Understanding Instrument Valves

Gauge Root Valve, a type of
instrument valve
Courtesy Mac-Weld

Process measurement and control employs a wide array of gauges and instruments that may be permanently or temporarily connected to a piping system. Providing controlled isolation and connection of these instruments is the function of what are generically referred to as "instrument valves" or "gauge valves". These valves are generally small, with connection sizes ranging from 1/8" to 1", though there are specialty variants outside this range. The predominant valve type is a needle valve, but ball valves and some other types are also used. Certain attributes of particular applications may weight a selection decision toward a valve type. Widely used throughout the process industries, instrument valves are often designed to accommodate pressures as high as 6000 PSI and are intended for service with gaseous or liquid service.

When selecting an instrument valve, consider construction materials that are compatible with the process media. Additionally, operating temperature and pressure of the process must be well within the limits of the valve.

Instrument needle valves provide reliable function to throttle, regulate and isolate gaseous and aggressive non-viscous liquid services. Product offerings range from simple two-way isolation valves to multiport gauge root valves providing multifunction capability to isolate, calibrate and vent gauge, pressure switches and static instrument applications. Ball valves in this class do not provide the throttling accuracy of a needle valve, but may provide some advantage with the use of certain media. The ball valve design, with its full size port, enables easier cleaning and a lessened potential for clogging.

There are three basic configurations of instrument valves. The simplest is the isolation valve with a single inlet and outlet. It provides for selection of exposure or isolation of a connected gauge or other device to the operating process piping or vessel. Maintenance or replacement of the connected device can be effected without opening the contained process to the surrounding environment.

Schematic representation of isolation valve

A second variant of instrument valves performs the function of an isolation valve, but has an added port on the outlet side (the side where a gauge or instrument would be connected). The added function of the port is to provide connection access for service, calibration, sampling, purging, or a host of other tasks, all of which can be completed while the process remains in operation.

Schematic representation of block and bleed valve

The third form of instrument valve is a multi-port valve with a single inlet and three outlets. It is often called a "gauge root valve" and serves a number of purposes with its multiple outlet connections. Sometimes two of the ports will be plugged and the instrument or gauge connected to the port providing the most convenient or functional orientation of the connected gauge or the valve handle. This valve can also enable a wide variety of applications through connection of additional instruments, gauges, valves, or other equipment.

Schematic representation of gauge root valve

Share your process measurement and control instrumentation and gauge challenges with application experts and benefit from their expertise.

Accurate Measurement of Very Low Flow Rates Is Key to Compressed Air System Energy Savings

The Flexus G704 CA is specially configured for
measuring flow in compressed air systems
Courtesy Flexim

Operators of plants where compressed air is utilized as an energy source are well aware of the cost associated with continuous delivery of this useful medium. Large or multiple compressors consume considerable amounts of electric power maintaining system pressure and flow requirements. With extensive piping and countless fittings, there are many potential points of leakage. Scheduling of various production operations can vary the demand for compressed air significantly. Getting control of your compressed air system and reducing operating cost is a noble goal. One of the primary tools needed to manage energy costs will be accurate and reliable flow measurement equipment. Here are some characteristics of flow measurement instrumentation that should prove advantageous:

• Non-invasive measurement from the outer pipe wall that does not add potential leak sources or pressure drop.
• Availability in fixed or portable configuration.
• Highly accurate, with paired temperature compensated traceable calibrated transducers
• Installed without disturbance to piping.
• Bidirectional measurement
• Rugged instrument design suitable for any kind of industrial environment

Portable version of specialized ultrasonic flow
measurement instrument for compressed air

Ultrasonic flow measurement technology can provide all of these characteristics, providing

information that enables the operator to make fact based decisions about system design, management, and maintenance. Learn more about how ultrasonic flow meters specifically configured for compressed air system application can help you start reducing your operating cost and developing a higher level of control over your compressed air system. Share your process challenges with a product specialist and work together to build the best solution.

Flexim Flow Measurement for HVAC and Production Sector from MSJacobs-Cali

Accurate Thermal Metering Using Non-Invasive Technology For Building HVAC Energy Management

Ultrasonic flowmeter specially configured for
thermal energy metering
Courtesy Flexim

The modern business climate has, for some now, been spooling up demand for accountability and, even more so, efficiency. Whether you think of efficiency as "doing more with less" or just avoiding the waste of financial, human, or natural resources the end result is the same and calls for similar prerequisites.

We live in a society of buildings, each with a mapped out function. Most buildings are predominantly occupied by people, bringing a requirement to maintain temperature, relative humidity, and air quality at levels of suitable comfort for human occupants. The energy consumption involved with providing that level of comfort stands as a bold line item in the operating expense ledger for any building. That is where accountability and efficiency come in. It is in the building stakeholders' interest to have knowledge regarding rates and quantity of thermal energy usage, as well as efficiency measures of delivered output per unit of input energy.

HVAC (Heating, Ventilation, Air Conditioning) primarily is an endeavor that generates and moves thermal energy throughout an enclosed space. Commercially available technology now allows a building operator to accurately measure that movement of thermal energy throughout a system or building. The process is generally called BTU metering and has a number of justifiable benefits.

• Real time equipment performance measurement.
• Sub metering can indicate specific areas of consumption.
• Ability to directly bill multiple tenants in a single building for their thermal energy usage.
• Monitor and balance energy flows.

BTU metering essentially involves inlet and outlet temperature measurement of heat transfer liquids, along with their flow rate. While the principle is simple, the intricacies of the measurement methods and equipment accuracy can have a substantial impact on the accuracy, and thus the benefit, of the measurement data. Additionally, adding more instrumentation to an already complex system can create an additional on-going maintenance and calibration burden to retain the necessary levels of accuracy and function. Success at gaining the benefit of the performance data while minimizing the additional maintenance burden due to the instrumentation should be the goal.

One solution calls for the use of clamp on ultrasonic flow meters to measure liquid flow, coupled with temperature measurement in a single unit that will perform necessary calculations and provide output data in useful engineering units. An overarching benefit of the clamp on meter is its non-invasive nature, allowing its retrofit to in-place systems with no disturbance to existing piping. Here are some other characteristics of a highly effective BTU measurement unit:

• No wear mechanism as part of the flow measurement unit
• Traceable accuracy of flow and temperature measurements
• Simple installation in new or retrofit applications without disruption to system operation
• Reliable and maintenance free operation
• Accurate measurement from near zero flow rate to maximum system flow
• Stable sensing with no zero drift
• Communications protocol to match building energy management system
• Large storage cache for data, in case of communication failure
• Common output signals, 4-20 ma or other, usable with selected ancillary equipment

Selecting the right equipment or instrumentation is the most important step along the path of adding measurement capability to increase efficiency. Without a solid stream of reliable data, useful decisions become difficult. Contact a product application specialist and share your requirements and goals. Combining your process and system knowledge with their product application expertise will produce a good outcome.

Flexim Flow Measurement for HVAC and Production Sector from MSJacobs-Cali

Selecting Single-ended vs. Differential Voltage Measurement for Process Measurement - Part 2 of 2

Selecting the proper signal conditioning equipment
is essential to maintaining process operation

This second part of a two part series of white papers provides discussion of the differences in function of differential and single-ended voltage measurement for industrial process measurement and control. Part One focused primarily on single-ended voltage measurement, how it differs from differential, and in what application context it can be best applied. This white paper, provided below, delves into differential voltage measurement and how it may be advantageous, even necessary, in a range of application scenarios.

The papers are produced by Acromag, Inc., a globally recognized manufacturer of signal conditioning equipment. Information about Acromag's extensive product offering is available from M.S. Jacobs & Associates, as well as technical details and application assistance.

Single-Ended vs. Differential Voltage Measurement - Part 2 of 2 from MSJacobs-Cali

Selecting Single-ended vs. Differential Voltage Measurement for Process Measurement - Part 1 of 2

Acromag manufactures an extensive array
of signal conditioning modules

Process control requires process measurement. The industry provides a enormous array of measuring devices for almost every conceivable process parameter. Selecting the right signal conditioner that will convert a current process state into a signal to be transmitted to and utilized by a controller can be challenging. One area of confusion centers around whether to use differential or single-ended voltage measurement.

Acromag, Inc., a globally recognized manufacturer of signal conditioning equipment for industrial process measurement and control, has provided a white paper that helps sort out reasons behind a beneficial selection of single-ended or differential voltage measurement devices. Explanation of how each functions and tips on selection criteria for an application are also provided. The technicality of the language is at a level that is comprehensible to most, but retains that exciting engineering edge for the purists among us. The first part of two (Part Two), provided below, focuses mostly on single-ended measurement. Part two covers differential.

Top flight assistance with your process measurement and control application challenges is available from M.S. Jacobs & Associates.

Single-Ended vs. Differential Voltage Measurement Part 1 of 2 from MSJacobs-Cali

Get To Know MS Jacobs & Associates for Industrial Process Control Instruments and Equipment

MS Jacobs serves the electric power generation industry,
as well as chemical, oil and gas, water and wastewater

M.S. Jacobs and Associates has been a leading manufacturer's representative and distributor of industrial instrumentation and controls since 1945.  Expanding from its original focus on the steel industry, MS Jacobs services and supplies products in all major industrial markets, including power generation, chemical processing, pulp and paper, oil and gas production, water and wastewater treatment, and nuclear power generation.

The company's longevity and dedication to the industrial market has resulted in a broad offering of superior quality products for flow, level, pressure, and temperature measurement, as well as filtration products and valves. Everyone at MS Jacobs takes pride in the company's ability to solve tough applications and provide exceptional customer service with a team of trained outside sales engineers and inside customer service representatives.

MS Jacobs' Pittsburgh service center provides instrument calibration and repair for MSJ's complete line of products, as well as those of other manufacturers. The company carries factory authorization for repair of numerous manufacturers' industrial process instrumentation products. The service center also provides custom assembly of instruments and other gear to meet customer requirements. Completed assemblies are tested and certified prior to shipment.

Reach out to MS Jacobs & Associates for the products and services that move your process instrumentation and control projects toward a successful completion.

MS Jacobs Line Card & Product Offering from MSJacobs-Cali

Non-Invasive Measurement of Extremely Low Flow Rates

Industrial process measurement and control operations present a continuous stream of challenges to designers, engineers, operators, and equipment manufacturers. The innumerable combinations of environmental, safety, financial, and other concerns have lead to a wide variety of instruments, equipment, and techniques for meeting specific process requirements. A critical element of many industrial processes is the measurement of liquid flow. Matching the best available flow measurement technology or product to an application calls for through knowledge of the process, the medium being measured, and the strengths and limitations of a proposed measurement device. The most current product and application information is available from specialists in flow measurement.

The video illustrates how a special adaptation of ultrasonic flow measurement technology is utilized to measure extremely low flow rates. Specific product information is also included, showing the advantages and specific application ranges of this specialty product from Flexim Americas.

Non-Invasive Measurement of Extremely Low Liquid Flow Rates from MSJacobs-Cali