New white paper: Advancing mass flow technology with multi-range and multi-gas programmability

March 10th, 2017 No comments

In the past decade, the availability of mass flow controllers that incorporate multi-range and multi-gas programmability has redefined the flow control industry. This new white paper discusses the impact this new technology has had on how MFCs are engineered into different systems, and the way plants have modified their operations to take full advantage of multi-range and multi-gas programmability.

The white paper also provides useful and informative details on Brooks’ MultiFlo™ technology in thermal mass flow controllers: how MultiFlo™ provides superior process gas accuracy with the help of data generated by over thousands of different data points over the course of 10 years. The result: a single MultiFlo™-capable MFC to replace many different MFCs no matter what gas or range is required, thus reducing inventory of replacement MFCs.

Download White Paper: Multi-range and multi-gas programmability

How to Get the Best Possible Accuracy for Carbon Dioxide Applications

March 10th, 2017 No comments

When buying a mass flow controller, the accuracy specification that is published on the data sheet is important criteria to evaluate. In fact, accuracy is so important that you need to look beyond the published accuracy statement because the published accuracy does not necessarily represent the actual process gas accuracy that will be achieved.

Nothing Like the Real Thing
Calibrations are typically done against a reference device or calibration standard using a surrogate calibration gas such as nitrogen or air. Surrogate gasses are used because it can be difficult and expensive to test and calibrate a device on the actual process gas. When a surrogate gas is used, a conversion factor or conversion function is applied to that surrogate gas calibration to set up the device for the specified process gas. This conversion factor is based on the specific heat of the process gas vs the specific heat of the calibration gas. This conversion factor approach may introduce some additional inaccuracy depending on the properties of the process gas. There’s nothing like the real thing… The best possible accuracy is delivered when the device is calibrated directly on the customer specified process gas and at the process conditions.

Characteristics of Carbon Dioxide
Carbon Dioxide is a refrigerant which makes its conversion factor (specific heat) highly pressure dependent.

specific heat of CO2

Specific Heat of CO2 by Temperature & Pressure

The specific heat of CO2 varies over temperature and pressure (see below), so the use of a single “calibration”, “sensor” or “correction” factor will result in additional inaccuracies at different temperatures and pressures. At higher temperatures and pressures the variation in the specific heat increases dramatically.

MFC users that have the ability to determine the actual CO2 flow rate have verified that the reported flow rate from a CO2 MFC calibrated on a surrogate gas is not accurate. Many users need to “adjust” the setpoint to compensate for the offset and need to determine a new offset for each new temperature, pressure and flow rate application.

How We Do It
At Brooks Instrument, we use traceable calibration standards for all our mass flow calibrations to ensure that we meet our published specification. And, to provide our customers with the most accurate mass flow controllers for carbon dioxide applications, we calibrate the 5800 Series, SLA5800 Series and SLAMf Series MFCs on carbon dioxide (i.e. Calibrated on the real thing J). This allows the user to control the exact desired amount of CO2 with no offsets or hassles. Brooks Instrument also uses actual gas calibrations for Argon, Helium, Hydrogen and Nitrogen.

For additional information on mass flow controller accuracy see our blog post, “Understanding Mass Flow Controller Accuracy.”

For assistance selecting the most accurate MFC for your application, please contact our Applications Engineering team or your local Brooks Instrument representative.

An Easy, Turnkey Solution to Powering and Controlling Mass Flow Controllers

February 27th, 2017 No comments

When buying a mass flow controller (MFC) or mass flow meter (MFM), the attention is usually on selecting and sizing the correct device for the application while power and control is often a secondary thought. When the question of how to power and control one or more devices arises, my top recommendation is the 0254 Four Channel Power Supply, Readout & Set Point Controller. Brooks 0254 Four Channel Power Supply, Readout & Set Point ControllerThis adaptable and configurable supply will also work with Brooks Instrument pressure & vacuum products or virtually any product that requires a standard DC power supply and has a voltage or mA I/O signal, including other manufacturers’ devices.

Configuring the 0254 Power Supply

Configuration of the 0254 is very simple to complete by using the front panel push-button menu. I/O types can also be mixed and matched: such as utilizing one device with voltage signals, and another device with mA signals on the same 0254. The 0254 is also ideal for a small lab environment, as it can operate up to 4 devices from a single controller.

The 0254 is a power and control device that can be configured for a variety of inputs and outputs, including virtually any analog I/O. It can also be ordered with either a 24 Vdc supply or a ±15 Vdc supply. This power supply is now an interchangeable transformer supply, similar to your laptop supply. You can buy one DC power supply or buy both depending on your requirements. This means that a single 0254 will work with an entire line of meters. This adaptable and configurable supply helps ensure the right supply is selected every time.

Keeping Voltage & Cable Requirements in Mind

An important thing to keep in mind is the requirement for voltage adapters when your device uses voltage I/O. The voltage adapters are required when using any Brooks Instrument voltage I/O device with standard Brooks Instrument cables (details on wiring and the voltage adapters can be found in the 0254 installation and operation manual available for download from our website).

Of course cables will be necessary, and most meters sold by Brooks Instrument use the same pin out configurations and the same cables. While most cables and meters could be considered interchangeable, always verify the pin outs and correct cables to ensure proper operation.

I personally really like working with the 0254 because it has simplified our customer’s choice when it comes to the power supply and readout and control that’s needed for their application. Some other features that the 0254 is capable of include:

  • Individually configurable inputs and outputs
  • Selectable measurement units
  • Selection of displayed variable
  • Monitoring of actual voltage or mA
  • Blending
  • Batch control
  • Serial communications
  • Data-logging
  • Valve override control

Our global team of flow and pressure experts is always ready to help so please contact us anytime.

Certifications of Elastomer O-Rings for Mass Flow Controllers Explained

January 17th, 2017 No comments

Mass Flow Controllers (MFCs) are used in many applications that require different certification requirements for materials that could come into contact with anything going into the end product. For gas control in bioreactors, gas is being controlled by MFCs in a gas box, in open frame systems, or mounted on a skid. Process gasses go through the MFC and into the bioreactor to control the cell growth and cannot be contaminated by the materials in the gas supply components.certifications of o-rings in mass flow controllers

Many MFCs use elastomer sealing materials and it is important to make sure you have materials that are certified to be safe for the application. For example, our SLA Series MFCs offer USP Class VI O-rings in two different materials (Viton and EPDM – See blog on elastomer selection). So what does this even mean?

USP Class VI
USP stands for U.S. Pharmacopeia, a private (non-government) organization that ‘promotes the public health by establishing state-of-the-art standards to ensure the quality of medicines and other health care technologies’. For plastics, they have 6 different classes based on duration and application. Class VI is the most stringent and requires three tests:

  1. Systemic injection test
  2. Intracutaneous test and
  3. Implantation tests

In order to pass the Class VI standards, the product/material must exhibit a very low level of toxicity by passing all the tests requirements when tested according to ISO 10993.

The FDA requires testing of finished devices, however, the demonstration of biocompatibility of materials according to USP Class VI standards is provided as an aid to device manufacturers in their material selection process.

ADI-Free / BSE-Free / TSE-Free
Another up and coming requirement is ADI free (BSE / TSE free). This is to certify that the raw materials used in production of the elastomer contain no Animal Derived Ingredients (ADI) and are therefore Bovine Spongiform Encephalopathy (BSE) Free and Transmissible Spongiform Encephalopathy (TSE) Free with respect to source, manufacture and treatment. This assures the user that there is no path for these pathogens to contact their process or product. This is a statement from manufacturers certifying that there no substance of animal origin used to manufacture the product.

When you see ‘CFR 21 FDA 177.2600’ on MFC O-rings it means that it is on the FDA list of base elastomers that are recognized as inherently safe and classified as GRAS (Generally Recognized as Safe).

Of course, we here at Brooks Instrument are always happy to answer questions around our compliance with these standards in our products so feel free to contact us.

IP, NEMA: What does it all mean and what’s best for my wash-down application?

January 3rd, 2017 No comments

We are going to take a look at the IP and NEMA ratings and what they mean. With this information you should be able to decide what minimum level of protection you need for your application.SLAMf Mass Flow Controllers

Let’s start with the basics. What does IP and NEMA stand for? IP stands for ingress protection and NEMA stands for National Electrical Manufacturers Association. Both IP and NEMA are rating systems for equipment that might be exposed to liquids, rain, ice, corrosion and contaminates such as dust.

IP Rating System

An IP number contains two numbers (i.e. IP65) in most instances which relate to the level of protection provided by an enclosure or housing. The first number relates to protection from solids as follows: Read more…

At the Cusp of Exciting New Technology

December 19th, 2016 Comments off

What do the Corvette and today’s new jet engines have in common (besides both going really fast)?

Answer: They both use carbon fiber materials in their construction to be lighter, more efficient and, of course, faster still.

Why, you might ask, is a flow measurement and control company like Brooks Instrument so interested in these materials?

Why Ceramic Matrix Composites (CMC)?
The material being manufactured for today’s jet engines is a Ceramic Matrix Composite or CMC. The making of these CMCs require multiple gas streams during the manufacturing process. Brooks Instrument thermal mass flow controllers are used on these gas process lines extensively throughout the entire procedure. The most common CMC configuration is a composite of tiny interwoven ceramic silicon carbon fiber embedded and intertwined in a silicon carbon-carbon ceramic matrix giving it “supernatural” capabilities. Specifically, the resultant material becomes extremely heat resistant, more so than its high-alloy metal predecessor. This ceramic material will not decompose up to 4900°F, doubling the heat resistance of the high-alloy metals. The CMC material is also lightweight as it is one third the density of conventional metal alloys used in jet engines. The “Matrix” gives the material its strength, outperforming its metal competitors.

ge9x

GE9X Engine Cutaway

Manufacturing CMCs
As you can imagine, manufacturing a complex material like this comes with its challenges. And that’s where our latest advancement in mass flow technology delivers thousands of dollars of savings in process downtime.

Our GF40 Series and GF80 Series mass flow controllers are used for the “standard” gas streams like N2 (nitrogen), CO2 (carbon dioxide) and other purge gases. These gas lines make up most of the processing gas for manufacturing. There are, however, a couple of major process gases used that present particular complications. These gases, also, are essential to the success of the final product.

The two gases in question are BCL3 (boron trichloride) and SiCL3 (trichlorosilane) which are used as precursor material during Chemical Vapor Infiltration (CVI), an integral part of the creation of a CMC. These gases pose inherent risk during the process as they have low vapor pressures meaning they want to be a liquid most of the time. Additionally, they are difficult to manage as they react quickly with moisture in the air to create a corrosive concoction. They must be tightly monitored and controlled to avoid failure in the process. The accuracy of the thermal mass flow controllers (MFCs) used with these two gases must be carefully scrutinized requiring regular and frequent process shutdown and MFC flow verification. This can cost upwards of $10K per hour.

Here is where the Brooks solution is realized. We have a product designed to enable in-situ gas flow verification with no need to shut down the process for MFC health checks. The GF135 Series supplies continuous process flow data during the entire process using an on-board ROD (Rate of Decay) secondary flow measurement. The user can take advantage of:

  • Enhanced process gas accuracy
  • Market leading pressure transient performance, and
  • MFC health indicators such as automatic trending of sensor stability and valve performance/shutdown (leak-by)

Each GF135 is gas specific and proven on the actual gas it is set up for – no guessing or inferences here. We know it works because we brought in the gases to our lab and used them for proof positive. The GF135 saves time and money and is the only product of its kind in the industry. And it simplifies the process!

ge9x

GE9X Commercial Aircraft Engine

CMCs are expensive to make so cost cutting is important and in demand in the industry. The GF135 is the solution for BCL3 and SiCL3 gases however it can also be used on other difficult to manage gases used in the process of making CMCs like NH3 (Ammonia).

So what’s next in our world of innovation? Warp Drive perhaps? Doesn’t this GE9X CMC laden jet engine manufactured by GE Aviation look like the Starship Enterprise?

Flow Totalization in Gas Usage Monitoring

October 31st, 2016 Comments off

A common application where accurate flow totalization is required is gas usage monitoring. In this application there is typically a single source of gas being shared by several different users or locations within a facility. To account for usage, or allocate costs properly, the facility needs to monitor the amount of gas consumed by each user.

Typical Installation

A typical installation for this application includes several flow meters, secondary electronics with totalizer function cabling from each device connected to a central monitoring system. The totalizer gets a flow signal from the flow meter, calculates the totalized flow and sends that value to the central monitoring system.

Gas Usage Monitoring Diagram

Typical gas usage monitoring installation

With this approach the accuracy of the totalized flow may not be optimized. There may be some additional error due to resolution of the analog to digital converters (ADC) and signal noise. The user also needs to be sure the analog signals were calibrated properly and that they match the span and time units of the flow meters. Signal filtering, signal cutoffs, sample rates and sample period can also have an impact. All of these factors could lead to improper billing or cost allocation. There is also additional hardware and cabling costs with this approach that could be avoided.

A Lower Cost Approach

An alternate approach uses digital mass flow meters, like the Brooks SLA Series, which calculate the totalized flow value internally. With this approach, no additional inaccuracy is introduced with a secondary calculation or digital to analog conversion.

Gas Usage Monitoring Diagram Using Brooks SLA Series MFCs

Gas usage monitoring installation using Brooks SLA Series Mass Flow Meters

 

 

 

 

 

 

 

 

 

Another advantage of this approach is that the user is able feed the totalized flow value directly to the gas monitoring system via digital communication. This eliminates the need for the totalizers and simplifies the wiring, therefore reducing the total installed cost of the system.

Validating Totalized Flow Accuracy

To confirm the totalized flow accuracy of the SLA Series mass flow meters, Brooks Instrument used a Bell-Prover (traceable flow calibration standard) and a formal totalizer verification process. With this approach we were able to demonstrate totalized flow accuracies of better than 1.2%. The chart below summarizes the data for 12 devices each run at four (4) flow rates.

Brooks Mass Flow Meter Error Rate Date

 

 

 

 

 

 

Brooks Instrument SLA Series mass flow devices are available with a variety of digital communication protocols and a range of options to satisfy even the most difficult applications including hazardous area and outdoor installations.

To learn more about our proven mass flow devices for gas usage monitoring or any other application where totalized flow is required, please contact us.

Using LabVIEW™ Software to Interface with Brooks Instrument Thermal Mass Flow Controllers

September 15th, 2016 Comments off
brooks-gf40-mfc-labview

Brooks Instrument Model GF40 MFCs (qty 4) with Multi-drop Cables

LabVIEW™, a National Instruments software development tool, is widely used to create software applications that monitor and control a variety of sensors and control devices. It is very common to find a laboratory, university, or a pilot manufacturing plant using one of these applications to interface with mass flow devices. LabVIEW™ software can interface with a Brooks Instrument mass flow device through different forms of data acquisition. The most popular forms of data acquisition used with Brooks Instrument mass flow devices are described below.

Analog Signal Interface

The chances are good that LabVIEW™ software users have analog to digital I/O cards, and can run their MFCs utilizing the 0-5 volt or 4-20 mA analog signaling via LabVIEW™. This is recommended for anyone who may not be ready to move to direct digital control.

national instruments power supply

Power Supply by National Instruments

RS485 Digital Signal Interface

Brooks Instrument mass flow devices configured with the ‘S’ communications option provide RS485 digital communications via the 15-pin D connector. The RS485 digital signal can be passed directly to the computer running LabVIEW™ through a serial RS485 converter. The GF40, GF80 and SLA Series MFCs from Brooks Instrument can be configured with the ‘S’ communications option.

    • Brooks Instrument provides a free set of VI files for use with LabVIEW™ software via our website which can be loaded directly into the LabVIEW™ application, and provide the building blocks for creating a LabVIEW™ software control interface utilizing the S-Protocol digital command structure. Additionally, a Brooks LabVIEW™ DLL file is included so these building blocks can be referenced and used within a LabVIEW™ application program interface (API).
    • Another possibility is to use the Brooks Instrument Smart DDE (Dynamic Data Exchange) software as an alternate tool to create links between the LabVIEW™ application and the GF40, GF80 or SLA Series flow, control, and configuration parameters. Additionally, the user can leverage Windows applications (Excel, Word, Access) and programming languages ( C++, C#, Visual Basic) and SCADA programs from suppliers such as Allesco and Millennium Systems International. No knowledge of the mass flow device S-Protocol command structure is required. With Smart DDE, the user gets direct access to the required data fields. This is not a 100% turnkey solution, but reduces the amount of coding required to communicate with and control the MFC.

DeviceNet Digital Signal Interface

GF40, GF80 and SLA devices configured for DeviceNet digital communications can also be controlled via the LabVIEW™ application. Note that this requires a National Instruments DeviceNet interface card and associated drivers and software, which provide support for developing application interfaces using LabVIEW™ software for Windows and LabVIEW™ Real-Time. The following is taken from the National Instruments website:

National Instruments DeviceNet for Control interfaces are for applications that manage and control other DeviceNet devices on the network. These interfaces, offered in one-port versions for PCI and PXI, provide full master (scanner) functionality to DeviceNet networks. All NI DeviceNet interfaces include the NI-Industrial Communications for DeviceNet driver software, which features easy access to device data and streamlined explicit messaging. Use a real-time controller such as PXI and NI industrial controllers to create deterministic control applications with the NI LabVIEW Real-Time Module.

So, don’t be afraid to go digital. The digital aspect of our mass flow devices include many on-board functions that work in the background and make the device superior even if the final flow signal is sent via analog signal (0-5 Vdc or 4-20 mA).

Successfully Managing Industrial Chlorinated Processes with Metal Sealed Mass Flow Controllers

August 9th, 2016 Comments off

Chlorine (CL2)Chlorine (CL2) is a member of the halogen elements group that is highly reactive and bonds easily with hydrogen to form HCL acid. HCL attacks stainless steel aggressively – literally passivating the surface of the stainless steel, and can render a thermal mass flow controller inoperative in a brief period of time. CL2 is used frequently in many applications from making PVC pipe and treating water to plasma etching a computer chip. CL2 is a critical process element in our world. CL2 mass flow controllers typically have a significant life span reduction which can be improved using tightly managed process controls. So what needs to be controlled in a CL2 process?

1) Leak test your system
The primary contaminant component for CL2 applications is air and its entrained moisture (water) content. To avoid this process “invasion” it is imperative that the entire system be leak tight at the onset of work. The best (and cheapest) way to do this is to pressurize the line with clean, dry nitrogen (N2) to 50 PSIG. Make sure the line is not blocked in any way with shut off valves, etc. Measure the line pressure as accurately as possible and allow the piping to stand in a static mode for a 24 hour period or longer if possible. Recheck the pressure reading to verify no decay has taken place. It is best to verify leak integrity in a temperature stable environment.

2) Pump purging before every start up and after every process run
Eliminating air content in the process line before CL2 is introduced is essential to a successful startup procedure. Purging the process path after a process run will further enhance the longevity of your CL2 mass flow controllers. Cycle-purging using dry N2 is the best method to accomplish the purging process. This is accomplished by raising the N2 purge gas line pressure to 30 PSIG and then exhaust to a small backpressure of 1-3 PSIG. This backpressure will protect the process line from back flow of air. This process should be repeated at least 15 times to evacuate as much air or other moisture bearing gas from even the smallest dead space in the line. Maintaining a high vacuum state in the process line after this this cycle- purging is completed will qualify a “clean” system for CL2 service.

3) Eliminate the possibility of contamination from the N2 purge source
The N2 purge source should be certified to have less than one part per million (1 PPM) of moisture/O2 in it. This should be verified periodically with in situ testing. It is best to use a dedicated N2 purge gas line for CL2 services. Ideally, specialized gas purifiers (as used in the semiconductor industry) should be used just prior to the point of process gas use as a primary precautionary method. These purifiers are a necessity to achieve better than 100 parts per billion moisture content which is the recommended “safe” level to minimize / eliminate the production of hydrochloric acid in the process stream.

4) Use the appropriate/best mass flow controllers for CL2 service
The ideal thermal mass flow controller for CL2 gas service is the Brooks Instrument metal sealed GF80 Series or GF100 Series. Metal seals eliminate the possibility of outgassing thru elastomeric o-rings, keeping air out of the flow stream. These products have essential functional components made of Hastelloy C-22 – flow sensor, valve seat, and valve orifice. Hastelloy C-22 is inherently corrosion resistant to CL2. Additionally the GF80 Series and GF100 Series products have a 10µ inch Ra surface finish or better for particle free function. The exceptional performance of the GF series is enhanced by our MultiFlo™ technology – gas and range programmability embedded in the electronics of each device. Actual CL2 gas was used to establish an empirical CL2 gas calibration table inherent in every GF Series product. The GF80 and GF100 Series will exceed your expectations for the best accuracy and performance in your CL2 application!

Are there direct replacements for Full-View® glass tube flow meters (models 1110, 1114, 1140, 1144)?

July 25th, 2016 Comments off
Full-View Glass Tube VA Flowmeter

Full-View® 1100 Series

With the obsolescence of Full-View® models 1110, 1114, 1140 and 1144, we are often asked for a direct dimensional flow meter replacement. The GT1306 (127,150mm) and GT1307(250mm) retro-fit meters will accommodate the same fit, form and function as the existing meters. Please note you will need the following information to complete a sizing and model configuration:

  • Original sizing and flow specs
  • Overall length and center to center dimensions
  • Connection type: either NPT or Flange and the orientation of the connections
  • Elastomer compatibility

You can access more details on replacement options here.