Consider Controlled Environment Room Air Flow

Air flow characteristics can determine how well a controlled
environment room or chamber performs for an application

Environmental chambers, whether of the reach-in or walk-in variety, all rely on the movement of air within their controlled space to attain performance specifications. Various manufacturers will employ differing strategies for chamber air movement, and the manner in which their designs disperse air flow throughout a chamber of any size can have an impact on the work or process held within the chamber.

This article is about controlled environment rooms, but much of what is included here is also applicable to smaller sized chambers.

The design of air flow in a controlled environment room can be impacted by a number of factors, some of which may be based on specific application requirements, and others that may be influenced by cost, production simplicity, or other factors unrelated to the performance goal of the equipment.

What aspects of controlled environment room air flow bear on performance?

• Velocity - In the common usage of the term when referring to air flow, the speed of the moving air. Depending upon the air moving equipment arrangement and any dispersion devices, such as perforated suspended ceilings or wall plenums, air velocity can vary throughout a chamber. Users should consider how their work may be impacted by air flow velocity. The storage of material in closed and sealed containers may be impervious to air velocity effects because the "product" within the container is not in contact with the moving air. Plants and insects, on the other hand, are an example of items that may be significantly or severely impacted by air velocity. Higher air velocity at a chamber location exposes that location to more air per unit of time. Desiccation is one possible concern that is exacerbated by increased air velocity. Higher velocity can also be beneficial, even necessary, for some applications. Rapid cooling or heating of materials placed within a chamber is enhanced by increased air movement across the material surface.
• Volume - The volumetric flow of air through a controlled space or chamber is needed to transfer heat to or from the space in order to maintain temperature control. Much of the air in a controlled environment room is recirculated, with cooling, heating, and in some cases moisture applied to condition the air in the room to the setpoint. The volume of air movement is loosely related to velocity, so increasing volume will result in an increase in velocity unless other design changes are made with respect to how the air is dispersed throughout the room. Higher volume, or turnover rate, contributes to better temperature uniformity in the room. As with velocity, there may be application specific requirements for low air movement. Keep in mind that low air movement creates challenges to the attainment of close temperature control and uniformity. 
• Pattern - The way in which air is distributed throughout the controlled environment room can impact system performance once materials are placed in the room or process work is commenced. Empty chambers generally perform well, regardless of the air flow pattern, because there is little in the way of a load on the system and no solid materials in place to block or redirect air flow. Consideration should be given to the way in which air is dispersed throughout the work area. Loading patterns for stored product or the placement of work in process should be accommodated by the air flow pattern.

Matching the right air flow characteristics to the work to be achieved in a controlled environment room will result in better overall performance, not just when empty chamber tests are conducted, but when real work is being accomplished.

Share your environmental chamber and controlled environment room requirements and challenges with application experts. The combination of your own experience and knowledge with their specialized technical expertise will yield an effective solution.

Monitoring Catalyst Presulfiding

Catalyst ‘presulfiding’ is a practice which reduces the extent of early catalyst deactivation on by preventing coking (carbon deposits). The procedure involves passing a gas stream containing H₂S over the catalyst or into the reaction feedstock.

In order to generate the H₂S which will interact with the catalyst, a sulfur carrying agent (e.g. dimethyl sulfide) is injected into the stream. Under high temperature and catalytic reaction, the agent decomposes and releases its sulfur component, forming H₂S. The H₂S reacts with the catalyst’s metallic surface to substitute sulfur atoms for oxygen atoms.

Read the document below to learn more about monitoring this process with the Applied Analytics OMA-300 H₂S Analyzer

Monitoring Catalyst Presulfiding Step from Ives Equipment

Ives Equipment Business Groups

Ives Equipment organizes its extensive product line into four distinct groups:

Ives Equipment and Controls, providing instrumentation and control products to the chemical, petro-chemical, refining, bulk storage, primary metals, pulp & paper, powergen, gas & oil distribution and OEM markets.

Pharmaceutical, Bio-pharm, and Sanitary, providing hygienic, ultra-pure and sanitary instruments, connectors, fittings, tubing and gaskets to the pharma, bio-pharm, food and beverage, life-science and labortory industries.

Analytical Instruments, used to analyze process material samples and record the data for quality, conformance and compliance.

Water and Wastewater Treatment, providing instruments, analyzers, valves and controls for the transfer, storage, analysis, treatment, and logging of municipal and industrial water treatment systems.

Definition: Industrial Valve Actuator

Pneumatic actuator on ball valve.
(Worcester)

Actuators are devices which supply the force and motion to open and close valves. They can be manually, pneumatically, hydraulically, or electrically operated. In common industrial usage, the term actuator generally refers to a device which employs a non-human power source and can respond to a controlling signal. Handles and wheels, technically manual actuators, are not usually referred to as actuators. They do not provide the automation component characteristic of powered units.

Electric actuator (Worcester)

The primary function of a valve actuator is to set and hold the valve position in response to a process control signal. Actuator operation is related to the valve on which it is installed, not the process regulated by the valve. Thus a general purpose actuator may be used across a broad range of applications.

In a control loop, the controller has an input signal parameter, registered from the process, and compares it to a desired setpoint parameter. The controller adjusts its output to eliminate the difference between the process setpoint and process measured condition. The output signal then drives some control element, in this case the actuator, so that the error between setpoint and actual conditions is reduced. The output signal from the controller serves as the input signal to the actuator, resulting in a repositioning of the valve trim to increase or decrease the fluid flow through the valve.

Electro-hydraulic actuator
(MIH Trident)

An actuator must provide sufficient force to open and close its companion valve. The size or power of the actuator must match the operating and torque requirements of the companion valve. After an evaluation is done for the specific application, it may be found that other things must be accommodated by the actuator, such as dynamic fluid properties of the process or the seating and unseating properties of the valve. It is important that each specific application be evaluated to develop a carefully matched valve and actuator for the process.

Hydraulic and electric actuators are readily available in multi-turn and quarter-turn configurations. Pneumatic actuators are generally one of two types applied to quarter-turn valves: scotch-yoke and rack and pinion. A third type of pneumatic actuator, the vane actuator, is also available.

For converting input power into torque, electric actuators use motors and gear boxes while pneumatic actuators use air cylinders. Depending on torque and force required by the valve, the motor horsepower, gearing, and size of pneumatic cylinder may change.

There are almost countless valve actuator variants available in the industrial marketplace. Many are tailored for very narrow application ranges, while others are more generally applied. Special designs can offer more complex operating characteristics. Ultimately, when applying actuators to any type of device, consultation with an application specialist is recommended to help establish and attain proper performance, safety and cost goals, as well as evaluation and matching of the proper actuator to the valve operation requirements. Share your fluid process control requirements with a specialist in valve automation, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Contact Ives Equipment for any valve actuator application. Visit http://www.ivesequipment.com or call (877) 768-1600.

Principles of Ultrasonic Flow in Industrial Clamp On Flow Meters

The video below demonstrate the principles applied to industrial clamp on flow meters using the SITRANS FS as an example.

The ultrasonic technology of the SITRANS clamp on flow meter provides highly accurate measurement of liquids and gases. With no pressure drop or energy loss, a wide turn-down ratio and no need to cut the pipe or stop the flow, installation is easy and maintenance is minimal.

For more information about ultrasonic flow meters, contact Ives Equipment at 877-768-1600 or visit http://www.ivesequipment.com.

Happy Fourth of July from Ives Equipment

"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. — That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, — That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."

THOMAS JEFFERSON, Declaration of Independence

Refinery Gas Analyses Using Compact Gas Chromatographs and Gas Detectors

The analysis of trace permanent gases has many different fields of application in the petrochemical industry. One of the most important is for controlling the manufacturing process and the product quality. For example, some contaminants as carbon monoxide and carbon dioxide tend to deteriorate the catalysts in the propylene and ethylene polymer grade production.

An instrument for monitoring trace impurities is then required. Many different GC techniques are available on the market. Most of the techniques use a combination of TCD, FID and methanizer for the trace analysis of H2-O2-N2-CH4-CO-CO2 in propylene and ethylene. More precisely, an FID and a methanizer are used to trace CH4-CO and CO2. A TCD with Hydrogen or Helium carrier gas is used to trace O2-N2 detection. Finally, a second TCD with Argon or Nitrogen carrier gas must be added to trace H2 detection. These solutions require complex GC solutions with multiple detectors and multiple gas sources for carrier, fuel and air. On top of that, an FPD must be added in some cases when the trace analysis of H2S is required.

Read the application note below for more information. Contact Ives Equipment at (877) 768-1600 or visit http://www.ivesequipment.com for a consultation.

Refinery Gas Analyses with Multidetek2 Compact Gas Chromatograph and Plasmadetek2 Gas Detector from Ives Equipment