Mass Flow Sensor
Automotive mass airflow sensors
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A mass airflow sensor.
A mass air flow sensor is used to find out the mass of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient temperature, altitude and use of a turbocharger and this is an ideal application for a mass sensor. (See stoichiometry and ideal gas law.)
There are two common types of mass airflow sensors in usage on automotive engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine’s air mass flow rate can be accurately determined.
Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0.0- 5.0 volt or a pulse-width modulation (PWM) signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.
When a MAF is used in conjunction with an oxygen sensor, the engine’s air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass. Also see MAP sensor.
Vane meter sensor
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A vane, or paddle, projects into the engine intake air stream on a spring-loaded arm. The vane moves in proportion to the airflow, and a voltage is generated in proportion to the distance the vane moves, or the movement of the vane directly regulates the amount of fuel injected, as in the K-Jetronic system.
The vane moves because of the drag force of the air flow against it, it does not measure volume or mass directly. The drag force depends on air density, velocity and the shape of the vane, see drag equation.
The vane meter approach has some drawbacks:
it restricts airflow which limits engine output
its moving electrical or mechanical contacts can wear
finding a suitable mounting location within a confined engine compartment is problematic
the vane has to be oriented with respect to gravity.
Hot wire sensor (MAF)
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A hot wire mass airflow sensor determines the mass of air flowing into the engine air intake system. The theory of operation of the hot wire mass airflow sensor is similar to that of the hot wire anemometer (which determines air velocity). The General Motors division (GM) was the first car company to use the hot wire sensor.[citation needed] This is achieved by heating a wire with an electric current that is suspended in the engine air stream, like a toaster wire. The wire’s electrical resistance increases as the wire temperature increases, which limits electrical current flowing through the circuit. When air flows past the wire, the wire cools, decreasing its resistance, which in turn allows more current to flow through the circuit. As more current flows, the wire temperature increases until the resistance reaches equilibrium again. The amount of current required to maintain the wire temperature is directly proportional to the mass of air flowing past the wire. The integrated electronic circuit converts the measurement of current into a voltage signal which is sent to the ECU.
If air density increases due to pressure increase or temperature drop, but the air volume remains constant, the denser air will remove more heat from the wire indicating a higher mass airflow. Unlike the vane meter’s paddle sensing element, the hot wire responds directly to air density. This sensor’s capabilities are well suited to support the gasoline combustion process which fundamentally responds to air mass, not air volume. (See stoichiometry.)
Some of the benefits of a hot-wire MAF compared to the older style vane meter are:
responds very quickly to changes in air flow
low airflow restriction
smaller overall package
less sensitive to mounting location and orientation
no moving parts improve its durability
less expensive
separate temperature and pressure sensors are not required (to determine air mass)
There are some drawbacks:
dirt and oil can contaminate the hot-wire deteriorating its accuracy
installation requires a laminar flow across the hot-wire
“Coldwire” sensor
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The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page.
A Holden Commodore’s MAF sensor
The GM LS engine series (as well as others) use a “coldwire” MAF system (produced by AC Delco) where the inductance of a tiny sensor changes with the air mass flow over that sensor. The sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance; hence the frequency is related to the amount of air (cubic feet per minute) passing over the unit. This oscillating electrical signal is then fed to the car’s ECU. These MAF units (such as the one pictured) have 3 pins, denoted +, – and F. F carries the square-wave frequency between – and F. They are powered by +5 VDC from the ECU’s regulated power supply.
The mesh on the MAF is used to smooth out airflow to ensure the sensors have the best chance of a steady reading. It is not used for measuring the air flow per se. In situations where owners use oiled-gauze air filters, it is possible for excess oil to coat the MAF sensor and skew its readings. Indeed, General Motors has issued a Technical Service Bulletin, indicating problems from rough idle all the way to possible transmission damage resulting from the contaminated sensors. To clean the delicate MAF sensor components, a specific MAF or Electronics Cleaner should be used, not carburetor or brake cleaner. These are alcohol or CFC-based solvents, rather than the harsh petroleum distillates used in the other cleaners… The sensors should be gently sprayed from a careful distance to avoid physically damaging them. Manufacturers claim that a simple but extremely reliable test to ensure correct functionality is to tap the unit with the back of a screwdriver while the car is running, and if this causes any changes in the output frequency then the unit should be discarded and an OEM replacement installed.
Krmn vortex sensor
Animation of the phenomenon. Courtesy, Cesareo de La Rosa Siqueira.
A Krmn vortex sensor works by setting up a laminar air stream. The air stream is disrupted by a vertical bow in the sensor. This causes a wake in the air stream and subsequently the wake will collapse repeatedly and cause Krmn vortexes. The frequency of the resulting air pressure oscillation is proportional to the air velocity.
These vortexes can either be read directly as a pressure pulse against a sensor, or they can be made to collide with a mirror which will then interrupt or transmit a reflected light beam to generate the pulses in response to the vortexes. The first type can only be used in pull thru air (prior to a turbo- or supercharger), while the second type could theoretically be used push or pull thru air (before or after a forced induction application like the previously mentioned super- or turbocharger). Instead of outputting a constant voltage modified by a resistance factor, this type of MAF outputs a frequency which must then be interpreted by the ECU. This type of MAF can be found on Mitsubishi Lancers/EVOs, all DSMs (Mitsubishi Eclipse, Eagle Talon, Plymouth Laser) and some Toyota’s and Lexuses.
More information can be found here:
Membrane sensor
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An emerging technology utilizes a very thin electronic membrane placed in the air stream. The membrane has a thin film temperature sensor printed on the upstream side, and one on the downstream side. A heater is integrated in the center of the membrane which maintains a constant temperature similar to the hot-wire approach. Without any airflow, the temperature profile across the membrane is uniform. When air flows across the membrane, the upstream side cools differently from the downstream side. The difference between the upstream and downstream temperature indicates the mass airflow. The thermal membrane sensor is also capable of measuring flow in both directions, which sometimes occur in pulsating situations. Technological progress allows this kind of sensor to be manufactured on the microscopic scale as microsensors using Microelectromechanical systems technology. Such a microsensor reaches a significantly higher speed and sensitivity compared with macroscopic approaches. See also MEMS sensor generations.
Auto Repair Technician observation
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The Mass Air Flow (MAF) sensor senses the amount of incoming air (Volume) into the engine. This sensor does not regulate the incoming air, this is done by the engine throttle plates. The MAF merely senses incoming air and relates a signal to the ECM. Air flow sensors come in three types. The Vane Air Flow sensor, Hot Wire MAF sensor and Hot Film MAF sensor. They all perform the same function but their operation is quite different.
The VAF sensor measures the amount of air flow into the engine with a spring-loaded air flap/door attached to a variable resistor (potentiometer). VAF sensors measure air volume and not mass. The incoming air strikes or pushes against the internal air flap on the VAF sensor, which also moves the variable resistor sensing arm (wiper arm). As air flows into the engine the mechanical air flap rotates further, causing the wiper arm to contact a series of resistors, changing the voltage signal output.
The VAF sensor has an air-fuel adjustment screw, which opens or closes a small air passage on the side of the VAF sensor. This screw controls the air-fuel mixture by letting a metered amount of air flow past the air flap, thereby, leaning or richening the mixture. By turning the screw clockwise the mixture is enriched and counterclockwise the mixture is leaned. In addition to the regular air flow measuring function, some VAF sensors also employ an air temperature sensor (IAT sensor) and a fuel pump switch.
The IAT sensor is found inside the VAF casing and has the same electrical characteristics as a regular air temperature sensor. The VAF sensor flap also closes a set of contacts that activate the fuel pump relay coil (circuit opening relay). The contacts are actually closed as soon as the smallest amount of air pushes on the air flow flap. Once this happens the fuel pump starts running and the engine starts.
One of the main drawbacks of the VAF sensor is that it measures volume of air and not weight. As air temperature changes so does its weight. There are more air molecules present when the air is colder than when it is hotter. As air temperature decreases, more air is absorbed by the engine, so there are drastic changes needed in the air fuel ratio (depending on the temperature of the air). The air temperature sensor inside the VAF somewhat compensates by signaling the ECM of any changes in air temperature.
The HOT WIRE MAF sensor is a fully electronic unit. It senses the amount of air flow into the engine by measuring the amount of current needed to maintain a constant temperature through a very thin (70 micrometers) platinum hot wire. Hence the name hot wire MAF sensor. It also measures air by weight, since it takes into consideration the air temperature as well.
This sensor works as follows. As the air enters the intake manifold through the hot wire MAF sensor it cools down the platinum wire, which is heated at a very precise temperature. When the MAF circuitry senses the platinum wire cooling down it increases the amount of current flow through the hot wire trying to maintain a specific temperature. This varying current flow is then converted to a voltage output signal by the MAF electronic circuitry and is used as an air flow indicator by the ECM. Hot wire MAF sensors have a signal that is directly proportional to air flow. So as air flow increases so does its voltage signal output.
This sensor sometimes employs a mixture screw, but this screw is fully electronic and uses a variable resistor (potentiometer) instead of an air bypass screw. The screw needs more turns to achieve the desired results. A hot wire burn-off cleaning circuit is employed on some of these sensors. A burn-off relay applies a high current through the platinum hot wire after the vehicle is turned off for a second or so, thereby burning or vaporizing any contaminants that have stuck to the platinum hot wire element.
The HOT FILM MAF sensor works somewhat similar to the hot wire MAF sensor, but instead it usually outputs a frequency signal. This sensor uses a hot film-grid instead of a hot wire. It is commonly found in late 80 early 90 fuel injected vehicles. The output frequency is directly proportional to the amount of air entering the engine. So as air flow increases so does frequency. These sensors tend to cause intermittent problems due to internal electrical failures. The use of an oscilloscope is strongly recommended to check the output frequency of these sensors. Frequency distortion is also common when the sensor starts to fail. Many technicians in the field use a tap test with very conclusive results. Not all HFM systems output a frequency. In some cases, this sensor works by outputting a regular varying voltage signal.
Conditions that affect operation
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VAF sensors are mechanical in nature. Their measuring element (wiper contact, pivot bushings and sensor resistors) get worn out over time. A binding air flap door is also a major problem with these sensors. The air flap mechanism is extremely precise and does not tolerate any misalignments. Always make sure that the air flap can travel freely all the way to its full open position. A broken air duct pipe will also render the VAF useless, since most of the air will be bypassed and enter though the broken duct hole. A thorough air duct check is always a good idea. The resistors also tend to wear out over time, sending the wrong voltage signal to the ECM. This will certainly throw off the air-fuel ratio.
The air temperature sensor and the fuel pump switch are the other reasons for VAF failures. This fuel pump switch activates the fuel pump relay and its contacts also wear down over time, causing a no start-no no-fuel pressure condition. A simple continuity test will quickly reveal a bad fuel pump switch. The air temperature sensor also follows the same electrical characteristics of a normal IAT sensor and the same ohms to temperature tables could be used for diagnostics.
Hot Wire MAF sensors are very prone to sensing wire element contamination. A condition referred to by many technicians as rowing hairs happens when debris, dirt from cheap air filters and outside air stick to the sensing wire element, shielding it from the incoming air. This shielding effect prevents the MAF sensor from correctly measuring the air flow and mass causing severe air-fuel ratio control problems. An ECM not in control while at pre-load is a strong indication of a dirty MAF.
In any fully electronic device, the electrical connections and circuitry fails after a certain lifespan of operation. An output signal voltage test will surely reveal a bad MAF sensor.
Hot Film MAF sensors tend to get electrical damage more often that the other type of sensors. The tap test ,as mentioned before, is a useful and simple procedure that usually reveals a bad hot film MAF sensor. Contamination or a broken air duct is also a problem for this type of sensor.
Manufacturers
Automotive air measurement sensors are manufactured by several manufacturers, including Continental VDO, Sensata Technologies, Bosch, Denso, Visteon, Delphi, AC Delco, Hitachi, Pierburg, Lwe Automobil, and Gill Sensors. The biggest manufacturers are Bosch, Siemens VDO and Pierburg.
Laminar flow elements
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Laminar flow elements measure the mass flow of gases directly. They operate on the principle that, given laminar flow, the pressure difference across a pipe is linear to the flow rate. Laminar flow conditions are present in a gas when the Reynolds number of the gas is below the critical figure. The viscosity of the fluid must be compensated for in the result. Laminar flow elements are usual constructed form a large number of parallel pipes to achieve the required flow rating.
See also
List of sensors
Manifold absolute pressure (MAP)
References
^ “Air Flow Sensors”. http://www.autoshop
Managing The Reverse Flow: Speeding Recalls And Returns With Radio Frequency Identification
Synopsis
Why are big retailers like Wal-Mart, Best Buy, and Target in the United States and Metro and Tesco in Europe so excited about RFID (Radio Frequency Identification)? Why is the US Defense Department mandating that RFID be used throughout its global supply network? Why are major pharmaceutical manufacturers (like Pfizer, Purdue Pharma, and GlaxoSmithKline) and drug wholesalers (including AmerisourceBergen, Cardinal Health and HD Smith) embracing RFID for its track-and-trace capabilities? In short, it is because of the visibility that RFID gives to organizations – visibility that is needed and expected in today’s increasingly fast-paced, interconnected and competitive world.
Overview
From a strategic perspective, we increasingly live in what could be termed a “Google Earth” world. To draw upon this analogy, just think how much our lives have been transformed by the power of information. A decade or so ago, if we were looking for a specific address in an unfamiliar area, how would we find it? Well, it would most certainly be done in a low-tech manner, by asking for directions or stopping at a gas station or a convenience store to ask for help.
Five years ago, we began to use MapQuest and – to a lesser extent – other web-based navigation tools. This made it possible to leave our homes with a print-out that had complete, turn-by-turn directions from any point A to any point B. We then began to see in-car navigation systems like OnStar come of age, providing us graphical directions and even voice prompts telling us what road to take and where to exit, turn, and stop. Today, we can sit at our desktop or view a laptop propped on the passenger seat to use Google Earth and view incredibly detailed photos from the sky of exactly what we will see on the ground, enabling us to zoom in on the exact parking space of the building at the address we are heading to. Thus, for anywhere we could physically wish to go on the planet – from Boise to Baghdad – we can now expect to have incredible visibility and real-time information. We expect – and demand – to be able to instantly find the proverbial “needle in the haystack” anywhere, anytime.
RFID and the Retail Supply Chain
The same is becoming true – and necessary – in today’s retail supply chains. With the global supply chains necessary to stock Target’s store shelves in Wichita Falls or Walgreen’s in Memphis stretching back to Hong Kong, Managua and other far-flung locales, major retailers must seek to have global business intelligence systems in place, managing movements of goods from manufacturer through shipment to their distribution center, to the stock room, to the store shelf through checkout. But barcodes present a crucial limitation: whereas they can only identify a class of items – a type of box of cereal for example – RFID can uniquely identify the specific box of that cereal that you are holding at the moment or the dozen on the store shelf in front of you. The promise of RFID in retail is to provide ROI through increased sales, increased inventory availability, reduced stock-outs and labor cost savings and the ultimate “retail nirvana” – still probably a decade or so away – where every item is tagged with RFID and “smart stores” promise interactive shelves and “roll through” checkouts. All this is made possible through the increased visibility that RFID brings and the imagination to use this data to better manage retail operations.
Take a simple example – in-store promotions. Let’s say that for the Super Bowl, a major retailer and a major snack food supplier are cooperating on a promotion for tortilla chips and salsa. For the big game, the supplier had stocked the products in four different locations in the store – the snack food aisle, the middle of a major traffic aisle, a special display set-up on the adult beverage aisle, and point-of-purchase displays in the checkout aisles. In today’s present environment, with bags of chips and jars of hot sauce being identified through barcodes, while it would be possible to gauge the overall effectiveness of the campaign (i.e., sales were up X% over last year at the same time and Y% over a “normal” weekend), it would be impossible to really assess the true, operational-level results of the Super Bowl promotion.
Fast forward to the near future when the products are RFID tagged and uniquely identifiable, and the retailer and snack food company could dig into far deeper and richer sets of data to ascertain – with great precision – the campaign’s effectiveness. For instance, both parties could discover previously undiscoverable consumer behavior insights such as from which display the items were purchased, which combinations of items were bought (sizes, flavors, etc.), which promotional items were bought with other non-promotional items, and so on. Thus, from this simple example one can only imagine how the increased visibility can be used by retailers (and their supply chain and logistics partners) to create new ways of managing the entire extended enterprise.
RFID and Reverse Logistics
For all the excitement about the advantages that RFID will bring to the forward retail supply chain, the really untold story regards the benefits that the technology will bring to the reverse supply chain. How so? Let’s start at the store level. With each item individually identifiable, the reverse logistics operation can begin with far greater intelligence. Shelves and stock rooms can be scanned to locate expired items that should be discarded and unsold stock that should be returned to the manufacturer for credit and/or shipped to a reseller. Likewise, when an item is returned by a customer, the retailer can track the specific purchase history of the item (where, when, how it was bought). Thus, retailers should be able to immediately spot a fraudulent return, and in time, eliminate that problem, which costs retailers billions annually. In the same way, when an item is returned for warranty work, the specific history of that item can be compiled. For both the retailer and the manufacturer, this will add an “early warning system” for problem items with high return and defect rates, enabling them to pinpoint such concerns far more effectively and quickly than today’s return data.
Perhaps the most important reverse logistics benefit will be in the area of recalls. Today, when products are recalled, it’s a matter of recalling way, way more than necessary – just to be safe. The quintessential example of this is the 2000 recall of Bridgestone/Firestone SUV tires, which involved the recall and replacement of over 6 million tires on Ford Explorers and other like models. If RFID tagging had been in place, rather than the mass recall – and mass hysteria that resulted from it – Bridgestone/Firestone could have been much more precise in its recall and replacement effort, since the problem was deduced to be specific production runs on specific days at its plant in Decatur, Illinois. This would have enabled the company to replace perhaps thousands of tires rather than millions, saving it and Ford immeasurable losses in the marketplace from their damaged brands and reputations. The recall could have been made even more effective by focusing more on the South and West, where warmer temperatures were correlated to higher failure rates for the problem tires.
Recalls in the Pharmaceutical Sector
While product recalls are a concern across all consumer-facing industries, there can be no greater area of emphasis than in the pharmaceutical sector, where product recalls can be a matter of life and death. Indeed, drug recalls are becoming increasingly common. According to the most recent data from the US Food and Drug Administration’s Center for Drug Evaluation and Research, the number of recalls involving both prescription and non-prescription pharmaceuticals has doubled over the past decade.
The most infamous drug recall case was the Tylenol case of twenty-five years ago. In reaction to the news that consumers had died as a result of product tampering, Johnson & Johnson executives made the decision to recall all Tylenol products. In the long-run, the brand survived and thrived, but in the short-term, the recall had a devastating effect. In fact, Tylenol’s market share in pain relievers at the end of 1982 had fallen to 8%, down from well over a third of the market a year earlier.
Drug recalls are costly endeavors, as they involve much administrative and logistical effort to make sure that all suspect product is taken off store and stockroom shelves and out of distribution channels. They also take a marketing toll on the brand and the company, as unlike with Tylenol, some brands are taken off the market forever or never recover their former standing. In fact, a recent University of Wisconsin study estimates that while the demonstrable cost of the typical drug recall runs into the millions, the decline in shareholder value following a drug recall is twelve times that of the total expenses incurred by firms in conducting the recall, replacing the product, and handling litigation associated with the recall.
An e-Pedigree Standard
EPCGlobal announced earlier this year the development of a broad e-pedigree standard that will work not just for the drug industry, but across many product lines. Having an e-pedigree available will enable drug recalls to be targeted with far greater precision as opposed to the former, “clear the shelves” methods that had to be utilized. For example, in a recent recall of the injectable drug methotrexate, used in the treatment of certain types of cancers and psoriasis, US Oncology was able to use pedigree data to target the recall to only those practices that had received a specific lot, making the process quick and effective.
Thus, in the future, when recalls happen, whether it be for pharmaceuticals (as with the recent Perrigo recall of store-branded acetaminophen) or suspect food items, the recalls can be accomplished with far more precision and speed than in the past, thanks to RFID tagging. Retailers can quickly separate cartons and individual units of recalled items from their retail shelves, stockrooms, and distribution centers, eliminating the need for hand searching for the suspect lots of goods. Manufacturers can also be more certain as to the overall completeness and effectiveness of their recall efforts, with new metrics and abilities to analyze the incoming items.
Finally, aside from drug recalls that occur from a specific safety or public health concern, the pharmaceutical companies must absorb costs estimated at exceeding billion annually from the return of outdated and overstocked products. Both at the store and wholesale level, there would be far greater ability to better manage inventory. Lucy Deus, vice president of Product Development for SupplyScape, recently commented that for all parties in the pharmaceutical supply chain, the direct visibility they will have will enable them to better manage shelf life and expiration dates. Also, in regards to managing expiration dates, analysts have projected that if RFID labeling is combined with sensor technology, products could have rolling expiration dates, which could give updated estimates on product usability. For instance, if a drug shipment endures extreme heat conditions during transit, or if a power outage during a blizzard causes products on the shelf to be exposed to harsh cold, the expiration date on the drug bottle or vial could be shortened according to pre-determined algorithms based on research. They could even be instructed to immediately expire if the conditions exceeded certain thresholds.
Analysis
As we consider the ROI of RFID, many times vendors and solutions providers miss the mark in terms of being able to portray what the RFID-enabled future will look like. We worry too much about the small stuff of today’s issues – read rates, tag prices, tag reliability and availability, etc. However, while these mechanical and operational issues indeed need to be worked out quickly, as we look not so far down the road, there is a bright future ahead with incredible, unanticipated returns on the investment in RFID technology from every perspective along consumer-facing supply chains – much of it to be gained in the reverse flow of products. It will be up to those in the auto ID industry to make the case that in the “Google Earth” world, RFID is the right technology to provide the real-time visibility that is vital to effective product management in today’s global economy, enabling retailers, distributors and wholesalers to find the unsold, suspect, outdated, or recalled needle in the haystack in a quick, efficient, and cost-effective manner. Such is managing in the new, new economy, being made possible with RFID.
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David C. Wyld (dwyld@selu.edu) is the Robert Maurin Professor of Management at Southeastern Louisiana University in Hammond, Louisiana. He is a management consultant, researcher/writer, and executive educator. His blog, Wyld About Business, can be viewed at http://wyld-business.blogspot.com/.
Posted in Gas Flowing | 
Flow, Frequency, Identification, Managing, Radio, Recalls, Returns, Reverse, Speeding | 
Leave a commentThe Ultrasonic Gas Flow Meter
While it seems like a simple question, an ultrasonic gas flow meter is a very complicated piece of equipment. These devices are used to measure the flow of gases and fluids through a pipe. While some are fixed, they also come in an ultrasonic flow meter portable version. These units are great for getting a quick reading and are almost as accurate as the fixed version.
Features and Functions of a Ultrasonic Gas Flow Meter
The units are generally non intrusive so that they will not affect the flow running through the pipe being measured. There are several different methods for measuring flow from transit time correlation to concurrent transit time, pulsed Doppler and continuous wave Doppler.
Not all applications are the same and it is important to be able to offer flow meters that suit the actual requirements. The use of non intrusive measuring devices has increased in popularity over the last ten years saving valuable time and in addition preventing the contamination of surrounding areas.
The ultrasonic gas flow meter is incredibly sensitive piece of equipment and a good one will be able to tell within a very fine area how much gas is flowing.
These clamp on ultrasonic gas flow meters can measure the erosive, corrosive, toxic, high purity sterile gases or any application where penetrating the pipe wall is undesirable. Theses meters generally will have a wide range and the meters will have no wetted or moving parts for virtually no maintenance. A clamp on ultrasonic gas flow meter will not cause any drop in pressure, as it resides outside the pipe.
For the most part meters will also offer the option to export there readings directly to a computer.
This can be done through any number of auxiliary inputs and is useful to monitor and compare data from multiple ultrasonic gas flow meters.
As you can see a gas flow meter is much more complicated than it would first appear. They come in a variety of forms and can be used in a variety of applications. It is up to you the user to decide what the best application for your ultrasonic gas flow meter is, and which one will best fit.
Whether it is a fixed or portable unit, whether it measures multiple values simultaneously or simply does individual ones is up to you. The important thing is that these devices no longer need to be placed inside the pipe and you can safely and reliable measure the flow with no harm to the outlying areas.
Running for the first time after rebuild. Head is flowing about 140CFM Bare Port. The cams are one off regrinds by Kent cams, both about 304 degrees and about 9.7mm full lift. Peak Power somewhere between 180 and 190 BHP @ Fly Standard compression ratio. Needs a visit to RR to get best out of cams and get the fuel pressure right
Looking For A Natural Gas Flow Meter
There are a few different types of flow meters that you can choose from, everything from the natural gas flow meter to the diesel fuel flow meter. If you are interested in getting a natural gas flow meter for instance, then there are a few companies in particular that you are going to want to check out.
Sierra Instruments
If you are looking for a high quality natural gas flow meter for a great price, Sierra Instruments is going to be an ideal option for you. They are a company that has been in the business for quite some time now which means you know that you can trust in them for their knowledge and expertise.
They manufacture only the most high performance mass flow meters and mass flow controllers for nearly any type of gas, liquid and steam application. Whenever you need an accurate and high quality flow measurement tool you are definitely going to want to head to Sierra Instruments for everything that you need.
Global Gas Products
Another company that you may want to go through for a natural gas flow meter is Global Gas Products. They not only feature a natural gas flow meter selection but as well Actaris metering systems which use Metris gas meters designed to offer modular flexibility and measurement accuracy for residential to light commercial applications and which are available in three different versions so you have more versatility and variety here.
They have been supplying the North American market since the 90s. Their clients range from worldwide manufactures and international corporations to small engineering firms all benefiting from their hands-on customer service driven approach.
The process of finding a natural gas flow meter is one that really does not have to be difficult, and by shopping at these sorts of companies you will definitely make it as quick and easy on yourself as possible. Just make sure that you take time to ensure that you are dealing with the right company so that you can find the best quality flow meter and at the best price as well.
Make sure that you find a company that has years of experience behind them and which is going to offer you the experience and knowledge that you are looking for. This way you will be coming out of it all with the best possible results and ensure that you have a flow meter that is going to last you through the years.