Pressure Regulating Valves

Pressure regulating valve, or pressure regulator.
One of many types.
Image courtesy Cash Valve

Pressure regulating valves (PRV) are common components of many processes and equipment. The function of a PRV is to maintain a desired outlet fluid pressure under varying conditions of supply pressure or outlet flow demand.

Many variants exist in the market, each specifically designed to address a range of process conditions or offset a performance characteristic deemed undesirable in another design. Each has a suitable place in the range of possible applications, with cost, size, construction material and complexity primary differences among the offerings.

In its simplest form, a pressure regulating valve (PRV) consists of a flow restricting element, a measuring element, and a setpoint element. Outlet pressure applies force to the measuring element, often a diaphragm. As the outlet pressure increases, the diaphragm will move the flow restricting element toward the closed position, reducing the flow from the inlet. The restricting element is commonly a plug, disk, or some other recognizable valve trim arrangement. The setpoint element, likely a spring, provides a counterbalancing force on the diaphragm. When the force applied to the diaphragm by the outlet pressure reaches equilibrium with the counterbalancing force applied by the spring, movement of the restricting element stops. In this way, outlet pressure is controlled without the need for electric power, sensors, transmitters, or even a process controller. The entire assembly is self-contained and requires little attention.

Selecting a PRV for an application requires coordinated consideration of process performance range, desired conditions, and valve attributes to produce a selection that will provide the desired service. A valve improperly selected for an application may perform poorly. Some of the items to be considered include:

• PRV Type
• Body size
• Construction
• Pressure Ratings
• Maximum Flow Rate
• Outlet Pressure Range
• Accuracy
• Inlet Pressure
• Orifice Diameter
• Response Speed
• Turn-Down Ratio

A PRV is not a safety device. An independent means must be provided to protect the system from excessive pressure. Product specialists are a good source of help in selecting a properly sized and configured valve for an application. Share your fluid process control challenges with a product application specialist. Leverage your own process knowledge and experience with their product application expertise to develop an effective solution.

Flow Measurement in Subsurface Pipes

Ultrasonic flow measurement, properly configured, can be the preferred solution for flow measurement in water and wastewater pipes, especially those in subsurface locations. Demands for increased monitoring of system flow at numerous points throughout a network or system create a need to install flow measurement instrumentation on existing pipes that are unlikely to have built-in accommodations for the needed sensors.

Ultrasonic flow measurement transducers are mounted on the exterior of existing piping and require no pipe cutting or service interuption to install. The rugged transducers are suitable for subsurface installation and provide long term uninterupted operation. Ultrasonic flow measurement functions over a wide range of flow, providing accurate data during normal, peak, and off-peak hours. The data derived from the measurements can also be used for leak detection. Data output from the instrument can be used locally or transferred by a number of methods to remote monitoring stations for system wide analysis.

The video provides some additional application advantages of ultrasonic flow measurement for subsurface pipe applications. Share your flow measurement challenges of all types with process measurement specialists. Leverage your own knowledge and experience with their product application expertise to develop effective solutions.

Auma Heavy Duty Electric Valve Actuators

Cutaway view of electric valve actuator.
Image courtesy Auma Actuators, Inc.

Electric actuators are used to enable remote control of industrial valves, allowing complex processes to be managed and controlled by remotely located control systems. Other means, including hydraulic and pneumatic, are used as  motive forces for valve actuators, but electric actuators bring a particular set of features that make them an advantageous choice for many applications.

Valve actuators are available in a wide range of variants to suit every application scenario. Auma, a globally recognized manufacturer of electric actuators, manufactures heavy duty actuators for demanding applications throughout every industry. Specializing in electric actuators, the company keeps their design and engineering efforts focused on a single product, its performance, reliability, and ruggedness.

• Part turn, linear and multi-turn operation
• Large selection of torque ranges
• Variable or fixed speed operation
• Controller options ranging from simple open-close to micro-positioning with logging of operating data or fieldbus interface
• Numerous gearbox options and mountings to accommodate any application
• Enclosures rated for a variety of installations, including underwater.

Learn more about the electric actuators from Auma. Share your valve and damper automation challenges with industrial application experts, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

Electric Actuators for Industrial Valve Automation from Classic Controls, Inc.

Fox Thermal Instruments Releases New Gas Flowmeter Targeted at Oil and Gas Operations

The FT4X thermal mass flow meter accommodates
inline, insertion, and retractor installations.
Image courtesy Fox Thermal Instruments, Inc.

Keeping up to date on the latest product information....

Fox Thermal Instruments, an acknowledged innovator in thermal mass flow technology and instruments, has released a flow meter targeted for gas flow measurement in the oil and gas industry. The FT4X delivers a long list of advanced and useful features for flare and waste gas monitoring, gas studies, royalty and allocation, and general gas flow research.

The instrument utilizes a constant temperature differential technology to measure gas or air mass flow, employing two precision RTD sensors. One temperature sensor follows the media temperature, while the other is heated by the instrument electronics to maintain a constant temperature differential between the two sensors. The amount of applied heat to maintain the differential is proportional to the mass flow rate. A linearized 4-20mA output signal is the final output of the transmitter.

The flow meter is available for inline or insertion installation, along with another variant that features retraction of the instrument from the line without flow interruption. Various probe lengths accommodate line sizes to 70 inches. Flow bodies, flow conditioners, and other accessories are available to customize the instrument assembly to fit each application.

There is a wealth of additional information provided in the brochure included below. Share your flow measurement challenges and requirements for process measurement specialists. Leverage your own knowledge and experience with their product application expertise to develop effective solutions.

Thermal Mass Flow Meter for Oil & Gas Applications from Classic Controls, Inc.