Use Electronic Pressure Controllers in Your Research Process Loop to Eliminate Droop, Boost, and Hysteresis

(re-blogged with permission from Brooks Instrument)

Gas pressure control is critical in many applications like life sciences and chemical/petrochemical research where flow is an integral part of the process. Brooks Instrument electronic pressure controllers can be used as they require flow to function. Compared to using a mechanical pressure regulator, electronic pressure controllers eliminate droop, boost and hysteresis, offering stable pressure control.

There are two configurations available for pressure control – upstream and downstream. This terminology is somewhat unique to Brooks Instrument electronic pressure controllers.

Downstream vs. Upstream Pressure Control

Downstream pressure controllers maintain the pressure downstream of the device itself, increasing flow to increase the pressure and decreasing flow to decrease the pressure. For this reason, this is called direct acting. This configuration is commonly called a standard pressure regulator. A downstream pressure controller acts very similar to a typical mass flow controller because they are both direct acting.
Upstream pressure controllers maintain the pressure upstream of the device itself, increasing flow to reduce the pressure and decreasing flow to increase the pressure. For this reason, this is called reverse acting. This configuration is commonly called a back pressure regulator in the industry.

Selecting and Sizing an Electronic Pressure Controller

The following information is required to select and size a Brooks Instrument electronic pressure controller:

• Process gas
• Maximum flow rate being used to maintain pressure -The “sweet spot” for pressure control is between 100 SCCM and 5 SLPM.
• Calibration pressure (maximum pressure to be controlled)
• Reference pressure (for upstream controllers the reference pressure is the downstream pressure and for downstream controllers the reference pressure is the upstream pressure)

As long as flow is present in a process you will typically find the need for some type of pressure control. Vessel sizes up to 30 liters commonly use flow rates up to 3 SLPM during their process steps. Brooks Instrument pressure controllers are a perfect fit for these services, offering stable pressure control with no droop, boost or hysteresis, which are commonly experienced when using a mechanical pressure regulator.

Typical Bioreactor Process Using an Upstream Pressure Controller

Fundamentals of Radar Technology for Level Gauging

RADAR Level transmitter
courtesy of KROHNE

The term “radar” is generally understood to mean a method by means of which short electromagnetic waves are used to detect distant objects and determine their location and movement. The term RADAR is an acronym from “RAdio Detection And Ranging”.

A complete radar measuring system is comprised of a transmitter with antenna, a transmission path, the reflecting target, a further transmission path (usually identical with the first one), and a receiver with antenna. Two separate antennas may be used, but often just one is used for both transmitting and receiving the radar signal.

Measuring the level of liquids or solids in vessels is a frequent requirement in industry. RADAR level measurement is the use of a radar signal is emitted via an antenna, reflected from the surface of the product and the echo received again after a time interval “t”.

The document below, courtesy of KROHNE, is an excellent technical reference for a strong understanding of RADAR level measurement.

Fundamentals of Radar Technology for Level Gauging from Instrument Specialties, Inc.

LCD Display for SOR Industrial Pressure Transmitter

SOR 800 Series

The SOR 800 Series pressure transmitters has a welded stainless steel sensor that eliminates the need for an o-ring and is extraordinarily reliable, accurate and immune from hydrogen and other contaminant based influences that originate from the process. This sensor is then embedded within a rugged but compact cast stainless steel electronics housing that contains circuitry choices of 4-20 mA or low-power 1-5 VDC output signals. Select models offer additional outputs. The “IN” option is provided with a 5-digit backlit loop powered LCD display enclosed in an explosion proof housing with terminal block connections inside.

See the video blow to learn more on the operation of the 800 Series optional LCD display.

Tying Together Brooks Mass Flow Controllers and LabVIEW™ Process Control Software

Brooks Instrument and LabVIEW™

Brooks Instrument manufactures very high quality mass flow controllers. LabVIEW™ develops and licenses integrated software for building measurement and control systems used in laboratory, university, and pilot manufacturing plants. There are many situations where Brooks MFCs and LabVIEW™ software provide excellent measurement and control of mass flow. Below are the most common and available ways to allow communication between Brooks MFCs and LabVIEW™ process control software.

Analog Signal Interface

In many situations LabVIEW™ software users also use analog to digital
I/O cards. With analog input cards, users can run their mass flow controllers utilizing a standard 0-5 volt or 4-20 mA analog signaling via LabVIEW™. This is a time-tested, traditional approach and is recommended for applications without the availability of digital control systems.

RS485 Digital Interface

Brooks Instrument mass flow devices configured with RS485 communications (must have the ‘S’ communications option) provide RS485 digital communications via a 15-pin D connector. The RS485 digital signal is passed directly to a computer running LabVIEW™ through a serial RS485 converter. Brooks models GF40, GF80 and SLA Series mass flow controllers are available with the ‘S’ communications option.

Its valuable to note that there is also a free set of VI file for use with LabVIEW from Brooks. These can be loaded directly into the LabVIEW™ application and provide the basics required to create a LabVIEW control interface using the S-Protocol digital command structure. The VI files are available for download from the Brooks Instrument website.

Another communications alternative is using Brook’s Smart DDE (Dynamic Data Exchange) software 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. While not a complete turnkey option, it greatly reduces the amount of code required to communicate between LabVIEW and the mass flow controller.

DeviceNet Digital Signal Interface

Brooks models GF40, GF80 and SLA, configured for DeviceNet digital communications, can also be controlled via the LabVIEW™ application provided a National Instruments DeviceNet interface card, associated drivers, and software are used. These additional items support the development of application interfaces using LabVIEW™ software for Windows and LabVIEW™ Real-Time.

According to 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.

It is always best to discuss your application with an authorized applications expert. For more information on mass flow controllers with analog or digital communications contact:

Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
phone 407.324.7800
fax 407.324.1104

www.isisales.com

Protecting Water and Wastewater Treatment Plants from Surges and Lightning Strikes

Reprinted with permission from DEHN

Water treatment plant are susceptible to lightning strikes.

Well heads and central processing plants found in water production and wastewater processing sites are susceptible to lightning and surge events. It is important to protect them as these events can range from disruptive at the least to damaging at the worst for your system.

As a company or utility involved in water production or wastewater treatment systems, you have invested a lot of time and money into making sure these systems run efficiently – and for good reason, because many of these systems have a large population depending on them for consistent service. Besides this population base, health and safety risks could occur if the systems are not running properly.

Furthermore, many of these systems depend on sensitive electronic equipment. The combination of

the intricacies of the systems and the importance of them means that an efficient lightning and surge protection system should be installed in the facility.

Protect against surges and strikes

The lightning and protection systems for water protection and wastewater treatment systems should be incorporated into the site’s construction, and feature an intermeshed earthing or grounding system. Ideally, these grounding systems should be designed by the engineering firm or department creating the design. Along with this grounding system, strategically placed and appropriately designed and installed surge arresters should be added to ensure the best defense against lightning and surge events.

Lightning and surge protection
by DEHN

To learn more about lightning strikes and their effect on industrial facilities, follow this link.

Or contact:
Instrument Specialties Inc.
3885 St. Johns Parkway
Sanford, FL 32771
Phone 407.324.7800

www.isisales.com

Fike Rupture Disc Sizing Bulletin

Fike rupture disc.

The objective of this bulletin is to provide detailed guidance for sizing rupture discs using standard methodologies found in ASME Section VIII Div. 1, API RP520, and Crane TP-410. To assist in the sizing process, contact Instrument Specialties at 407.324.7800 for help.

Overpressure Allowance

When sizing pressure relief devices, the Code defines the maximum pressure that may build up in the pressure vessel while the device is relieving. This pressure varies depending on the application of the device. The following table defines the various overpressure allowances.

Rupture Disc Sizing Methodologies

There are 3 basic methodologies for sizing rupture disc devices:

1. Coefficient of Discharge Method (KD) — The KD is the coefficient of discharge that is applied to the theoretical flow rate to arrive at a rated flow rate for simple systems.
2. Resistance to Flow Method (KR) — The KR represents the velocity head loss due to the rupture disc device. This head loss is included in the overall system loss calculations to determine the size of the relief system.
3. Combination Capacity Method — When a rupture disc device is installed in combination with a pressure relief valve, the valve capacity is derated by a default value of 0.9 or a tested value for the disc/valve combination. See technical bulletin TB8101 for specific application requirements when using rupture disc devices in combination with PRVs.

Access the entire bulletin below:

Fike Rupture Disc Sizing Bulletin from Instrument Specialties, Inc.

Smart Control for Steam Boiler Water Level

Maintaining proper water level in a boiler is necessary for safe and efficient operation. Historically, boiler level measurement and control were accomplished with mechanical means. Today, sensor technology, electronics, and software bring improved accuracy and a host of other useful features to the water level control system.

Clark-Reliance, a globally recognized leader in level indication and control, separation and filtration for steam systems, has developed a smart boiler level indication system to enhance boiler operation. The video included below provides an illustrative overview of the system, how it works and the benefits it will bring to a new or retrofit installation.

Share your combustion and steam challenges with experienced specialists, and combine your site and project knowledge with their expertise to deliver an effective solution.