Steam Trap selection Guide

A steam trap selection guide - Float & Thermostatic, Inverted Bucket, Bimetal Thermostatic, Impulse and Thermodynamic Disc steam traps:

There are three primary categories of steam traps:

• mechanical
• thermostatic
• thermodynamic

Popular traps in these categories includes the inverted bucket steam trap, the float steam trap, the thermostatic steam trap and the thermodynamic disc steam trap.Which one is preferred depends on the application.
A steam trap prime missions is to remove condensate and air preventing escape of live steam from the distribution system. The steam trap must adapt to the application. A disc thermodynamic steam trap should never be used together with a modulating heat exchanger - and a floating ball steam trap is overkill for draining steam pipes.
The table below can be used as a short guide for the selection of steam traps:

Type of Steam Trap	Operation				Normal Failure Mode
	No or little load	Light Load	Normal Load	Heavy Load
Float & Thermostatic	No Action	Usually continuous. May cycle.	Usually continuous. May cycle.	Continuous	Closed
Inverted Bucket	Small Dribble	May dribble	Intermittent	Continuous	Variable
Bimetal Thermostatic	No Action	Usually Dribble Action	May blast at high pressures	Continuous	Open
Impulse	Small Dribble	Usually continuous with blast at high loads	Usually continuous with blast at high loads	Continuous	Open
Thermodynamic Disc	No Action	Intermittent	Intermittent	Continuous	Open

Inverted Bucket Steam Trap

The inverted bucket is the most reliable steam trap operating principle known. The heart of its simple design is a unique leverage system that multiplies the force provided by the bucket to open the valve against pressure. Since the bucket is open at the bottom, it resists damage from water hammers, and wearing points are heavily reinforced for long life.

• intermittent operation - condensate drainage is continuous, discharge is intermittent
• small dribble at no load, intermittent at light and normal load, continuous at full load
• excellent energy conservation
• excellent resistance to wear
• excellent corrosion resistance
• excellent resistance to hydraulic shocks
• vents air and CO₂ at steam temperature
• poor ability to vent air at very low pressure
• fair ability to handle start up air loads
• excellent operation against back pressure
• good resistance to damage from freezing
• excellent ability to purge system
• excellent performance on very light loads
• immediate responsiveness to slugs of condensate
• excellent ability to handle dirt
• large comparative physical size
• fair ability to handle flash steam
• open at mechanical failure

Thermostatic Steam Traps

There are two basic designs for the thermostatic steam trap, a bimetallic and a balanced pressure design. Both designs use the difference in temperature between live steam and condensate or air to control the release of condensate and air from the steam line.
In an thermostatic bimetallic trap it is common that an oil filled element expands when heated to close a valve against a seat. It may be possible to adjust the discharge temperature of the trap - often between 60^oC and 100^oC.
This makes the thermostatic trap suited to get rid of large quantities of air and cold condensate at the start-up condition. On the other hand the thermostatic trap will have problems to adapt to the variations common in modulating heat exchangers.

• intermittent operation
• fair energy conservation
• fair resistance to wear
• good corrosion resistance
• poor resistance to hydraulic shocks (good for bimetal traps)
• do not vent air and CO₂ at steam temperature
• good ability to vent air at very low pressure
• excellent ability to handle start up air loads
• excellent operation against back pressure
• good resistance to damage from freezing
• good ability to purge system
• excellent performance on very light loads
• delayed responsiveness to slugs of condensate
• fair ability to handle dirt
• small comparative physical size
• poor ability to handle flash steam
• open or closed at mechanical failure depending of the construction

Float Steam Traps

In the float steam trap a valve is connected to a float in such a way that a valve opens when the float rises.
The float steam trap adapts very well to varying conditions as is the best choice for modulating heat exchangers, but the float steam trap is relatively expensive and not very robust against water hammers.

• continuous operation but may cycle at high pressures
• no action at no load, continuous at full load
• good energy conservation
• good resistance to wear
• good corrosion resistance
• poor resistance to hydraulic shocks
• do not vent air and CO₂ at steam temperature
• excellent ability to vent air at very low pressure
• excellent ability to handle start up air loads
• excellent operation against back pressure
• poor resistance to damage from freezing
• fair ability to purge system
• excellent performance on very light loads
• immediate responsiveness to slugs of condensate
• poor ability to handle dirt
• large comparative physical size
• poor ability to handle flash steam
• closed at mechanical failure

Thermodynamic Disc Steam Traps

The thermodynamic trap is an robust steam trap with simple operation. The trap operates by means of the dynamic effect of flash steam as it passes through the trap.

• intermittent operation
• poor energy conservation
• poor resistance to wear
• excellent corrosion resistance
• excellent resistance to hydraulic shocks
• do not vent air and CO₂ at steam temperature
• not recommended at low pressure operations
• poor ability to handle start up air loads
• poor operation against back pressure
• good resistance to damage from freezing
• excellent ability to purge system
• poor performance on very light loads
• delayed responsiveness to slugs of condensate
• poor ability to handle dirt
• small comparative physical size
• poor ability to handle flash steam
• open at mechanical failure

Industrial Zone classification

Happy New Year!!!

Know about the Industrial safety Zone Classification.

This will be the first class , if you get into any chemical industry.

Find the Protected Document file in below link and have a look on that.

With Best wishes

Karthik

http://www.esnips.com/doc/57ec9ecd-aa4f-4f15-a430-714795995b29/safety

Pressure Drop Calculation - Karman method

Pressure drop calculation based on Karman method enclosed here....

Karman worksheet attached in Public folder.

http://www.esnips.com/doc/736b0da8-db5c-4581-9cab-48b4a8e6cd74/karman_dp

Experienced - Based Rules of Chemical Engineering

Experienced based rules of chemical Engineering enclosed in a public folder.

Find the link below and make use of it.

http://www.esnips.com/doc/bae3e55b-e6eb-4cc4-8970-f5f3587ce45a/exprules

Father of Chemical Engineering

From the 1700s, sodium and potassium carbonate were in great demand in the manufacture of a wide range of products including glass, soap and textiles. A frenchman, Nicholas Le Blanc, invented a method for converting sea salt into sodium carbonate which was in widespread use by 1810. However, the process produced hazardous by-products including hydrochloric acid, nitrogen oxides, sulphur and chlorine gas, which often escaped or were released to the atmosphere where they damaged public health and the environment.

Widnes in Cheshire in the early 1800s, under the cloud of the Leblanc process the IChemE

A. J. Fresnel developed new, clean chemistry in 1811, but attempts to build large scale factories using it failed until, over 50 years later in 1863, a Belgian, Ernest Solvay applied it in what became known as the Solvay process.
The Solvay process featured an 80 foot tall high-efficiency carbonating tower, in which ammoniated brine was poured down from the top while carbon dioxide bubbled up from the bottom, producing the desired sodium carbonate. The new process operated continuously, free of hazardous by-products and with an easily purified final product. Solvay's process relied on intimate contact between the gas and liquid. Although it was not established as a profession at the time, Solvay's work is thought of as one of the first triumphs of Chemical Engineering.

The Father of Chemical Engineering

George Davis (1850-1907). Founder of the profession the IChemE

In the 1800s, the chemical industry was compartmentalised; plants were designed and run by specialists. George E Davis, adopted as the father of Chemical Engineering, identified broad features in common to all chemical factories. He was author of A Handbook of Chemical Engineering, published a famous lecture series defining Chemical Engineering in 1888 and was founder of the concept of unit operations.
Whilst Chemical Engineering took off as a distinct profession in America, in the U.K. it is only since the second world war that the value of chemical engineers has become truly appreciated. This change has been driven to a large extent by the expansion of the oil industry; the first oil refinery in the U.K., and still the largest, was built by Esso at Fawley after the war. Chemical engineers have subsequently played a key role in the growth of the petrochemical and plastics industries.