar gun with respect to the horizontal. Mobile measuring system for non-contact discharge measurement. 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