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.

Thursday, May 31, 2018

Increased cycle count improves operational efficiency in slurry ore mining operations

slurry pipeline
Slurry pipeline.
Challenge
Long distance slurry pipelines for moving mineral concentrates over various elevations and long distances is often more economical than trucking or rail due to topography constraints and environmental concerns. To capitalize on these investments, the pipe sizes are maximized. Therefore, large-bore dependable valves are vital to the success of the slurry pipelines.

Three months after the main choke and choke loop press letdown stations were commissioned at a large copper-gold-molybdenum mining operation, ongoing repairs were required for all eight competitor valves. Valves in this position were expected to perform for at least 180 cycles without repair. These failures and leakage problems were caused by the valves’ integral seat design, which form a gap between the ball and seat allowing particles to enter the sealing area in the reverse pressure. This problem cost this customer an average of $800,000 to $1M per year in maintenance repairs.

Solution
MOGAS valve
After one year the
MOGAS valve performed 818
successful cycles—over four times the cycle
count required in this application.
Even with MOGAS’ 40-year history of successfully engineering large valves for the slurry transport market, MOGAS proposed to lease a test valve to be placed alongside a series of competitor valves.
In January 2013, a 36-inch, ASME 300 Class model CST-1 valve was installed in the first loop of the control station. In this model’s proven bi-directional seat design, the seat maintains 100% contact with the ball in both normal and reverse pressures. This prevents build-up behind the downstream seat and ensures evacuation of solids around upstream seat during cycling.


Results
Under the same process conditions,
the competitor’s valve underperformed and
required frequent maintenance due to erosion.
One year later during decommission, the MOGAS valve was inspected. It had performed 818 cycles; far more than the 180 cycle count required in this application. The MOGAS valve was then removed and installed outside the loop, in the main choke station replacing the competitor valve, where it further performed 215 cycles for the next two years.

After three years of continuous operation, the MOGAS valve had successfully performed 1033 cycles. On inspection, the ball and seat were in good repair, so only the gasket and packing box were replaced and the valve was put back in to service.

Advantages to installing a MOGAS valve:
  • No downtime due to increased cycle time and continuous operation 
  • No repair or maintenance of ball and seat
  • Increased cycle count and greater revenue
For more information, contact CTi Controltech by calling 925-208-4250 or visit https://cti-ct.com.

Reprinted with permission from MOGAS.

Wednesday, May 23, 2018

Welcome to CTi Controltech

Since 1976 CTi Controltech has represented the leading process control and combustion manufacturers.  These products, together with our engineering capabilities, give CTi customers high quality solutions to the most difficult industrial applications.

CTi is focused on the top quality manufacturers in process control, valves, instrumentation, and combustion. Over the past three decades CTi has continually added and upgraded the quality of companies it represents.

Our staff of engineers and technicians is well versed with all our products and are ready to help you with your most demanding applications.