03232017Thu
Last updateThu, 23 Mar 2017 7pm

i

Valve Selection in Pulp and Paper Operations

Valve Selection in Pulp and Paper Operations

Over the centuries, the pulp and paper i...

How to Improve Control Valve Performance with Positioners

How to Improve Control Valve Performance with Positioners

As the final control element in most pro...

VMA Technical Event: Engineering Valves in the Extreme

VMA Technical Event: Engineering Valves in the Extreme

While much the 2017 VMA Technical Semina...

FEL: The Preferred Phase for Valve Technical Definition

FEL: The Preferred Phase for Valve Technical Definition

A typical oil and gas capital project cy...

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

GE Oil & Gas Expands with New Sub Saharan Africa Facility

Thursday, 23 March 2017  |  Chris Guy

GE Oil & Gas opened a new facility in Takoradi Port, Ghana, expanding its global footprint and supporting local investment. The facility, which wi...

Readmore

Loading...

Industry Headlines

GE Oil & Gas Expands with New Sub Saharan Africa Facility

-1 DAYS AGO

GE Oil & Gas opened a new facility in Takoradi Port, Ghana, expanding its global footprint and supporting local investment. The facility, which will be the primary service center for deep-water offshore projects in Ghana, has a 1,600 square meter indoor test area with capability for testing thre...

Readmore

Metso Launches Digital Program to Accelerate Growth

1 DAY AGO

Metso has set up a Digital Program to accelerate the company’s digital capabilities, which are required to succeed in the future of minerals processing and flow control. Metso's ambition is to become one of the digital leaders in the industries it serves. This means for example turning custome...

Readmore

Shell Looking to Lower Cost of Offshore Projects

2 HOURS AGO

“With oil prices hovering around $50 a barrel or less, and a rising amount of renewable energy chipping away at market share, Shell is going lean on its deepwater projects to make sure it can eke out a profit from all of its operations,” writes ChemInfo .

For example, Shell is attempting to ...

Readmore

Report Says PA Can Support Four More Ethane Crackers

3 HOURS AGO

A new report from IHS Markit, commissioned by the state of Pennsylvania, forecasts $2.7 to 3.7 billion in investments in natural gas liquid (NGL) assets as well as the opportunity to attract additional cracker plants, and petrochemical and plastics manufacturing. IHS Markit believes the Marcellus an...

Readmore

Consumer Sentiment Reaches Highest Level Since 2000

2 DAYS AGO

The overall level of consumer sentiment remained quite favorable in early March due to renewed strength in current economic conditions as well as the extraordinary influence of partisanship on economic prospects. The current economic conditions component reached its highest level since 2000, largely...

Readmore

U.S. Manufacturing Output Rose 0.5% in February

3 DAYS AGO

Industrial production was unchanged in February following a 0.1% decrease in January. In February, manufacturing output moved up 0.5% for its sixth consecutive monthly increase . Led by advances of more than 1% for nonmetallic mineral products, fabricated metal products, and machinery, the production ...

Readmore

A Case for Mechanical Temperature Control

vmwnt12_beyond_valves_fig1Instrument, mechanical or project engineers may see a multitude of temperature applications cross their desks. Their immediate reaction might be to employ a temperature control loop. But could a mechanical, self-operated temperature regulator be a better solution for the valve application?

When approaching a temperature control application, the engineer usually considers:

  • The degree of accuracy needed
  • Whether the application requires feedback (Are limit switches/output signals used?)
  • Whether the application needs to be controlled through a DCS, PLC or other type of controller
  • The budget for the application.

The answer to whether a mechanical temperature regulator might be a cost-effective and reliable solution for the application depends on those considerations.

In almost any process facility, a variety of temperature control applications can be found. As with any controlled variable, both the accuracy and criticality of those applications can vary widely. Often, non-critical temperature applications become instrumented control loops even when a self-operated or mechanical regulator could provide the desired accuracy along with a substantial cost savings.


WHAT’S CONSIDERED

vmwnt12_beyond_valves_fig1Figure 1. Temperature regulatorA typical temperature control loop ­(Figure 1) requires:

  • a temperature sensor
  • wiring and conduit
  • connection to a controlling device
  • a control valve (and sometimes a positioner and/or I/P converter, and an air-filter regulator)
  • plant air

A self-contained temperature regulator requires no power, no air supply or other expensive compo­nents to operate. Representative costs based on a 1-inch line size would be:

  • Temperature transmitter: $300-1,000
  • Temperature controller: $400-1,000
  • Control valve and actuator: $1,500-3,000
  • I/P converter: $200-350
  • Air set regulator: $100-150
  • Positioner: $500-2,000
  • Control loop total: $3,000-7,500
  • Temperature regulator: $500-2,500

Although designs may vary from manufacturer to manufacturer, most temperature regulators operate on the same principle. A premeasured amount of “fill” is drawn into the thermal system filling the upper diaphragm chamber, the capillary tube and most of the bulb. As the controlled temperature increases, the fill in the sensing bulb begins to vaporize and creates pressure on the sealed system. This pressure drives the valve stem, closing direct-acting valves or opening reverse-acting valves. By using different fill fluids, many different temperature control ranges can be offered for both cooling and heating applications—temperature ranges are readily available from -20° F (-29° C) to 500° F (260° C).

Applications for which these devices might be ideal include tank farms, large heat exchangers, heat exchangers with slow temperature changes, area heating/cooling (warehouse/maintenance shops) and steam tracing.

  • Latest Post

  • Popular

  • Links

  • Events

Advertisement

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association