Sunday, February 28, 2016

Using Eductors for Non-Powered Tank Mixing

eductor for tank mixing
Eductor for tank mixing
(courtesy of Jacoby Tarbox)
An eductor is a pump that uses a fluid to perform the work of pumping another fluid (or solid). The fluid doing the work is termed the motive fluid, and the fluid being pumped is the suction fluid. The motive fluid employed can be liquid. gas or steam. The suction fluid can be liquid. gas or steam. Other names for eductors include jet pumps, ejectors, Venturi pumps, siphon pumps, steam siphons, and injector pumps. Eductors operate on basic principles of flow dynamics.

Eductors require no power, which means no moving parts. The design of the eductor creates pressure differential allowing fluid to flow naturally within the device - creating suction, mixing, and pushing the liquid throughout the tank.

In-line eductors are the next generation of jet pumps, ejectors, and Venturi pumps providing in-line mixing, pumping, or heating in various process lines. Eductors reduce costs as there are no moving parts and require no direct power.

The video below, while marketing oriented, does a great job at demonstrating how tank mixing is accomplished efficiently and thoroughly with an array of eductors by calculating tank size and volume along with material properties to develop a mixing profile.


For more information, contact:

Mead O'Brien
(800) 892-2769
www.meadobrien.com

Tuesday, February 23, 2016

Theory of Operation for MOVs (Motor Operated Valves)

Limitorque SMB MOV
Limitorque SMB MOV
This presentation, provided by the NRC, provides an introductory look at motor operated valves, with a focus on the manufacturer Limitorque. The document includes the theory of operation of MOVs, plus descriptions of valve types, such as gate, globe, ball, plug and butterfly.

This document also provides detailed descriptions of Limitorque SMB actuators and Limitorque SB actuators with full assembly and subassembly breakdown and illustrations.




Document provided by NRC.gov

Monday, February 15, 2016

Configuring a Foxboro PH10 Sensor Using the Foxboro 876PH Transmitter

pH Sensors and ORP Sensors
pH and ORP Sensor
(courtesy of Foxboro)
The PH10 DolpHin® Series pH Sensors and ORP10 DolpHin Series ORP Sensors are suitable for a wide range of pH and ORP measurement applications. They are designed for use with Foxboro® brand 875PH, 873PH, and 873DPX Analyzers, and 876PH Intelligent Transmitters and 870ITPH Transmitters. Some can also be used with 873APH Analyzers. When used with 875PH Analyzers or 876PH and 870ITPH Transmitters, they provide the additional capability of on-line diagnostics to signal the user if any of several common sensor faults occur.

The sensors are available with a choice of temperature compensation and cable termination. They are available with an internal pre-amplifer for use up to 150 m (500 ft) and with a Smart sensor for use up to 100 m (328 ft) from the analyzer or transmitter. The sensors can be mounted to the process in a number of ways. They have a 3/4-inch external NPT connection on both the electrode and cable end. The sensors can be inserted directly into the process line or tank or mounted through a variety of accessories including bushings, tees, flow chambers, and ball valves/insertion assemblies.The sensors are available in both analog and Smart versions.

These industry-leading sensors are already proven in countless installations including chemicals, pulp & paper, all kinds of industry and municipal water/wastewater treatment, metals/mining, and food and dairy applications worldwide.

The Foxboro® brand Model 876PH is a 2-wire loop powered intelligent transmitter that, when used with appropriate electrochemical sensors, provides measurement, local display, and transmission of pH, ORP (Oxidation-Reduction Potential), or ISE (Ion Selective Electrode) concentration. The transmitter outputs a HART digital signal and a 4 to 20 mA analog output. Versions are available for use with both analog and Smart (digital) sensors.

This video demonstrates how to correctly configure a Foxboro® PH10 sensor using the Foxboro® 876PH Transmitter.



Form ore information, contact:

Mead O'Brien
www.meadobrien.com
(800) 892-2769

Thursday, February 4, 2016

The Rack and Pinion Style Pneumatic Valve Actuator

Automax Actuator
Rack & Pinion Actuator
(courtesy of Flowserve Automax)
Three primary kinds of valve actuators are commonly used: pneumatic, hydraulic, and electric.

Pneumatic actuators can be further categorized as scotch yoke design, vane design, and the subject of this post - rack and pinion actuators.

Rack and pinion actuators provide a rotational movement designed to open and close quarter-turn valves such as ball, butterfly, or plug valves and also for operating industrial or commercial dampers.
internal of rack and pinion actuator

The rotational movement of a rack and pinion actuator is accomplished via linear motion and two gears. A circular gear, referred to a “pinion” engages the teeth of a linear gear “bar” referred to as the “rack”.

Pneumatic actuators use pistons that are attached to the rack. As air or spring power is applied the to pistons, the rack is “pushed” inward or “pulled” outward. This linear movement is transferred to the rotary pinion gear (in both directions) providing bi-directional rotation.

rack and pinion
Visual of rack and pinion
(courtesy of Wikipedia)
Rack and pinion actuators pistons can be pressurized with air, gas, or oil to provide the linear the movement that spins the pinion gear. To rotate the pinion gear in the opposite direction, the air, gas, or oil must be redirected to the other sides of the piston, or use coil springs as the energy source for rotation. Rack and pinion actuators using springs are referred to as "spring-return actuators". Actuators that rely on opposite side pressurization of the rack are referred to as "direct acting".

Most actuators are designed for 100-degree travel with clockwise and counterclockwise travel adjustment for open and closed positions. World standard ISO mounting pad are commonly available to provide ease and flexibility in direct valve installation.

NAMUR mounting dimensions on actuator pneumatic port connections and on actuator accessory holes and drive shaft are also common design features to make adding pilot valves and accessories more convenient.

actuated valve
Fully automated valve with rack
and pinion actuator, solenoid, and
limit switch.
Pneumatic pneumatic rack and pinion actuators are compact and save space. They are reliable, durable and provide a good life cycle. There are many brands of rack and pinion actuators on the market, all with subtle differences in piston seals, shaft seals, spring design and body designs.

For more information on any pneumatic or electric valve automation project, contact:

Mead O’Brien, Inc.
www.meadobrien.com
10800 Midwest Industrial Blvd
St. Louis, Missouri 63132
Phone (314) 423-5161
Toll Free (800) 874-9655
Fax (314) 423-5707
Email: meadstl@meadobrien.com

Wednesday, January 27, 2016

Pneumatic Instruments

pneumatic transmitters
Pneumatic transmitters
(courtesy of Foxboro)
Air pressure may be used as an alternative signaling medium to electricity. Imagine a pressure transmitter designed to output a variable air pressure according to its calibration rather than a variable electric current. Such a transmitter would have to be supplied with a source of constant-pressure compressed air instead of an electric voltage, and the resulting output signal would be conveyed to the indicator via tubing instead of wires:


The indicator in this case would be a special pressure gauge, calibrated to read in units of process pressure although actuated by the pressure of clean compressed air from the transmitter instead of directly by process fluid. The most common range of air pressure for industrial pneumatic instruments is 3 to 15 PSI. An output pressure of 3 PSI represents the low end of the process measurement scale and an output pressure of 15 PSI represents the high end of the measurement scale. Applied to the previous example of a transmitter calibrated to a range of 0 to 250 PSI, a lack of process pressure would result in the transmitter outputting a 3 PSI air signal and full process pressure would result in an air signal of 15 PSI. The face of this special “receiver” gauge would be labeled from 0 to 250 PSI, while the actual mechanism would operate on the 3 to 15 PSI range output by the transmitter. As with the 4-20 mA loop, the end-user need not know how the information gets transmitted from the process to the indicator. The 3-15 PSI signal medium is once again transparent to the operator.

Typically, a 3 PSI pressure value represents 0% of scale, a 15 PSI pressure value represents 100% of scale, and any pressure value in between 3 and 15 PSI represents a commensurate percentage in between 0% and 100%. The following table shows the corresponding current and percentage values for each 25% increment between 0% and 100%. Every instrument technician tasked with maintaining 3-15 PSI pneumatic instruments commits these values to memory, because they are referenced so often:

Using the Foxboro model 13A pneumatic differential pressure transmitter as an example, the video below highlights the major design elements of pneumatic transmitters, including an overview of "maximum working pressure" versus "maximum measurement range" pressure.

The Foxboro model 13A pneumatic d/p cell transmitters measure differential pressure and transmit a proportional pneumatic output signal.


The information above is attributed to Tony Kuphaldt and is licensed under the Creative Commons Attribution 3.0.

Wednesday, January 20, 2016

Mead O'Brien: Steam and Hot Water System Experts


Let Mead O’Brien help you create a sustainable Steam Trap Management Process!
  • Trained Survey Technicians 
  • Traps located and identified, tagged with SS tag #, and data logged with up to 27 fields of useful data per trap 
  • Executive summary, Failed trap report with steam & dollar losses, detailed Log sheets, and Recommendations are all provided in a professional report. 
  • Monitoring options presented for critical service applications 
  • Steam flow measurement design 
  • Heat recovery potential 
  • Training options in a live steam lab 
Realize the Savings Now!
  • Reduce steam & condensate losses 
  • Reduce loss of boiler chemicals 
  • Improve heat transfer performance 
  • Prevent coil and heat exchanger damage 
  • Minimize water hammer hazards 


Mead O’Brien and Armstrong, more than 85 years of Steam & Hot Water System Optimization

  • Steam Distribution
  • Process Heat Transfer and Control
  • Condensate Return
  • Heat Recovery Opportunities
  • Process, Ambient & Combustion Air
  • Steam Trap Surveys & Database Creation 
  • Humidification Assessment
  • Application issues
    • - Coil Freezing Issues
    • - Poor Heat Transfer & Steam Control - Water Hammer Issues
    • - High Backpressure
  • Steam & Condensate Measurements, Control & Monitoring

Learning Systems:

  • Armstrong University
  • Over 125 web-based courses 
  • Mead O’Brien Live Steam Lab
  • Content Tailored for Plant Need

Friday, January 15, 2016

Steam Trap Testing Guide for Energy Conservation

steam trap testing schedule
Annual steam trap testing schedule

Below is a steam trap testing guide (courtesy of Armstrong International) to maximize efficiency and conserve energy. This guide discusses:
  • Steam Trap Testing Procedure 
  • Tips On Listening 
  • Inverted Bucket 
  • Float & Thermostatic Trap 
  • Disc Trap 
  • Thermostatic Trap 
  • Sub-Cooling Trap 
  • Traps on Superheated Steam
CAUTION: Valves in steam lines should be opened or closed by authorized personnel only, following the correct procedure for specific system conditions. Always isolate steam trap from pressurized supply and return lines before opening for inspection or repair. Isolate strainer from pressurized system before opening to clean. Failure to follow correct procedures can result in system damage and possible bodily injury.