CTi is a Northern California based rep/engineering firm focused on providing integrated solutions for; valves, actuators, and controls. In addition we have expertise in the area of combustion & burner management controls and related components.
CTi maintains a California General Engineering Contractors License # 951993. Headquartered in San Ramon, CA, reach us at 925-208-4250 or CTi-CT.com
The introduction of this new electric valve actuator brings the advanced functionality and asset management capabilities of intelligent technology to the direct-drive operation of part-turn valves.
Valve maintenance requirements can be identified and anticipated, eliminating unplanned interruptions to the process or over-cautious planned maintenance outages. The actuator's powerful datalogger provides comprehensive data capture for planned maintenance and troubleshooting. Data includes valve torque profiles, operational start profiles, vibration and temperature trend logs and an event log. Specific asset management information includes running time, average torque and number of starts. Service or maintenance alarms are selectable from configurable menus including open and close torque levels, total starts and vibration levels.
An intelligent control valve system, the Flowserve StarPac can stand alone or be integrated into a system, and is available for a variety of applications including oil and gas, chemical, paper, mining, industrial gases and power generation.
Advantages for using this type of device are the following: Process Diagnostics – Evaluation of process equipment is possible with the StarPac intelligent control system. By generating an initial signature of the process and then identifying a standard process signature, a pump, compressor, heat exchanger, reactor, etc., can be discovered to be defective and in need of servicing. Process diagnostics can be per- formed with a personal computer or DCS connected to the unit via its serial data port.
Logging / Tuner Operation – The StarPac will take a 'snapshot' of process conditions at user-specified intervals (1 to 9999 seconds) and store them in its memory for later retrieval to aid in diagnosing process upsets. The personal computer operator interface will trend process variable, set point, and stem position to aid in tuning the control loop. This data is in a form that can be read by loop auto-tuning software to calculate the optimum PID constants.
Process Transmitters – The StarPac has sensors in the valve body to measure process conditions including upstream and downstream pressure, temperature, and flow. Flow is indicated both as the current value and a totalized amount. For gases, flow is reported in mass units, such as pounds per hour (since gas flow is always compensated for changes in pressure and temperature). Other sensors measure stem position and pressures in the top and bottom chambers of the cylinder actuator. All of these values are available over the serial link to a computer or DCS.
Connections to Operator Interface – The StarPac can be connected to an operator interface (personal computer, DCS console or hand station and recorder) through its analog, discrete and digital channels. The StarPac houses two analog inputs and one analog output. Up to six analog outputs are available using an external converter module. Two discrete inputs and two discrete outputs are also available at the StarPac. The user can define how these channels will be defined. Normally one analog input is a command signal, one discrete input sets the control mode, and the discrete outputs signal alarm conditions. The digital channel can be connected to computers and most DCSs through gateways or Modbus ports. All of the process and configuration information is available through the digital channels.
High Interchangeability – Since the Valtek Mark OneTM, MaxFloTM and ShearStreamTM control valves are the basis of the StarPac system, most valve parts are interchangeable with other Valtek valves, reducing parts inventory.
Local Display – Eight variables (P1, P2, temperature, gas flow, liquid flow, total flow, setpoint, stem position) can be displayed on a liquid crystal display in the electronics module. Each variable can be set to display continuously, or the StarPac can be set to scroll through the chosen variables at ten-second intervals. An error indicator will show if the StarPac system should fail any internal diagnostic or if the process is out of range.
Multiple Failure Modes – StarPac technology allows multiple failure modes to be set, including: power, air supply, command signal, or process failure. This results in greater reliability and consistency of the process during emergency shutdowns, protecting the process and people.
Valve Diagnostics – A maintenance feedback package allows StarPac intelligent systems to display the condition of the valve packing, seat, actuator, and O-rings with only a brief process interruption without removing the valve from the line. PC software displays the actuator or process signature for analysis. Optional valve diagnostic software can determine specific valve failures.
User Friendly Software – When the user is not connecting the StarPac unit to a DCS, StarTalk software can configure, operate, and diagnose the StarPac unit through a personal computer. The software has a graphical user interface, allowing most users to operate their StarPac systems with minimal training.
Environmental Considerations – Locating pressure and temperature sensors in the valve body eliminates several process connections. All pressure sensors have at least two seals to reduce the possibility of leaks to the atmosphere. Remote-mounted pressure sensors can be fitted with isola- tion and/or purge valves to aid maintenance of the sensors.
Check out this video for further explanation:
CTi Controltech
22 Beta Ct.
San Ramon, CA 94583
Phone: 925-208-4250
Fax: 925-208-4251
Email: contactus@cti-ct.com
www.cti-ct.com
High performance rotary control valve (courtesy of Valtek)
High performance control valves, providing a bubble-tight seal along with a wide range of sizes and pressure classifications are used in many industrial applications. Examples are:
Fire protection
Gas service
Condenser cooling
Gas scrubbing
Mine dewatering
Pipeline service,
Cooling water
This type of control valve should achieve bi-directional, bubble-tight shutoff while maintaining low breakout torque - at both high and low pressure drops.
Often, these valves are available in carbon steel, 316 stainless steel and other alloys and is available in ANSI Classes 150 through 2500, sizes 2 through 30-inch.
Rotary disc, high performance control valves offer a double offset designed into the disc that lifts the disc out of the seat immediately upon actuation. This avoids wear on the seat and disc, reducing leakage and parts replacement. It also improves throttling by eliminating friction.
For more information, review the tech manual below:
Here is a quick overview of one of the most popular, and universally specified, electric actuators - the ROTORK IQ Series.
The IQ electric actuator features include ROTORK's unique double-sealed enclosure, ‘non-intrusive' infra-red commissioning, data-logging, predictive maintenance, Bluetooth® communications interface and absolute encoder.
The IQ functionality and reliability is available for valves of virtually every size and description, including multi-turn (rotary), quarter-turn, isolating and modulating, with watertight and hazardous area approvals to all internationally recognized standards.
Selective Catalytic Reduction
(courtesy of Wikipedia)
Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as NOx with the aid of a catalyst into diatomic nitrogen, N2, and water, H2O. A gaseous reductant is added to a stream of flue or exhaust gas and is absorbed on to a catalyst.
Commercial selective catalytic reduction systems are typically found on large utility boilers, industrial boilers, and municipal solid waste boilers and have been shown to reduce NOx by 70-95%. More recent applications include diesel engines, such as those found on large ships, diesel locomotives, gas turbines, and even automobiles.
CTi Controltech manufactures custom SCR systems and would be glad to discuss your requirements.
New 50,000 PPH Boiler, Central Valley
New SCR, ammonia injection grid, and ammonia delivery skid
Haldor Topsoe Catalyst
New Ultra Low Nox Burner (RMB technology)
New Biogas blending system
New PLC based combustion control system
New Fireye Burner Management (BMS)
Designed to operate at less than 6 PPM NOx
Retrofit 300,000 PPH Boiler, Bay Area
New SCR, ammonia injection grid, and ammonia delivery skid
Here is a presentation made to the Pacific Northwest International Section of the Air & Waste Management Association outlining the advantages of PEMS (predictive emissions monitoring systems) over stack flow devices.
The presentation was made by the president of CMC Solutions, a leading supplier of PEMS or predictive emission monitoring systems.
A PEMS can be configured, delivered and installed in 30-45 days. Installation of a PEMS requires the installation of a single computer with the DAS/PEMS software installed and interfaced to the boiler control system. Typically a one day installation and start up process.
PEMS have lower startup costs, normally one day including DAS.
PEMS require less on site training. PEMS training is usually 1 to 1 1⁄2 days plus DAS training.
PEMS should require no on site emergency service. A direct modem to the system takes care of 99% of all service requirements.
PEMS do not require dual range analyzers.
PEMS do not require EPA protocol calibration gases, piping, wiring, gas regulators or software to operate the auto-calibration sequence.
PEMS require no air source.
PEMS have no ongoing preventative maintenance requirements.
Williams & Davis Boilers of Hutchins, Texas announced today the
engagement of CTi Controltech of San Ramon, CA, as the exclusive
representative for Williams & Davis Boilers in Northern California
and Northwestern Nevada.
CTi Controltech will provide sales,
service, and support for Williams & Davis steam boilers, hot water
boilers, electric boilers, feed water systems, deaerators, blowdown
separators, and economizers. According to Jennifer Carradine, Manager at
Williams and Davis, "CTi was selected because of their professionalism,
knowledge, years of experience and courtesy to their customers. These
are attributes and values we at Williams and Davis hold dear." Carradine
later added, "We are confident that CTi will provide W&D customers
and partners with the same high level of service and support they have
grown to expect."
The Williams and Davis boiler product line adds
to the already strong combustion equipment and boiler offering at CTi.
"WIlliams and Davis Boilers is a great addition to the CTi product
line" said George Constas, President of CTi Controltech. "They are known
for their innovation, quality and customer service. We see it as a
perfect fit."
This video provides a look inside the Valtek Mark One Control Valve and highlights its major components and unique design.
When reviewing industrial control valves, the Valtek Mark One globe control valve offers stands out because of it's excellent performance
controlling liquids and gases, while at the same time allowing fast, easy and
inexpensive maintenance.
The unique spring-cylinder actuated Mark One valve provides stiffness which contributes to the valve's high positioning accuracy, controlled high
speed, repeatability, and response.
A data center chiller is a cooling system used to remove the heat generated by computer hardware and storage devices, and transfers that heat to another place where it can be used for some other process. Chillers are used in the data centers heating, ventilating and air-conditioning (HVAC) systems. Large scale HVAC chillers are used to provide accurate and reliable cooling. These chillers work around the clock to keep ambient temperatures optimized for data center operation. Because of the considerable heat generated by so many servers operating in such close proximity to one another, accurate and reliable temperature and humidity control is critical. If there is a failure, building temperatures would rise quickly and possibly ruin equipment and lose data.
A main component of the cooling system is the chilled water 3-way control valve used to throttle the chilled water to the building’s heat exchangers. It is essential that these control valves control accurately and perform reliably. Also, and in the event of a power failure, they must be programmable to move to a predetermined valve position.
I many data center HVAC applications, electric actuators are the preferred means to actuate the control valves. Their reliability, tightness of control, and failure-mode programmability are key reasons why chiller OEMs and data center building engineers choose electric actuators.
In a Power Station burning both low-sulphur fuel oil and natural gas, an electric control valve actuator was installed on an outdoor fuel oil control valve application. The existing 6” ball valves which utilized a pneumatic I/P positioner and spring diaphragm pneumatic actuator wasn’t performing well. A decision was made to use a ROTORK CVA electric control valve actuator because it provides extremely precise control-valve operation with repeatability and resolution performance at less than 0.1% of full scale.
Because the valve operates outdoors, and modulates frequently to control the flow of fuel oil held in storage tanks to the fuel oil pumps, its a difficult application to get precise control. The built-in Bluetooth communications makes it easy to set up, calibrate and monitor performance.
The valve failure mode is also very important, in both loses-of-signal and loss-of-power. The specified ROTORK Actuators use a charged super capacitor and the built-in programming of the actuator control to assure proper “fail-to” in any event.
A HIPPS (high-integrity pressure protection system) is a category of "instrumented system" designed to prevent an over-pressurization condition at a process plant.
For oil, gas and chemical producers, loss of containment is a critical matter. Over-pressure on a tank, vessel or pipeline can potentially cause explosive, flammable, toxic or hazardous chemicals to be released causing possible loss of life or adverse effects on the environment. Loss of containment can also have huge negative effects on the plants bottom line.
HIPPS will shut off the source of the high pressure before the design pressure of the system is exceeded, as opposed to a relief system which will open an alternative outlet for the fluids in the system once a set pressure is exceeded. A relief system attempts to remove any excess inflow of fluids for safe disposal, where a HIPPS is designed to stop the inflow of excess fluids and containing them in the system. Conventional relief systems are increasingly frowned upon because they typically vent, flare or discharge hazardous or toxic fluids in to the environment.
HIPPS valves are used as the final part of an instrumented system intended to prevent an unacceptably high pressure occurring in downstream equipment. They are always arranged to fail closed and spring/hydraulic actuators are usually the only practical alternative for operation.
Igniters provide proven ignition energy to immediately light-off the burner. They are permanently installed. Igniters are classified as follows by NFPA:
Class 3 special: High energy igniter (HEI) capable of directly igniting the main burner fuel. Generally consists of a spark-rod, and power pack to deliver the high voltage pulse train, and required cabling. Operation time of igniter is no longer than required to light-off burner, within maximum allowed trial-for-ignition time.
Class 3: Low capacity igniter applied particularly to gas and oil burners. Ignites the fuel input to the burner under prescribed light-off conditions. The range of class 3 igniters generally do not exceed 4 percent of full load burner input. Operation time of igniter is not longer than required to light-off the burner, within the maximum allowed trial-for-ignition time.
Class 2: Medium capability igniter applied particularly to gas and oil burners to ignite the fuel input to the burner under prescribed light-off conditions. The range of class 2 igniters generally is 4 to 10 percent of full-load burner input. Class 2 igniters may remain in operation to support ignition under low-load or adverse operating conditions. Class 2 igniters cannot be used to extend main burner turn-down range.
Class 1: High capacity igniter used to ignite the fuel input through the burner. Supports ignition under any burner light-off or operating conditions. Its location and capacity provide sufficient ignition energy at its associated burner to raise any credible combination of burner inputs of both fuel and air above the minimum ignition temperature. Tests are to be performed with this ignition system in service to verify that the igniter furnished meets the requirement of this class as specified in its design. Class 1 igniters can be used to extend the main burner’s turndown, where they are in service and flame if proved.
Combustion (or burning) is a rapid combination of oxygen with fuel, resulting in a release of heat. Air (the oxygen source) is about 21% oxygen and 78% nitrogen by volume. Most fuels contain carbon, hydrogen, and sometimes sulphur. A simplification of combustion could be listed in the following three processes.
These products of combustion are chemical compounds. They consist of molecules, combined in fixed proportions. Heat given off in any combustion process is excess energy which the molecules must release.
Stoichiometric combustion results when no fuel or air goes unused during the combustion process. Combustion with too much (excess) air is said to be lean or oxidizing. The excess air or oxygen plays no part in the combustion process. In fact, it reduces efficiency. Visually, excess air produces a short and clear flame. Combustion with too much fuel is called rich or reducing, producing incomplete combustion. This flame appears long and some- times smoky. The oxygen supply for combustion generally comes from ambient air.
Burners are simple devices that convert fossil fuels into heat energy. In order to achieve safe and reliable operation, each burner must be equipped with a monitoring and control system. The complexity of a safe and reliable system is relative to the complexity of the process at hand. This system can be as simple as a single burner using a single fuel, to a complex multi-burner environment where many burners fire into a common combustion chamber where multiple fuels are burned simultaneously. Conditions affecting the complexity of control systems is not necessarily dependent upon large burner input, but IS dependent upon the following conditions:
Type of process.
Type of burner.
Multi- or single burner environment.
Multi or single fuel operation.
Safety hazard of fuel burner.
Local codes and standards.
Redundancy and reliability factors.
Continuous or intermittent burner operation.
Recent technological advances require knowledge of applications and systems and should be applied only by qualified technicians. Standards are set by local authorities and must be understood and properly operated in order to assure that safety requirements are met.
Flow characteristics, the relationship between flow coefficient and valve stroke, has been a subject of considerable debate. Many valve types, such as butterfly, eccentric disk and ball valves, have an inherent characteristic which cannot be changed (except with characterizable positioner cams). Flow characteristics of globe valves can be determined by the shape of the plug head.
Control Valve Flow
Characteristics
The three most common types of flow characteristics are quick opening, equal percentage and linear. The adjacent figure shows the ideal characteristic curve for each. These characteristics can be approximated by contouring the plug. However, inasmuch as there are body effects and other uncontrollable factors, plus the need for maximizing the flow capacity for a particular valve, the real curves often deviate considerably from these ideals. When a constant pressure drop is maintained across the valve, the characteristic of the valve alone controls the flow; this characteristic is referred to as the “inherent flow characteristic.” “Installed characteristics” include both the valve and pipeline effects. The difference can best be understood by examining an entire system. Equal Percentage
Equal percentage is the characteristic most commonly used in process control. The change in flow per unit of valve stroke is directly proportional to the flow occurring just before the change is made. While the flow characteristic of the valve itself may be equal percentage, most control loops will produce an installed characteristic approaching linear when the overall system pressure drop is large relative to that across the valve. Linear
An inherently linear characteristic produces equal changes in flow per unit of valve stroke regardless of plug position. Linear plugs are used on those systems where the valve pressure drop is a major portion of the total system pressure drop.
Quick Open
Quick open plugs are used for on-off applications designed to produce maximum flow quickly.
This information provided courtesy of Flowserve Valtek. Further technical information can be found at this link.
This rotary ball control valve video (courtesy of MOGAS) provides an informative look at the flow conditions inside a valve designed with a tortuous flow path and specialized characterization.
The Flexstream rotary control valve uses a standard ball valve body with a very specialized ball. As the ball opens, the video shows the tortuous path. The design allows for volumetric expansion when controlling gas. Velocity, noise and cavitation are controlled by repeated 90 degree turns in the flow path. This design is excellent for applications that require wide range-ability.
When selecting an electric actuator for industrial valves, an understanding of the valve torque requirements, both at start of travel, and end of travel, is critical for proper operation and optimal service life. Additionally, the ability to accurately set, or limit, disk travel is required.
Many of today's industrial electric valve actuators provide easy setting or programming of travel and torque sensing.
This short video provides a brief visual understanding of the reasons why valve torque and travel limits are important.
Scotch yoke refers to a sliding linear mechanism that provides a reciprocating motion. One of the most common uses for scotch yokes are pneumatic valve actuators.
Scotch yoke valve actuators are designed to provide higher torque output for larger industrial valves. They typically have large pistons and air cylinders that provide the linear force required to open and close large quarter turn valves (ball, butterfly, plug).
Scotch yoke pneumatic actuators installed
in sea terminal
(courtesy of Rotork)
Scotch yoke actuators can be energized by either compressed gases, or hydraulic fluids. Here are some images of scotch yoke actuators in use:
Large spring return scotch yoke actuator
(courtesy of Rotork)
Choosing an improperly applied sized or improperly sized control valve can have serious consequences on operation, productivity and most important, safety. Here is a quick checkist of basics that need to be considered:
Not an isolation valve:
Control valves are not intended for isolating a process and should not be used as such. They are not intended to provide a bubble tight shutoff.
Choose the correct materials of construction:
The valve body, seat and wetted materials must be compatible with the process being controlled. Take into consideration pressure ratings and operating temperatures along with the material compatibility prior to valve selection.
.GIF "SCR")
