08182017Fri
Last updateFri, 18 Aug 2017 1pm

i

Safety Relief Valve FAQs

Safety Relief Valve FAQs

Companies that repair, test, maintain or...

An Update on U.S. Valve-Related Standards

An Update on U.S. Valve-Related Standards

It takes much time and effort by many pe...

Diagnostics for Commissioning and Startup

Diagnostics for Commissioning and Startup

Many facilities have found value in perf...

Subscribe SUM17

FREE SUBSCRIPTION*

•  Print magazine
•  Digital magazine
•  VALVE eNews
Read the latest issue

*to qualified valve professionals in the U.S./Canada

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

Advertisement
i

Web Only

Safety Relief Valve FAQs

Safety Relief Valve FAQs

Monday, 14 August 2017  |  Lyndon Garrick

Companies that repair, test, maintain or supply valves routinely receive inquiries from end users about safety-relief valves. Here are a few questions...

Readmore

Loading...

Industry Headlines

Forum Energy Technologies Acquires Multilift

1 DAY AGO

Forum Energy Technologies, Inc. has acquired the stock of Multilift from Pelican Energy Partners, a Houston-based oilfield services focused private equity fund, and management. Based in Houston, Multilift manufactures the patented SandGuard and the Cyclone completion tools; products that extend the ...

Readmore

ValvTechnologies Names Teele Director of Global Quality Management

3 DAYS AGO

ValvTechnologies, Inc. has appointed Michael Teele director of global quality management. Based in Houston, Teele will be responsible for setting and maintaining global quality standards, systems and processes, as well as serving as a leadership champion of continuous improvement. With a deep technic...

Readmore

Executive Order to Speed Up Infrastructure Project Approval

1 DAY AGO

President Trump signed an executive order intended to roll back “rules regarding environmental reviews and restrictions on government-funded building projects in flood-prone areas as part of his proposal to spend $1 trillion to fix aging U.S. infrastructure,” Reuters reports .

“Trump's...

Readmore

DuPont and Dow Chemical Set Closing Date for Merger

2 DAYS AGO

DuPont and The Dow Chemical Company announced that all required regulatory approvals and clearances have been received, that all conditions to closing of their merger of equals have been satisfied, and that their merger of equals will close after the market closes on August 31, 2017.

“The compa...

Readmore

U.S. Factory Output Declined in July

7 HOURS AGO

Manufacturing output edged down 0.1% in July. The index for durables decreased 0.5%. Among durable manufacturing industries, with the indexes for primary metals and for furniture and related products each dropped more than 1%. The index for other manufacturing (publishing and logging) moved down 0.4%....

Readmore

Empire State Manufacturing Index Highest in Nearly Three Years

2 DAYS AGO

Business activity grew strongly in New York State, according to firms responding to the August 2017 Empire State Manufacturing Survey. The headline general business conditions index climbed fifteen points to 25.2, its highest level since September 2014. The new orders index rose seven points to 20.6 a...

Readmore

The Well-Functioning Steam Trap

vmwnt09 beyond valves 1Ultrasonic instruments are used to test a thermodynamic steam trapSteam traps are the most important link between the steam and condensate system. Malfunctioning steam traps can waste tremendous amounts of money. Here is an example: A single inverted bucket steam trap (with a one-eighth-inch orifice) blowing-thru in a 150 psi, where the steam cost is $11.00 per 1,000 lbs. of steam produced, will waste 62.49 lbs. of steam per hour and cost approximately $6,022 in fuel losses per year.

 

Steam Traps Defined

For those who are not familiar with the steam trap, it is an automatic valve that, when operating properly, opens to purge a steam system of condensate and closes with the presence of steam.

There are three types of steam traps:

  • Density operated, which includes the inverted-bucket (IB) and the float and thermostatic (FT) types
  • Thermostatic (TH), specifically, the balance-pressure thermostatic (BPT) type
  • Thermodynamic (TD), either the disc or impulse type

Trap Characteristics

vmwnt09 beyond valves 2An inverted bucket steam trapFloat and thermostatic traps consist of a ball float and a thermostatic bellows element. As condensate flows through the body, the float rises or falls, opening the valve according to the flow rate. The thermostatic element discharges air from the steam lines. They are good in heavy and light loads and on high and low pressure, but are not recommended where water-hammer is a possibility.

When these traps fail, they usually fail closed. However, the ball float may become damaged and sink down, failing in the open position. The thermostatic element may also fail and cause a fail-open condition.

Thermostatic traps have, as the main operating element, a metallic corrugated bellows that is filled with an alcohol mixture that has a boiling point lower than that of water. The bellows will contract when in contact with condensate and expand when steam is present. Should a heavy condensate load occur, such as in start-up, the bellows will remain in a contracted state, allowing condensate to flow continuously. As steam builds up, the bellows will close. Therefore, there will be moments when this trap will act as a “continuous flow” type while at other times it will act intermittently as it opens and closes to condensate and steam, or it may remain totally closed.

These traps adjust automatically to variations of steam pressure but may be damaged in the presence of water-hammer. They can fail open should the bellows become damaged or due to particulates in the valve hole that will prevent adequate closing. Sometimes the trap becomes plugged and will fail closed.

Inverted bucket traps have a “bucket” that rises or falls as steam and/or condensate enters the trap body. When steam is in the body, the bucket rises, closing a valve. As condensate enters, the bucket sinks down, opening a valve and allowing the condensate to drain.

Inverted bucket traps are ideally suited for water-hammer conditions but may be subject to freezing in low temperature climates if not insulated. When an inverted bucket trap fails, it fails open due to the bucket losing its prime and sinking, or from impurities in the system that may prevent the valve from closing.

  • 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