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Limitorque Fluid Power Systems is a group of modular scotch yoke fluid power actuators designed to deliver maximum torque with the lowest possible displacement and overall size. These heavy-duty, fluid-powered valve actuators and control systems are design primarily for the oil and gas industry. The group is categorized into three major sub-groups:
Gas Powered Actuators - The Limitorque LDG direct gas actuator is designed to operate on high pressure pneumatic supply, including pipeline gases, nitrogen and any other equivalent high pressure source.
Hydraulic Actuators - LHS and LHH are Limitorque’s range of hydraulic, quarter-turn, scotch yoke actuators. Designed to meet or exceed the most current and stringent safety and reliability standards for application in the oil and gas industry LHS and LHH are suitable for on/off and modulating control of all quarter-turn valves.
Pneumatic Actuators - Limitorque’s LPS and LPC are pneumatic quarter turn scotch yoke actuators, featuring a robust design suitable for heavy duty services, and among the longest design lifespans and maintenance intervals in the industry.
Designers and manufacturers of industrial boilers are focused on meeting regulatory and safety requirements when developing highly efficient burner management systems (BMS). BMS are responsible for startup, operation and shutdown of a burner boiler systems. BMS monitor temperature, pressure and flow and employs safety shutoffs to shut down the burner boiler if an unsafe condition occurs.
The following white paper describes safety standards for boilers and burners relating to pressure switches and controls.
Veris Accelabar installed on vaporized liquid natural gas line.
Application
A liquid natural gas plant in the Midwest needed to measure gas flow to heaters that vaporize LNG to gaseous natural gas for use during peak periods in the winter season. The company stores LNG in two 12,000,000-gallon tanks and uses gas-fired heaters to vaporize it as required to meet customer demand. For most of the year demand is low (1,000 SCFH); however, during the coldest winter months gas consumption jumps to 60,000 standard cubic feet per hour (SCFH) in a 3” sch 40 line at 80 psig/70° F.
Problem
The plant must account for the gas usage over the entire range as it is part of the operating cost during LNG vaporization, as well as when it is used for plant heating. The customer could not find one meter to accommodate the entire range accurately. The plant had attempted to measure the flow rate with a Roots turbine meter sized for the maximum flow rate, but could not get accurate flow readings at the low end of the measurement range, making it impossible to determine actual usage during the off-peak periods. In addition to accuracy limitations, turbine meters have moving parts that wear and require expensive maintenance. The customer’s operating cost was estimated and charged against the bottom line. In addition, as you can see from the photo, there was no straight run available which hindered a conventional meter’s ability to perform accurately.
Accelabar
Solution
A Model AF 3” 150-H-M Accelabar was installed immediately downstream of a pipe reduction, control valve and pressure regulator. The Accelabar had two Foxboro IDP50 high accuracy DP transmitters directly mounted to the top of the Accelabar sensor. Stacked outputs were required to accommodate the wide turndown in DP of 308.2” w.c. at max and 0.08” w.c. at min.
Results
The Accelabar performed as advertised with ±0.75% accuracy over the entire range of 1,000 to 60,000 SCFH—a flow turndown of 60:1. Because the Accelabar and transmitters have no moving parts to wear or seize, maintenance is minimal. The LNG supplier has found that the flow metering system is user friendly and easy to operate, especially since DP flow measurement is one of the most easily understood of any flow measurement technology available. To the LNG provider, this translates into improved material accountability and lower operating costs to increase profitability.
The electromagnetic signal converter IMT30A is a used for measuring volumetric flow in various kinds of applications that can be found in the water industry and food and beverage processing. The IMT30A can be used together with Foxboro flow sensors 8400A, 8500A, 9500A, 9600A and 9700A with outputs representing measured values for flow, mass and conductivity.
Industries
Water & Wastewater
Food & Beverage
Heating, Ventilation & Air Conditioning (HVAC)
Agriculture
Steel
Applications
Water and wastewater treatment Water distribution network Irrigation installation
Limitorque Fluid Power Systems (LFPS) is the Flowserve Limitorque division that builds fluid power actuators, specifically pneumatic, gas, and hydraulic scotch yoke design cylinder valve actuators. These are used on larger, higher torque requirement valves primarily applied in the oil and gas industries.
GAS POWERED ACTUATORS
The Limitorque LDG direct gas actuator is designed to operate on high pressure pneumatic supply, including pipeline gases, nitrogen and any other equivalent high pressure source. Based on Limitorque’s high efficiency scotch-yoke modules, the self-contained system includes both the gas powered actuation unit and the high pressure gas control circuit. This makes it a robust and efficient way of providing reliable pipeline valve automation, even when no external motive power supplies are present. Limitorque’s advanced design criteria together with the full pressure rated controls allow higher torque output within a smaller dimensional envelope, thus reducing gas use and exhaust, and limiting pipeline product waste and environmental impact.
HYDRAULIC ACTUATORS
LHS and LHH are Limitorque’s range of hydraulic, quarter-turn, scotch yoke actuators. Designed to meet or exceed the most current and stringent safety and reliability standards for application in the oil and gas industry LHS and LHH are suitable for on/off and modulating control of all quarter-turn valves. Limitorque scotch yoke actuators deliver reliable torque ranges up to 300 kNm (221 268 ft-lb) in a low displacement, compact dimensional envelope with a maximum allowable working pressure (MAWP) of 207 barg (3000 psig) for the LHS series and 345 barg (5000 psig) for the LHH series.
PNEUMATIC ACTUATORS
Limitorque’s LPS and LPC are pneumatic quarter turn scotch yoke actuators, featuring a robust design suitable for heavy duty services, and among the longest design lifespans and maintenance intervals in the industry. Limitorque’s high torque LPS (up to 500000 Nm / 369,000 ft-lbs) and compact LPC (up to 5500 Nm / 4056 ft-lb) are the actuators of choice for effective on/off, modulating and control applications of quarter-turn valves in all general and protective services, in the most severe environments.
Wet steam is a costly problem across many industries. It causes product quality issues with batch rejection, wet packs and wet loads in sterilizers. Wet culinary steam can make food grade quality of product impossible. Carbon dioxide in a system with wet steam creates carbonic acid that damages pipes. A slug of water causes water hammering, which is destructive and can be deadly. Wet steam causes many flowmeters to be inaccurate, so that if you buy steam from a third party, you may be paying for water rather than steam. Water abrades like sand in a steam pipe and will erode pipes, elbows, valves and other components. Wet steam reduces heat transfer. Wet steam can damage turbines. And wet steam causes thermal stress as condensate cools down.
In fact, steam quality typically refers to the amount of water in the steam, which is also known as dryness fraction. Saturated steam is a mixture of steam and water. The water is often in the form of un-vaporized micro droplets. Dryness fraction is a ratio. The mass of the steam to the mass of the biphasic mixture of water and steam. Part of the difficulty in measuring the steam dryness fraction is that steam systems are dynamic. The steams is moving through the components and conditions change second-by-second. Within this complex system there are many things that contribute to water in the steam. For example, the bursting bubbles from the surface of the boiling water expels small droplets into the flow of steam. Or if there is a sudden increase in demand for steam that reduces pressure above the water, lowering the boiling point and increasing the violence of bubbling. This is sometimes called priming or carryover. Other forms of carryover include water in the system, because the water level in the boiler is too high. Or high concentrations of impurities in the boiler water that reduce the surface tension and so increase the agitation of the water surface. Impurities can also cause the formation of a stable foam above the water surface. This foam causes slugs of water to be intermittently discharged from the boiler along with the steam. Even poor insulation in pipes and valves leads to water in the steam as heat is lost and steam condenses. A steam trap might fail closed, particularly at the bottom of a separator, increasing the amount of condensate in the pipes. The design of steam pipe work and steam traps may be inadequate to handle condensate, or a steam separator may be defective.
Armstrong Steam QM-1
Any of these things individually or in combination can cause a problem with dryness fraction. Monitoring the dryness fraction of steam has long been a manual process, time-consuming, inconsistent, unreliable, and presents inherent safety and accuracy risks. Control of your steam quality depends on having consistent, accurate, timely information, and that's where the ArmstrongSteam QM-1 comes in.
The Armstrong steam quality monitor steam QM1 provides you with data logging and remote monitoring capabilities. The Steam QM-1 monitors and measures dryness fraction and alerts you of steam quality problems. The video below explains how.
With monitoring by the Steam QM-1 you can:
Manage process quality when injecting steam
Ensure foodgrade quality of steam when producing culinary steam
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