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ONICON Measurement Solutions Acquisition

Effective April 24, 2019 ONICON Measurement Solutions is pleased to announce the company has been acquired by the TASI Group ( ). The TASI Group is a privately-owned industrial business focused on Test, Measurement, Inspection, and Assembly instruments and equipment. All ONICON Measurement Solutions business units (ONICON, Air Monitor, Fox Thermal, Seametrics, Greyline and Pulsar Process Measurement) are included in this transaction. The ONICON Measurement Solutions companies will become part of the existing TASI Flow Group of companies which are currently comprised of AW-Lake Company, Exact Dispensing Systems, KEM GmbH, Litremeter, SignalFire Wireless Telemetry, and Vogtlin Instruments. John Norris, current president of ONICON Measurement Solutions, was named as President of the TASI Flow Group and will report to John McKenna, TASI Group President and CEO.


John Norris comments that “ONICON Measurements Solutions joining TASI Flow is a great next step in our continuing development as a premier flow and level measurement business. Together we have an impressive and extensive technology offering to better serve our customers around the globe and fuel further growth.”

All ONICON Measurement Solutions companies will continue to serve their customers by manufacturing quality flow and energy measurement devices and will honor their commitments to their customers with excellent customer service. The ONICON family of companies is excited about this acquisition and looks forward to continued business with you going forward.

Frequently Asked Questions

Has ONICON been acquired?

Yes. Effective April 24, 2019 ONICON became part of the TASI Group. This is a large, multi-national, company with businesses focused on Test, Measurement, Inspection and Assembly instruments and equipment. They have a significant Flow Group that we will be joining. It is a privately held, family owned business that has been in existence for many years.

Does this include all ONICON companies (ONICON, Greyline, Pulsar, Fox Thermal, Air Monitor, and Seametrics)?


What changes will happen to the business?

In the short term, we will have to suspend shipments of products and perform a physical inventory of the business. This should last no more than 2-3 days. Normal shipments should commence by April 29, at all facilities.

In the longer term, we will be the major part of the TASI Flow Group of companies. We are expected to continue to execute our plans and to be successful in the market.

Is a move contemplated?

No move is contemplated.

Any changes to how we order products?

Not in the foreseeable future.

Is it possible to gain access to other TASI Flow Group products through ONICON?

It is too early to tell. Please forward to sales management.

Have the company names changed? Will we need a new W-9? Will your Remit-to address change?

No changes are anticipated in how we do business together.

Explore all the brands in the TASI Flow Group below:

Air Monitor

Air Monitor has been delivering airflow measurement solutions since 1967 – 50 years! We are the premier solutions provider for the Commercial HVAC, Industrial Process, and Power Generation markets. We are the only dedicated airflow solutions provider with expertise in differential pressure and thermal dispersion measurement technologies.

AW-Lake Company

AW-Lake Company manufactures inline, positive displacement, mass Coriolis, variable area and turbine flow meters with an impressive array of electronic output and control options including; electronic sensors, inline optical sensors, flow switches/alarms and transmitters. The company’s flow monitoring products can be found in a broad array of market applications in the oil & gas, transportation, industrial, process, sanitary and medical/life sciences market segments.

Exact Dispensing Systems

Since 1978, Exact Dispensing Systems have designed and manufactured high quality equipment for the dispensing of single component fluids and plural component reactive resins such as epoxies, urethanes and silicones. Their materials and application expertise helps clients make the best decisions regarding their specific dispensing application. The EXACT staff members always take the time to understand the customer’s process requirements and then develop a valid, sensible, cost-effective dispensing solution to meet those needs.

Fox Thermal

After more than 20 years of manufacturing thermal gas mass flowmeters, Fox Thermal continues to lead the market in innovative, reliable, accurate, and full-featured flow meters. Our exceptional team of mechanical, electronic, and software engineers have helped to shape the thermal mass flow measurement industry.


Greyline is a worldwide leader in ultrasonic instrumentation for industrial and environmental markets. We develop, manufacture and market industrial flow and level monitoring instruments including ultrasonic level transmitters, flow meters and open channel flow meters. Greyline’s primary market is environmental – especially water and wastewater treatment systems.

KEM Küppers Elektromechanik GmbH

With more than 50 years of experience, complemented by innovative and customer-specific product development, KEM Küppers Elektromechanik GmbH is an expert in flow measuring technology and calibration. KEM is an independent, vertically integrated manufacturer that designs and produces standard and customized mechanical or static flow meter solutions.

Litre Meter

Litre Meter has been manufacturing flow meters since 1975 and positive displacement flow meters since 1986. This reservoir of knowledge is used to expertly select the appropriate meter technology and provide effective flow measurement solutions. Main markets are chemical injection and hydraulic applications in the Oil & Gas sector worldwide.


ONICON Incorporated has been delivering market leading flow and energy measurement products since 1987. For more than 30 years we have been exclusively focused on delivering quality engineered flow and energy measurement instruments for hydronic heating and cooling systems. Our broad range of product solutions are wet-calibrated, fully programmed for your application, and ready to use right out of the box.

Pulsar Process Measurement

Pulsar Process Measurement Ltd manufactures and supplies level, volume, open channel flow, pipe flow, sludge interface measurement and pump control instrumentation. Since 1997, Pulsar has risen to become one of the world-leading non-contacting measurement instrumentation manufacturers and their products are used in a wide variety of industries and applications worldwide.


Seametrics, an ONICON Measurement Solutions business, is a designer and manufacturer of a wide variety of flow metering and submersible sensor products. Since 1990 we have provided innovative solutions to users in irrigation, fracking, water treatment, groundwater, surface water, and chemical processing applications. Our products have a reputation for durability and accuracy at a competitive price, and are sold through a network of domestic and international distributors.

Sierra Instruments

A global leader in flow measurement and control for over 45 years, Sierra Instruments designs and manufactures fluid flow measurement and control solutions for customers spanning across global industries as diverse as scientific research, oil & gas, energy management, semiconductor, clean energy, aerospace and biotech to name a few. Sierra provides state-of-the-art calibration and fast localized service. With over 150 locations in over 50 countries, Sierra is uniquely positioned to provide innovative products and lifetime support for the leading companies of today and the growth enterprises of tomorrow.


SignalFire’s unique Open Architecture Wireless Mesh Network permits users to create wireless sensor networks using the sensors and actuators best suited for the job rather than a wireless option provided by a sensor vendor. SignalFire’s intrinsically safe battery powered nodes can power both the attached sensors and the wireless system making the system truly wireless.

Vögtlin Instruments GmbH

Vögtlin Instruments GmbH is a Swiss designer of gas flow measurement and control instruments. Vögtlin has over 25 years of experience in designing and manufacturing high precision thermal mass flow meters and controllers, variable area flow meters and control valves. The core competence on calibration and OEM solutions together with the application expertise throughout its worldwide sales partner network make Vögtlin a strongly respected player in various industrial fields such as medical, biotechnology, surface treatment, coating & hardening and new energy.

TTFM 1.0 Transit Time Flow Meter

TTFM 1.0 Transit Time Flowmeter

  • Non-Contacting Clamp-on Ultrasonic Transducers
  • Works on Metal and Plastic Pipes
  • Large Backlit Flow Rate Display and Totalizer
  • Isolated 4-20mA Output
  • Built-in 5-Key Calibrator
  • 2 Programmable Control Relays
  • Optional 2 Million Point Data Logger

DFM 6.1 Doppler Flow Meter

DFM 5.1 Doppler Flow Meter

  • Non-Contacting Ultrasonic Sensor
  • Accurate and Verifiable
  • Built-in 2-million point Data Logger and Windows Software
  • USB Outputs to Flash Memory Sticks
  • Isolated 4-20mA/0-5V Output
  • 2 Programmable Control Relays
  • Simple 5-key Calibration with Language Selection

AVFM 5.0 Area-Velocity Flow Monitor

AVFM 5.0 Area-Velocity Flow Monitor

  • For Open Channels and Pipes No Flume or Weir Required
  • Ultrasonic - Measures Velocity + Levelto Calculate Flow
  • Works in partially filled and surcharged pipes
  • 3 Isolated 4-20mA Outputs(Flow, Level and Velocity)
  • Isolated 4-20mA/0-5V Output
  • Totalizer and 2 Control Relays
  • Optional Intrinsically Safe Sensor
  • Optional built-in 2-million point Data Logger

Greyline Instruments, Inc. Privacy Policy – May 2018

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All questions, comments, requests and complaints regarding this Policy and the information we hold are welcome and should be addressed to us at This email address is being protected from spambots. You need JavaScript enabled to view it. or in writing at:

General Manager
Greyline Instruments, Inc.
11451 Belcher Road South
Largo, FL 33773

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We're sorry, the product or article you requested has been moved.

Find Application Notes and Case Studies here.

If you are looking for a product select one of the categories below.

or find it in the list below.

Ultrasonic Flow Meters:

DFM 6.1 Doppler Flow Meter

DFM 6.1 Doppler
Flow Meter

Product details
PDFM 5.1 Portable Doppler Flow Meter

PDFM 5.1 Portable
Doppler Flow Meter

Product details
TTFM 6.1 Transit Time Flowmeter

TTFM 6.1 Transit
Time Flowmeter

Product details
PTFM 1.0 Portable Transit Time Flow Meter

PTFM 1.0 Portable
Transit Time Flow Meter

Product details
DFS 5.1 Doppler Flow Switch

DFS 5.1 Doppler
Flow Switch

Product details
SFM 6.1 Ultrasonic Slurry Flow Meter

SFM 6.1 Ultrasonic
Slurry Flow Meter

Product details
ISM 5.0 Insertion Magmeter

ISM 5.0 Insertion Magmeter

Product details
Portaflow PT400 Portable Transit Time Flow Meter

Portaflow PT400
Portable Transit Time Flow Meter

Product details

Open Channel Flow:

Stingray 2.0 Portable Level-Velocity Logger

Stingray 2.0 Portable
Level-Velocity Logger

Product details
MantaRay Portable Area-Velocity Flow Meter

MantaRay Portable
Area-Velocity Flow Meter

Product details
AVFM 6.1 Area-Velocity Flow Monitor

AVFM 6.1 Area-Velocity
Flow Monitor

Product details
OCF 5.0 Open Channel Flow Monitor

OCF 5.0 Open Channel
Flow Monitor

Product details

Level Monitoring:

DLT 2.0 Differential Level Transmitter

DLT 2.0 Differential
Level Transmitter

Product details
SLT 5.0 Ultrasonic Level and Flow Monitor

SLT 5.0 Ultrasonic Level and Flow Monitor

Product details
LIT25 Level Indicating Transmitter

LIT25 Level
Indicating Transmitter

Product details
PSL 5.0 Hybrid Pump Station Level Controller

PSL 5.0 Hybrid
Pump Station Level Controller

Product details

Ultrasonic Level

Ultrasonic Level

Greyline ultrasonic sensors are mounted at the top of a tank or in a position above the liquid being measured. The sensor continuously transmits pulses of high frequency sound (typically 42 kHz) which travel away from the sensor, hit the surface of the liquid and return to the sensor.

The instrument electronics measure the time it takes from transmitted sound to return of the echo. With reference to the speed of sound in air, the exact distance of the liquid surface from the sensor can be calculated with high accuracy (±0.25% of maximum range).

Since the speed of sound is affected by air temperature, Greyline ultrasonic level sensors include a built-in temperature sensor. Level/distance measurements are automatically temperature compensated throughout the operating temperature range of the sensor.

The sensor should be positioned so that it has a clear "view" of the liquid surface and away from ladders, pipes or other obstructions. Greyline recommends 1 ft. from the sidewall for every 10 ft. depth (300 mm for every 3 m depth). False echoes from agitators (sweeping under the sensor), turbulence and waves can be filtered and disregarded by the instrument.

Greyline models range from simple 4-20mA level indicating transmitters, to sophisticated monitoring, controlling and data logging models. Return to Greyline Products for Level model details and specifications. For information on a wide range of level instrument technologies including ultrasonics, read Wastewater Level Measurement Techniques.

Update to the Pulsar/Greyline Coronavirus Response:

On March 23rd, Premier Doug Ford announced that all non-essential businesses in Ontario should close by the end of day, March 24th. Please rest assured that Greyline Instruments remains open to support your business and will continue to manufacture and support product as we serve essential markets and supply chains.

You can read our full COVID-19 response by clicking the link below. If you need us, we’re here for you. Please reach out if we can be of service.

Pulsar Greyline Integration


[December 2019] Pulsar Process Measurement Ltd are pleased to announce their amalgamation with Greyline Instruments Inc.

2020 is set to be an exciting year for both Pulsar and Greyline as they embark on their new journey together.


Application Note - End-To-End Solutions for The Township of Edwardsburgh/Cardinal

From sewage pump stations in the collection system, through final treated effluent, the Township of Edwardsburgh/Cardinal deploys Greyline flow and level instruments...


Application Note - Doppler for Fly Ash Slurry Flow

Limestone Slurry is abrasive therefore in-line flowmeters are not practical. Non-contacting Doppler Flowmeters can be used both on the fly ash slurry supply lines and on "used" or recirculated slurry...

Non-Contacting Flow Meters for Dredging Slurry 

Case Study - Dredge Manufacturers Improve Operating Efficiency with Greyline Clamp-on Flow Meters 

Dredge operators need accurate real-time flow information to properly manage production. But dredging slurries are very abrasive and pumped at high velocity so flow measurement is difficult. Manufacturers find the solution with Greyline clamp-on flowmeters...

Solution for Acidic Flow Measurement

Case Study - Minera Escondida, Chile
Non-Contacting Flow Solution for Heap Leach Mining

The world's largest single producer of copper was faced with a challenge in their heap leaching process in the Atacama Desert of northern Chile. Finding an accurate, reliable non-contacting flow meter was a difficult task...

Thurston County Chooses Greyline Flow Meters

Thurson County, Washington
Comments on Greyline Flowmeters

Since 2007 Thurston County has deployed Greyline Area-Velocity Flow Meters in open channels resulting in thousands of dollars in savings every year. Read their comments here...

Pump Station Call Outs Solved

Case Study - Town of Eckville Stops Pump Station Call Outs With New PSL 5.0 Pump Station Level Controllers

Town operators were plagued by high level alarm call outs at two new sewage lift stations. Read how they used Greyline's hybrid ultrasonic level controllers with dual sensor capability to put an end to level alarms.

Clamp-on Sensors Solve Crude Oil Flow Problems

Case Study - Clamp-on Flowmeters
Solve Flow Problems At Crude Oil Battery Site

Wax and solids build-up were plugging off pipes and in-line flowmeters at this oil battery site in Alberta. Read how Petrobakken Energy solved the problem by switching to Greyline DFM 5.0 Doppler Flow Meters with non-contacting ultrasonic sensors.

Wastewater Level Measurement Techniques

Wastewater Level Measurement Techniques

Chapter 36 from the Wiley & Sons publication: Environmental Instrumentation and Analysis Handbook. This is an informative summary of applications and level instrumentation used in Wastewater Treatment Plants.

Golf Course Irrigation with Greyline TTFM 1.0 Transit Time Flowmeter

Case Study - Golf Course Irrigation
Flow Monitoring from Outside a Pipe

A new TTFM 1.0 Transit Time Flowmeter monitors and logs irrigation water pumped to sprinklers at Summerheights Golf Links. The clamp-on flowmeter is used to comply with a Ministry of Environment permit.

Irrigation Water Flow Meter

Case Study - Irrigation Water Flow Measurement 
For Open Channels and Partially Filled Pipes

Greyline AVFM Area-Velocity Flow Meters monitor and totalize irrigation water distributed through a network of canals, channels and pipelines in the United Irrigation District.

Submerged Flow Solution

Case Study - Solution for Irrigation Water
Flow Monitoring in Submerged Culverts

Greyline DFM 5.0 Doppler Flow Meters with waterproof ultrasonic sensors measure flow in submerged concrete culverts in the Raymond Irrigation District in Alberta, Canada.

Area-Velocity Flowmeters in Denmark 

Case Study - Area-Velocity Flowmeters in Denmark

Greyline AVFM Area-Velocity Flow Meters are installed thoughout the country by Teletronic Denmark to monitor municipal sewage and stormwater. Application photos and descriptions illustrate flow monitoring in manholes and open channels.

Quarry De-Watering Flowmeter 

Case Study - Quarry Dewatering Flowmeter
at the Bray Quarry in Eastern Ontario

A Greyline AVFM Area-Velocity Flow Meter monitors and data logs water discharged from the Bray Quarry to the South Raisin River. The Quarry is required to measure flow for environmental permit compliance.

Dear Greyline...

DLT 2.0 Differential Level Transmitter
Open letter from a Greyline customer

The septage receiving station in Whynott's Settlement, Nova Scotia needed a simple, compact solution to control VFD-driven vertical turbine pumps, chlorine injection plus flow through a V-Notch Weir with display and 4-20mA outputs... 
Solution: the Greyline DLT 2.0 Differential Level Transmitter

Troubleshooting with Portable Greyline Flowmeters

Case Study - Flowmeter Troubleshooting 
at The Township of North Glengarry

An Ontario municipality deploys Greyline portable flowmeters to solve flow rate discrepancies between a magmeter installed on the forcemain in their pump station and an open channel flowmeter at the sewage lagoon.

Greyline OCF for WWTP Influent Flow 

OCF 5.0 Open Channel Flow Monitors 
Monitor Infulent at Long Sault WWTP Plant

After 16 years of service, the Long Sault WWTP replaced two older Greyline Open Channel Flow Monitors with new data logging OCF 5.0 models. This SBR treatment plant's influent is measured with flow through two 6" Parshall Flumes.

Greyline SLT for Culligan Water Plant Tank Level 

SLT32 Ultrasonic Level Monitors
for Water Bottling Plant Level Control

Culligan Water installs Greyline SLT32 Level Monitors to control tank levels in their bottling plant in Calgary, Alberta. With non-contacting ultrasonic sensors the SLT32's control fill and discharge valves in five tanks containing spring water, reverse osmosis water and distilled water.

Water Accountability - Using Greyline Stingrays to Identify Excess Flow

Case Study - Water Accountability 
Portable Monitoring Instruments Solve Flow Rate Mystery

The Glen Walter Sewage Collection System was built to service 1,080 customers in 1989. At the time the population was 850 but by 1995 the sewage treatment plant had already reached capacity. Plant operators and the municipality had concerns about the excess flow...

Greyline Doppler for Sand Slurry Flow

DFM 5.0 Doppler Flow Meter
for Frac Sand Slurry Flow Monitoring

CanFrac Sands Ltd. of Lloydmister, Saskatchewan install a Greyline DFM 5.0 Doppler Flow Meter to measure fracturing sand slurry when their in-line flowmeters were being damaged by the  abrasive slurry.

Greyline AVFM for Lagoon Discharge Flow

AVFM 5.0 Area-Velocity Flow Meter  
Monitors Sewage Lagoon Discharge Flow

The Township of South Glengarry installs a new Greyline AVFM 5.0 Area-Velocity Flow Meter to measure continuous discharge from their municipal sewage lagoon. The sealed ultrasonic sensor is mounted in a horizontal 12" PVC pipe. The AVFM replaced a magnetic flowmeter that was unable to measure seasonal low flow rates.

Greyline LIT for Swimming Pool Level Control 

LIT25 Level Indicating Transmitter  
Controls Swimming Pool Level

A Surge Tank is used at the Okotokes Rec Centre Swimming Pool to regulate pool level. By monitoring level in a surge tank the non-contacting Greyline LIT25 Level Indicating Transmitter controls makeup water flow through a solenoid valve.  



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Greyline is a worldwide leader in ultrasonic instrumentation for wastewater, industrial, and environmental markets. Since 1986 we have developed, manufactured and marketed industrial flow and level monitoring instruments including ultrasonic level transmitters, clamp-on ultrasonic flow meters, and open channel flow meters.

Greyline’s primary market is environmental - especially water and wastewater treatment systems. Customers include industry and municipalities.

Modern research facilities at Greyline include closed pipe and open channel flow systems. With years of steady growth, Greyline products are sold and supported worldwide. 

Pulsar Process Measurement Ltd are pleased to announce their amalgamation with Greyline Instruments Inc.

Read more about the amalgamation here.

Pulsar Greyline Merger


Greyline Instruments Inc. Canada
16456 Sixsmith Drive, Long Sault, Ont. K0C 1P0
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Greyline Instruments Inc. United States
11451 Belcher Road South, Largo, FL 33773
Tel: 315-788-9500 • Toll Free: 888-473-9546
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