Wednesday, August 15, 2018

Detonation Flame Arresters

Detonation Flame Arrester
Detonation Flame Arrester (Groth Corporation)
Detonation flame arresters are designed to prevent flame propagation in gas piping systems which contain flammable gas/vapor mixtures. It operates by removing heat from the flame as it attempts to travel through narrow passages with heat-conductive walls. The arrester will stop a high velocity flame by absorbing heat away from the flame head, which lowers the burning gas/air mixture below its auto-ignition temperature, and creating an atmosphere where the flame cannot be sustained. The arrester must prevent flame passage under certain specified conditions while permitting free flow of gas/vapor through the system. The channels or passages in the flame arrester are designed to very efficiently conduct heat outward, but still allow the gasses to flow. Thus it protects vulnerable equipment or components of the system from damage due to explosive pressures caused by gas/vapor ignition in another part of the system. The detonation flame arrester must be used under only those operating conditions for which it was designed and tested.

The flame arresters consist of two main components, the arrester bases and the flame element housing assembly. The bases serve as the connecting interface to the piping system. The housing retains and supports the flame element. Both components are essential in stopping the passage of the flame.

The flame element is comprised of small parallel passageways aligned so that an approaching flame front is slowed down and then quenched before it can propagate to the protected side of the device.

The bases must also withstand the detonation pressures while conveying the burning vapors and flame front to the element. Depending on the design of the system in which it is used, the arrester bases can include optional ports for thermocouples or pressure monitoring devices. These devices can activate warning or shutdown systems if abnormal conditions are detected. Both bases may be equipped with large diameter inspection/clean-out ports for in-line maintenance of the element, or element removal may be required for inspection/maintenance.

Flame arresters are used in many industries including chemical, refining, petrochemical, pulp and paper, oil exploration and production, pharmaceutical, sewage treatment, landfills, power generation, and bulk liquids transportation.

Please always consult with a properly qualified applications specialist prior to specifying, purchasing, or applying flame arresting devices.

Monday, July 23, 2018

Basics of Magnetic Flowmeters

Magnetic flow meter
Magnetic flowmeter
(Azbil)
Crucial aspects of process control include the ability to accurately determine qualities and quantities of materials. In terms of appraising and working with fluids (such as liquids, steam, and gases) the flowmeter is a staple tool, with the simple goal of expressing the delivery of a subject fluid in a quantified manner. Measurement of media flow velocity can be used, along with other conditions, to determine volumetric or mass flow. The magnetic flowmeter, also called a magmeter, is one of several technologies used to measure fluid flow.

In general, magnetic flowmeters are sturdy, reliable devices able to withstand hazardous environments while returning precise measurements to operators of a wide variety of processes. The magnetic flowmeter has no moving parts. The operational principle of the device is powered by Faraday's Law, a fundamental scientific understanding which states that a voltage will be induced across any conductor moving at a right angle through a magnetic field, with the voltage being proportional to the velocity of the conductor. The principle allows for an inherently hard-to-measure quality of a substance to be expressed via the magmeter. In a magmeter application, the meter produces the magnetic field referred to in Faraday's Law. The conductor is the fluid. The actual measurement of a magnetic flowmeter is the induced voltage corresponding to fluid velocity. This can be used to determine volumetric flow and mass flow when combined with other measurements.

The magnetic flowmeter technology is not impacted by temperature, pressure, or density of the subject fluid. It is however, necessary to fill the entire cross section of the pipe in order to derive useful volumetric flow measurements. Faraday's Law relies on conductivity, so the fluid being measured has to be electrically conductive. Many hydrocarbons are not sufficiently conductive for a flow measurement using this method, nor are gases.

Magmeters apply Faraday's law by using two charged magnetic coils; fluid passes through the magnetic field produced by the coils. A precise measurement of the voltage generated in the fluid will be proportional to fluid velocity. The relationship between voltage and flow is theoretically a linear expression, yet some outside factors may present barriers and complications in the interaction of the instrument with the subject fluid. These complications include a higher amount of voltage in the liquid being processed, and coupling issues between the signal circuit, power source, and/or connective leads of both an inductive and capacitive nature.

In addition to salient factors such as price, accuracy, ease of use, and the size-scale of the flowmeter in relation to the fluid system, there are multiple reasons why magmeters are the unit of choice for certain applications. They are resistant to corrosion, and can provide accurate measurement of dirty fluids ' making them suitable for wastewater measurement. As mentioned, there are no moving parts in a magmeter, keeping maintenance to a minimum. Power requirements are also low. Instruments are available in a wide range of configurations, sizes, and construction materials to accommodate various process installation requirements.

As with all process measurement instruments, proper selection, configuration, and installation are the real keys to a successful project. Share your flow measurement challenges of all types with a process measurement specialist, combining your process knowledge with their product application expertise to develop an effective solution.

Tuesday, July 17, 2018

Industrial Ball Valve Basics

Specialized ball valve
Specialized ball valve (PBM)
A ball valve is a rotational motion valve that uses a ball-shaped disk to stop or start fluid flow. The ball, performs the same function as the disk in the globe valve. When the valve handle is turned to open the valve, the ball rotates to a point where the hole through the ball is in line with the valve body inlet and outlet. When the valve is shut, the ball is rotated so that the hole is perpendicular to the flow openings of the valve body and the flow is stopped.

Most ball valve actuators are of the quick-acting type, which require a 90° turn of the valve handle to operate the valve. Other ball valve actuators are planetary gear-operated. This type of gearing allows the use of a relatively small handwheel and operating force to operate a fairly large valve.

MOGAS’s SC-3PC isolation valve
MOGAS’s SC-3PC isolation ball valve in closed position.
Some ball valves have been developed with a spherical surface coated plug that is off to one side in the open position and rotates into the flow passage until it blocks the flow path completely. Seating is accomplished by the eccentric movement of the plug. The valve requires no lubrication and can be used for throttling service.

Advantages

MOGAS’s SC-3PC isolation valve
MOGAS’s SC-3PC isolation ball valve in open position.
A ball valve is generally the least expensive of any valve configuration and has low maintenance costs. In addition to quick, quarter turn on-off operation, ball valves are compact, require no lubrication, and give tight sealing with low torque.

Disadvantages 

Conventional ball valves have relatively poor throttling characteristics. In a throttling position, the partially exposed seat rapidly erodes because of the impingement of high velocity flow. There are exceptions though, and ball valves can be used as control valves when modification to characterize the flow port are taken.

Port Patterns

Ball valves are available in the venturi, reduced, and full port pattern. The full port pattern has a ball with a bore equal to the inside diameter of the pipe.

Valve Materials 

Balls are usually metallic in metallic bodies with trim (seats) produced from elastomeric (elastic materials resembling rubber) materials. Plastic construction is also available.

The resilient seats for ball valves are made from various elastomeric material. The most common seat materials are teflon (TFE), filled TFE, Nylon, Buna-N, Neoprene, and combinations of these materials. Because of the elastomeric materials, these valves cannot be used at elevated temperatures. Care must be used in the selection of the seat material to ensure that it is compatible with the materials being handled by the valve.

Ball Valve Stem Design 

The stem in a ball valve is not fastened to the ball. It normally has a rectangular portion at the ball end which fits into a slot cut into the ball. The enlargement permits rotation of the ball as the stem is turned.

Ball Valve Bonnet Design 

A bonnet cap fastens to the body, which holds the stem assembly and ball in place. Adjustment of the bonnet cap permits compression of the packing, which supplies the stem seal. Packing for ball valve stems is usually in the configuration of die-formed packing rings normally of TFE, TFE-filled, or TFE-impregnated material. Some ball valve stems are sealed by means of O-rings rather than packing.

Ball Valve Position 

Some ball valves are equipped with stops that permit only 90° rotation. Others do not have stops and may be rotated 360°. With or without stops, a 90° rotation is all that is required for closing or opening a ball valve.

The handle indicates valve ball position. When the handle lies along the axis of the valve, the valve is open. When the handle lies 90° across the axis of the valve, the valve is closed. Some ball valve stems have a groove cut in the top face of the stem that shows the flowpath through the ball. Observation of the groove position indicates the position of the port through the ball. This feature is particularly advantageous on multiport ball valves.


For more information about any style industrial valve, contact CTi Controltech at 925-208-4250 or visit http://www.cti-ct.com.

Tuesday, July 3, 2018

Saturday, June 30, 2018

MOGAS iRSVP Power Industry Valve Designation and Markings

MOGAS iRSVP Series
MOGAS iRSVP vent
dran valve.
The MOGAS iRSVP Series is a family of isolation valves used for vents and drains in power applications. The iRSVP valve designed to handle high temperatures, high pressures, high cycling, thermal shock and abrasive media found in the power industry.

Applications for the MOGAS iRSVP
  • Boiler drains
  • Feedwater drains
  • Steam drum vents
  • Isolation valve for bypass lines
  • Economizer header drains
The following video is a tutorial on how to understand the iRSPV valve markings and designation system.

CTi Controltech
https://cti-ct.com
925-208-4250

Sunday, June 24, 2018

Convenient Rupture Disc Selection Form from Continental Disc Corporation

CDC rupture disc
CDC rupture disc.
Continental Disc Corporation is a leading manufacturer of rupture disc (bursting disc) devices for a variety of process industries, including chemical, petrochemical, petroleum refining, pharmaceutical, food and beverage, aerospace, industrial gases, transportation, and other markets worldwide.

They have a very convenient online form to assist in replacement of an existing rupture disc, or to specify a new installation. The form can be found by following this link. The form gives you the option to print it from its online page, or to email the form to Continental Disc sales department for a quotation.

In 2017, CTi Controltech was appointed the exclusive Continental Disc and Groth Equipment representative in Northern California and Nevada.

Friday, June 15, 2018

Pneumatic Damper Drives Superior to Electric Drives on Boiler Dampers

Pneumatic Damper drives
Pneumatic Damper Drives (Rotork)
In flue gas and combustion air applications, rapid response is critical for optimal efficiency, safety, and equipment longevity. Pneumatic vane damper drives don't have gears or motor windings that slow down response or introduce slop. In power plants boiler applications, Rotork Type K damper drives continue to provide a better solution for critical damper applications over electric drives.

Electric Drive
Old Electric Drive
Balanced-draft power generation boilers can experience very serious equipment failures if low pressure conditions exist inside the combustion chamber. Transients in boiler pressure can cause combustion complications leading to irregular heating of steam tubes, and in extreme situations, negative boiler pressure can collapse boiler walls and buckstays. There is a possibility for catastrophic failures (ruined boiler tubes, destroyed  refractory, boiler structural damage) leading to long shutdowns, lost production, and expensive re-construction. Pneumatic damper drives are excellent alternatives to electric drives in these applications because of speed, accuracy, and reliability.

Understanding the catastrophic possibilites, it is extremely important to provide consistent internal operating pressure environment for efficient and manageable combustion. ID (induced draft) fans on combustion boilers play a critical role in maintaining reliable boiler pressure. In turn, the ID fan inlet damper control system that regulates fan induced airflow and pressure need to be accurate, responsive, and reliable to assist in keeping boiler combustion chamber pressure fluctuations in check. Pneumatic vane drives react to signal changes and produce movement instantaneously and repeatably.
Pneumatic drive
New Pneumatic Drive

Rotork Type K PM Series Pedestal-Mount Damper Drives have proven themselves time and time again as the best choice for these applications. Pneumatic vane drives deliver high torque at tested speeds of less than 3 seconds for a full 90-degree stroke. They offer drop-in-place retrofit to the existing damper drive footprint, plus smart positioner technology. The Type K Drives perform quickly and smoothly at full boiler pressure and damper load, and as required, fail to the fully closed position.

The data collected after years of maintenance-free operation, in thousands of successful installations world-wide, is compelling. Pneumatic drives are superior to electric drives on boiler dampers.

Always discuss your damper drive application with an experienced applications engineer for best selection, optimal performance, and maximum safety.