E dady Informaction

Our Story.........

The world is changing. Yes, we all know that but there are a few things in life that haven’t changed much. Take shopping for example. You find something appealing; spend money on it and its yours….until it lasts. Internet may have changed the shopping game a little but the dynamics still remain the same. Spend money, get your money’s worth and spend some more. What’s the point of spending if the benefits of your purchase last till its expiry date? Why spend money on something that will break or decay over a period of time?

Sure, this may be the fate of every product; but not at eDady. eDady has taken the shopping game a step further by filling your shopping cart with benefits that may last longer than your purchase. Sounds dubious? It sure does. Because eDady is all set to revolutionize the shopping experience.

Bringing together a roster of alluring and mind blowing products, eDady doesn’t just make you shop till you drop, but also gives you a chance to get something twice as amazing as the product itself. Combining some of the finest elements from network marketing, MLM and direct selling; eDady has laid the foundation of a unique system where shoppers get more than just the product, but an amazing compensation plan that is not just fabulously lucrative, but so flexible that it feels like its custom tailored for the consumer.

Simple, risk free, extremely rewarding and flexible is what the amazing system of eDady is all about. With a wide selection of products to choose from and a compensation plan as an added bonus with every product, eDady assures that shoppers get more than just their products; but an opportunity to unfold a bright and prosperous future . At eDady, we don’t just sell an item; but we sell the ticket to a glorious tomorrow almost for no price. So what are you waiting for? Buy something, become an ambassador and climb aboard the ship that always sails in one direction………success.

Our Mission

eDady is not your average, run of the mill shopping portal where purpose is just to purchase a few goods and be on your way. eDady takes the notion of shopping one step further by creating a long lasting bond between the buyer and the seller where the collective benefits are mutual. In a world where opportunity to provide a steady source of income is as precious as gold, eDady strives to generate a lucrative stream of benefits to its ambassadors whenever they make a purchase from its online store.

eDady wishes to transcend the consumer and seller relation to an entirely new level where a shopper ends up earning a handsome amount while spending less. With such high moral and financial standards, we consider our customers the ambassador of the eDady philosophy thus elevating their status from a mere consumer to an honorable ambassador.

Based upon some of the best feature of MLM and network marketing, eDady’s pride is its insanely flexible compensation plan that distinguishes it from regular multi level marketing or network marketing companies who smother their customers with unrealistic and painfully tight compensation plans with nothing but dimes and peanuts for reward.

This is the ultimate goal of eDady; to be pioneer of a system where every ambassador is given a chance to get more out of his purchase. With our amazing selection of products and extremely attractive compensation plans, eDady is a name that we wish to associate with prosperity and trust.

Amazing Income

eDady is all about taking the shopping experience to the next level. How often does a customer get more, maybe twice or thrice more of the value of his or her purchase? The honest answer is either never or rarely. With eDady, every customer is an honorable ambassador and gets a ticket towards fortune and glory beside the purchased merchandise. And the greatest thing about this awesome system is that you don’t need to have a PhD to understand it unlike the other MLM and Network Marketing based schemes that are so complex and riddled with glitches that most of their customers end up paying more rather than what they bargained for. Not with eDady. It adapts to your needs and your spending power this granting you to become a part of an amazing income plan despite of the volume of your purchase.

For starters, eDady doesn’t have a traditionally laid out compensation plan which must be selected at the time of purchase. Your purchase IS your compensation plan. That’s right; no more going through catalogues or going through the dubious choices relating to picking up a reward plan which may suit you. eDady’s Smart Purchasing System automatically develops a compensation plan for you the moment checkout your shopping cart giving you an instant opportunity to multiply the worth of your spending manifolds.

Here is the simple breakdown:

Let’s say you make a purchase of 10 eDB from eDadys store. The purchase despite it’s worth automatically generates a compensation plan for you. Most compensation or reward plans in other MLM or network marketing based reward plans are tied to specific number of referrals on both sides of the virtual tree of their customers where a customer has to toil hard to recruit more customers in a certain pair pairing order to be able to earn rewards and commissions. eDady doesn’t bound its valuable ambassadors with constrictions like these. Commission in eDady is dependent on the sales volume corresponding to the ambassador’s compensation plan. The moment both sides of the ambassador’s referral tree hit that volume, the ambassador gets entitled for the commission. And the great part is, commission is given to the ambassador every time both of his referral side touches the required sales volume. In comparison to other network marketing based fiascos, its double the commission without the bondage of herding sets of individuals under both wings of your virtual tree.

Top Earning Sites...

E dady

For More Info...     Click here

Boiler Water Test

Corrosion and tube failure caused by water chemistry

Recommended ranges( Co-ordinated phosphate treatment for w/t boiler )

pH	- 9.6 to 10.3
PO4	- 4 to 20 ppm
N2H4	- 0.01 to 0.03 ppm
TDS	- < 150 ppm
Cond pH	- 8.6 to 9.0
Cl	- 20 ppm
O2	- 10 ppb
Si	- 10 ppb

 Chlorides

1. • Measure 100ml of sample water into a casserole
   • Add 10 drops phenol pthalein (RE 106)
   • Neutralize with sulphuric acid
   • Add 10 drops of Potassium Chromate
   • Titrate Silver Nitrate untill sample just turns brick red
   • ppm as CaCO₃= (ml x 10) ppm

TDS

1.  
   • Measure 100ml of sample water into a casserole
   • Add 10 drops of phenolpthalein
   • Neutralise with TDS reagent (acetic acid)
   • Temperature compensate then read off scale in ppm.

Phosphates

1.  
   • Fill one 10 ml tube with distilled water
   • Fill one 10 ml tube with boiler water tests.
   • Add 0.5 ml sulphuric acid (RE 131) to each
     Add 0.5 ml Ammonium Molybdnate (RE130) to each
     Add 0.5 ml Aminonapthol Sulfonic acid (RE 132) to each
     Stir well between each addition
   • Wait 3 minutes for calorimetric compaisonAlternately Vanado-molybdnate test
     
   • Place 5 ml boiler water in 10 ml tube
   • Place 5 ml distilled water in other 10 ml tube
   • Top both to 10 ml with Vanado-molybdnate reagent
   • Place in colour comparator and compare after 5 mins

Hydrazine

1.  
   • Add 9ml distilled water to one tube
   • Add 9 ml boiler test water to anouther
   • Add 1 ml hydrazine reagent to each
   • Use colour comparator

Alkalinity Phenolpthalein

1.  
   • 100 ml filtered water
   • Add 1 ml phenolpthalein
   • If pH >8.4 Solution turns pink
   • Add H₂SO₄ untill pink disapears
   • Ml 0.02N H₂SO₄ x 10 = ALk in CaCO₃ ppm
   • Measures hydroxides and carbonates in sample, bi-carbonates do not show up so sample should not be allowed to be exposed to the air for too long

Alkalinity Methyl orange

1.  
   Bi carbonates do not show up in the phenolpthalein sample as they have a pH < 8.4. Bi carbonates can not occur in boiler but if suspected in raw feed then the following test.
   • Take phenolpthalein sample, add 1 ml methyl orange
   • If yellow, bi carbonates are present
   • Add H2SO4 untill red
   • Total 0.02N H₂SO₄ x 10 = Total Alk in CaCO₃

pH

1.  
   • 100 ml unfiltered sealed water poured into two 50 ml glass stoppered test tubes
   • Add 0.2 ml pH indicator to one ( pH indicator vary's according to required measuring range)
   • Use colour comparator
   • Due to difficulty of excluding air, electronic pH meter preferred  

Sulphite reserve

1.  
   • Exclude air at all stages
   • 100 ml unfiltered water
   • Add 4 ml H₂SO₄ + 1 ml starch
   • Add potassium iodate-iodide untill blue colour
   • ml Iodate-Iodide sol x 806 / ml of sample = SO₃ reserve in ppm

Ammonia in feed

1.  
   • Only necessary where N₂H₄ used in blr
   • Pour condensate sample into two 50 ml colour comparator tubes
   • Add 2 ml Nessler reagent to one
   • Wait 10 mins
   • Use colour comparator   
   
   

   Boiler water treatment

   Alkalinity

   
   

   Treatment

   For pressures below 20 bar dissolved O₂ in the feed does not cause any serious problems so long as the water is kept alkaline
   However cold feed should be avoided as this introduces large amounts of dissolved O₂ are present, for pressures greater than 18.5 bar a dearator is recommended

   Feed Treatment Chemicals

   Sodium	Hydroxide
   Calcium	Bicarbonate (CaCO3 + Na2CO3)
   Magnesium	Bicarbonate
   Magnesium	Chloride.
   .	.
   Sodium	Phosphate
   Calcium	Carbonate
   Calcium	Sulphate
   Magnesium	Sulphate
   All in this column precipitated as hydroxide or phosphate based sludges	All in this column form sodium salts which remain in solution

2. Sodium Hydroxide
   • Reacts with highly corrosive MgCl₂
   • Does not readily react with CaSO₄
   • Strongly alkaline
   • Produces heat when mixed with water
   • Absorbs CO₂ changing to Sodium Carbonate
   • Unsuitable for standard mixes

• Sodium Carbonate Na₂CO₃ ( soda ash )
  • Alkaline
  • At pressures above 14 bar some of the Sodium Carbonate decomposes to form NaOH and CO₂ . Increasing on pressure increase
  • Changes to Sodium Bi-Carbonate when exposed to air
  • Still usable but larger amounts make control difficult
  • Standard mix ingredient

• Sodium Hexa Meta Phosphate NaPO₃ (calgon)
  • Safe,soluble in water, slightly acidic
  • May be injected any where as will only react in the boiler
  • Suitable for LP blrs which require lower alkalinity

• DiSodium Phosphate Na₂HPO₄ (Cophos II)
  • Neutral used with alkaline additive
  • Combines with NaOH to give trisodium phosphate
  • Basic constituent

• TriSodium Phosphate Na₃ PO₄ (Cophos III)
  • Alkaline
  • When added to water decomposes to NaOH and Na₂ HPO₄
  • As water evaporated density increases and NaOH and Na₂ HPO₄ recombine
  • Phosphates can form Phosphides which can coat metal to form a protective barrier, with excessive phosphate levels, this coating can be excessive on highly rated boilers operating at higher steaming rates

Chemicals are normally added as a dilute solution fed by a proportioning pump or by injection from pressure pot.
Use of chemicals should be kept to a minimum.

Injection over a long period is preferable as this prevents foaming.

Excessive use of phosphates without blowdown can produce deposits of phosphides on a par with scale formations.

Therefore it is necessary to add sludge conditioners particularly in the forms of polyelectrolytes, particularly in LP blrs

Oxygen Scavengers

• Hydrazine N ₂ H ₄
  • Oxygen scavenger, continously injected to maintain a reserve within the boiler of 0.02 to 0.1 ppm and a feed water O₂ content of less than 10 ppb
  • At temperatures greater than 350^oC , will decompose to ammonia and nitrogen and will aid in maintaining balanced alkalinity in steam piping.Steam volatile, neutralises CO₂
  • Inherent alkalinity helps maintain feed water alkalinity within parameters of 8.6 to 9.0.
  • Used in boiler operating above 32 bar, will not readily react with O₂ below 50^oC hence risk of copper corrosion occurs with the ammonia stripping off the continuously reforming copper oxides.
  • Supplied as a 35% solution

• Carbohydrazide (N ₂ H₃)₂CO
  • Is a combined form of Hydrazine
  • It is superior to hydrazine in performace and is designed to minimise the vapours during handling
  • Carbohydrazide and its reaction products create no dissolved solids
  • Is an oxygen scavenger and metal passivator at both high (230'C) and low (65'C) temperatures
  • Can be used with boilers up to 170 bar

• Diethylhydroxylamine DEHA
  • Like hydrazine, provides a passive oxide film ( magnetite) on metal surfaces to minimise corrosion
  • Contributes to pH netralisation to an extent that seperate condensate control may not be necessary
  • Protects entire system-feedwater, boiler and condensate

• Sodium sulphite Na₂SO₃
  • Takes the form of a soft white powder
  • Slightly alkaline
  • Will react with oxygen to form Sodium Sulphate at about 8ppm Sodium Sulphite to 1ppm Oxygen
  • Use limited to low pressure boilers due to increasing TDS and reducing alkalinity by its action

• Tannins
  • Certain alkaline tannin solutions have a good oxygen absorbing ability with about 6ppm tannin able to remove 1ppm oxygen.
  • The reaction with oxygen is complex and unreliable, no official reserve levels exist for the maintenance of a system using tannin

• Erythorbic Acid (Sur-gard) R₁-C(OH)
  • An effective oxygen scavenger and metal passivator
  • It is the only non-volatile scavenger which can be used with spray attemperation
  • does not add measureable solids to the boiler water
  • May be used in boilers up to 122 bar
  • Officially recognised as a Safe Substance
  • As with hydrazine a small amount of ammonia is created in the boiler, it is not recommended for layup.

Polymer Treatment

Polymer is a giant molecular built up by stringing together simple molecules

E.G.
Polyelectrolytes-Formed from natural or synthetic ionic monomers
Polyacrylates - Polymers of acrylic acid
Polyamides - Polymers of amides

Polymer treatment prevents scale formation and minimises sludge formation. It can also loosen scale so established blrs introduced to this form of treatment may develop leaks where previously plugged with scale. Especially in way of expanded joints. Also can absorb trace oil

Use limited to LP blrs as no PO₄ present to prevent caustic alkalinity

For auxiliary blrs this is a superior form of treatment to the old alkaline and phosphate treatment. The correct level of alkalinity must be maintained as too low a level neutralises the electric charge of the polyelectrolyte. Too high causes caustic alkalinity.

Amine treatment

Compounds containing nitrogen and hydrogen.

Neutralising amines

Hydrazine N₂H₄

see above

Bramine ( cyclohexalamine )

(Bull & Roberts amine treatment)

Neutralising amine as with hydrazine. Used with hydrazine to maintain feed water alkalinity within parameters. As a knock on effect will slightly increase boiler water alkalinity.

Stable at high temperatures so is used more than hydrazine to control the steam line alkalinity as there is less chance of copper corrosion which occurs with the prescience of ammonia

Proper boiler water treatment eliminates sludge and scale deposits within the boiler. However, over along period of time a film of copper and iron oxides build up on the tube surface. Most of these oxides are transported from oxides of corrosion within the feed system to the boiler with the condensate.

Bramine reduces this corrosion and eliminates the build up of these oxide deposits.

Mechanism of function
Condensate from the condenser is very pure and slightly acidic, often referred to as 'hungry water'. It can dissolve metals in trace amounts to satisfy this hunger.
Distilled make up water aggravates this situation containing much dissolved CO2 and hence being acidic carries its own corrosion products.
Trace amounts of bramine are introduced into the system to establish an alkalinity level greatly reducing the effects of the hungry water.

Some of the bramine is used almost immediately, most however, passes on to the boiler where it is then transported through boiler water, boiler stm drum, stm lines back to the condenser. It has no effect anywhere except the condensate system.

Bramine also has a cleaning effect and may assist in the cleaning the film off the tube over a period of time.
Bramine is safer to handle than Bramine and will protect all metals.

Hydrazine however readily breaks down to form ammonia which whilst protecting ferrous metals will attack those containing copper

Filming amines

Shows neutralising tendencies, main function however is to coat piping with a molecular water repellent protective film

Injection of amines
May be injected between HP and LP turbines in the X-over pipe or after the dearator.
Adding in X-over pipe-reduces corrosion of copper alloys
Dearator only effective as a feed heater

Adding after dearator -Dearator correctly performing as a dearator and feed heater. If possible the best system is to have a changeover to allow norm inj into the X-over at sea and injection after the dearator when the turbine shut down

Limits of density/pressure

Sludge conditioning agents

• Coagulants-
  • Mainly polyelectrolytes
  • Prevents the precipitated sodium based particles forming soft scales
  • Will keep oil in an emulsion
  • the water must be kept alkaline

• Antifoams
  • reduce the stability of water film around steam bubble and cause it to collapse.
  • Common type polyamide is an organic compound of high molecular weight.
  • In the event of severe contamination separate injection of an antifoam is recommended

• Dispersing agents
  • Sludge conditioners such as starch or tannin.
  • Prevent solid precipitates uniting to form sizeable crystals e.g. MgSO4

Treatment in boilers (non congruent)

LP tank blrs (<14 bar)

Na₂CO₃- precipitates salts, provides alkalinity
MgSO₄- Sludge conditioners

Na₂CO₃ can break down to form NaOH in higher rated boilers hence initial dose with Na₂SO₄

Medium pressure tank blrs (<17.5 bar)

Na₂CO₃(3) + sodium phosphate(4) + sludge conditioners(1)

Medium to High pressure water tube <60 bar

Na₂CO₃ + Na₂HPO4 +sludge conditioners

Oxygen scavengers also used to allow magnetite (Fe₃O₄) layer to form in the boiler

Boiler operating above 42 bar require a dearator.

HP to UHP blrs (42 to 80 bar)

Due to level of decomposition of Na₂CO₃ . NaOH preferred for better controllability Na₂HPO₄

NaOH attacks the magnetite layer. Congruent treatment used.

Permissible limits

		Shell	WT	WT	WT	WT	WT
TEST>	PPM	<17.5b	<17,5b	<32b	<42b	<60b	<85b
Hardness	CaCO3	<=5	<=5	<=5	<=1	<=1	<=1
P.alk	CaCO3	150-300	150-300	150-300	100-150	50-100	50-80
T.D.S.	CaCO3	<=7000	<=1000	<=1000	<=500	<=500	<=300
Cl	CaCO3	<=1000	<=300	<=150	<=100	<=50	<=30
PO4	PO4	30-70	30-70	30-70	30-50	30-50	20-30
N2H4	N2H4	--	--	--	0.1 -1.0	0.1 - 1.0	0.1 - 1.0
SO3	SO3	50-100	50-100	50-100	20-50	--	--
SiO2	SiO2	--	--	--	--	--	<=6.0
Fe	Fe	--	--	--	--	--	<=0.05
Cu	Cu	--	--	--	--	--	<=0.02
pH	pH	10.5-11	10.5-11	10.5-11	10.5-11	10.5-11	10.3-11
Limits for feed water
Cl	CL	<=10	<=5	<=1.0	<=1.0	<=1.0	<=1.0
O2	O2	----	----	<=0.006	<=0.003	<=0.015	<=0.01
NH3	NH3	----	----	----	-----	-----	<=0.5
Fe	Fe	----	----	----	-----	<=0.01	<=0.01
Cu	Cu	----	----	----	-----	<=0.01	<=0.01
pH	pH	----	----	----	8.5-9.2	8.5-9.2	8.5-9.2

Boiler Mounting

Definition - various valves and fittings are required for the safe and proper working of a boiler . Those attached directly to the pressure parts of the boiler are referred to as the boiler mountings.

Minimum requirements for boiler mountings

•  
  • two safety v/v's
  • one stm stop
  • two independent feed check
  • two water gauge or equivalent
  • one pressure gauge
  • one salinometer v/v or cock
  • one blowdown/scum v/v
  • one low level fuel shut off device and alarm

Functions

SAFETY V/V-protect the boiler from over pressurisation. DTI require at least two safety v/v's but normally three are fitted ,two to the drum and one to the superheater. The superheater must be set to lift first to ensure a flow of steam through the superheater.
These must be set to a maximum of 3% above approved boiler working pressure.MAIN STM STOP-mounted on supherheater outlet header to enable boiler to be isolated from the steam line if more than one boiler is connected. V/v must be screw down non return type to prevent back flow of steam from other boiler into one of the boilers which has sustained damage (burst tube etc) v/v may be fitted with an emergency closing device.
AUXILLIARY STOP V/V- similar to main stops but connected to the auxiliary steam line
FEED CHECK V/V'S- a SDNR v/v so that if feed p/p stops the boiler water will be prevented from blowing out the boiler. The main check is often fitted to the inlet flange of the economiser if no economiser fitted then directly connected to the boiler. The Auxiliary feed check is generally fitted directly to an inlet flange to the drum with crossovers to the main feed line. Usually fitted with extended spindles to allow remote operation which must have an indicator fitted. 

WATER GUAGES- usual practice is to fit two direct reading and at least one remote for convenient reading.
PRESSURE GUAGES-fitted as required to steam drum and superheater header
SALINOMETER COCKS OR V/V'S-fitted to the water drum to allow samples to be taken.Cooling coil fitted for high pressure boilers.
BLOWDOWN COCK- used to purge the boiler of contaminants.Usually two v/v's fitted to ensure tightness . These v/v's lead to an overboard v/v.
SCUM V/V-These are fitted where possibility of oil contamination exists. They are designed to remove water and/or contaminants at or close to normal working level.

SAFETY VALVES

At least two safety valves have to be fitted to the boiler. They may be both mounted on a common manifold with a single connection to the boiler. The safety valve size must not be less than 38mm in diameter and the area of the valve can be calculated from the following formulaC x A x P = 9.81 x H x E
where
H= Total heating surface in m³
E = Evaporative rate in Kg steam per m² of heating surface per hour
P = Working pressure of safety valves in MN/m² absolute
A = Aggregate area through the seating of the valves in mm²
C = the discharge coefficient whose value depends upon the type of valve.
C=4.8 for ordinary spring loaded valves
C=7.2 for high lift spring loaded valves
C= 9.6 for improved high lift spring loaded valves
C= 19.2 for full lift safety valves
C= 30 for full bore relay operated safety valves

LIFT PRESSURE

The safety v/v must be set at a pressure not exceeding 3% of the approved boiler working pressure. It is normal to set the suphtr safety below that of the drum to ensure an adequate flow of stm for cooling purposes under fault conditions. Similarly the superheater should be set to close last.

10% ACCUMULATION OF PRESSURE RULE.

With all the flames in full firing the stm stop is closed, the boiler pressure must not increase by more than 10% in 7 minutes for water tube of 15 mins for tank boilers with the safety lifted. this is normally waivered for superheater boilers. Instead calculations and previous experience used.

BLOWDOWN

The pressure drop below the lifting pressure for a safety v/v is set at 5% by regulation although it is more normal to set v/v's at 3% to prevent excessive loss of stm. For boilers with a superheater it is important that the superheater v/v not only lifts first but closes last.Adjustement of the blowdown may be necessary following adjustment of the popping setpoint (Increaseing set point lengthens blowdown). Adjustment is achieved by altering the height of the 'adjusting guide ring' on the full lift safety valve design shown below. Over raise adjustment of this ring can lead to mal-operation with the valve not fully opening

SETTING

Must be set with the surveyor present except when on the waste heat unit. A chief engineer with three years experience may then set the safety valve but must submit information to surveyor for issue of certificate.
Superheated steam safety valves should be set as close to operating temperature as possible as expansion can alter the relationships between valve trim and guide/nozzle rings which can effect the correct operation of the valve.

1.  
   1. Two safety valves- each set independently
   2. Each safety valve must release entire steam flow in pressure accumulation test
   3. Surveyor uses specially checked gauge
   4. One valve gagged
   5. valve initially set to approximately the correct position then steam pressure increased to set pressure
   6. adjust valve to lift
   7. raise and lower pressure to check
   8. fit locks to both valves on completion

Easing gear to be checked free before setting valves. Steam should not be released as this can damage seat.

Improved high lift safety valve

Differences in the ordinary and high lift designs

Ordinary	High Lift	Improved high lift
Winged valve	Winged valve	Wingless valve
No waste piston	Waste piston	Waste piston
	No floating ring	Floating ring

For superheated steam the aggregate area through the seating of the valves is increased, the formula is
As = A(1 + Ts/555)
where
As = Aggregate area through the seating of the valves in mm² for superheated steam
A = Aggregate area through the seating of the valves in mm² for sat steam
Ts = degrees of superheat in ^oC
As is greater than A due to the higher specific volume of superheated steam requiring more escape area.
The manifold pipe must have an area equal to at least Н of A, the exhaust must have a diameter dependent on the type of valve but up to 3 x A for a full bore relay operated valve.
A drain pipe must be fitted to the lowest part of the valve, it should have no valve or cock and should be checked clear on regular occasions.

Materials

Materials for all parts must be non corrodible. Common materials are Bronze, Stainless steel or Monel metal, depending on the conditions of service. The valve chest is normally made of cast steel.

Full lift safety valve

This is a modern version of the high lift safety valve incorporating the piston and reaction force effects to improve valve lift. In addition the inlet pipe is tapered to give a nozzle effect increasing the reaction on the lid.
The initial lift is produced when the steam pressure under the disc exceeds the spring pressure. As the valve begins to open a thin jet of steam escapes and is deflected by a small angle on the nozzle ring. As the lift increase the steam begins to react against upper guide ring increasing to 'full bore'lift. Full Borelift is defined as that point where the area of the nozzle, rather than the lift, limits the discharge capacity of the valve. The form of the valve offers an increased area to the steam jet stream and the design allows for a piston effect of the valve trim assembly as it enters in the guide ring cylinder, both these effects increase lift and improve action of the valve
The guide sleeve is adjustable allowing alteration of the blowdown.
With boiler pressure dropping the valve begins to close. When the lid just exits the guide sleeve there is a loss of the reaction and piston effect and the valve tends to snap shut cleanly.
Blowdown adjustment is achieved by altering the height of the adjusting Guide Ring. On some designs a second adjustable ring is mounted on the nozzle, this allows adjustment of the 'warn' or 'simmering'period and increases the popping power. Adjustment of this ring is critical to operation, after factory setting it is generally unnecessary and no attempt should be made to remove slight 'warn'

Full lift safety valve

Seen fitted to large high pressure boilers.

•  
  • Complicated design to achieve high lift is obviated
  • Pilot valve may be mounted on the drum and the main valve maounted on the superheater thus making the system more sensitive to load changes (over pressurisation will first be seen in the steam drum before the superheater. In addition the pilot valve and main valve piston arrangements are subject to lower steam temperatures
  • Boiler pressure will assist to close the main valve rapidly leading to very small blowdown
This design offers sveral advantages over simple high lift valves

Easing gear

This is fitted to safety valves to allow manual operation of the valve in an emergency.

Gauge glasses

General

The requirements are that there must be two independent means of reading the boiler water level. Normal practice for propulsion plant boilers are the fitting of two direct reading level gauges and a remote display readout.

Low pressure boilers( up to 17.5 bar)

Small vertical boilers may be fitted wit a series of test cocks to ascertain the level, this is deemed unsuitable for boilers above 8.2 bar and/or 1.8m in diameter.

Tubular gauge glass

Medium pressure boilers

Reflex glass is used due to the fact that light falling on the glass is reflected by the steam but not by water, and so the glass appears bright where there is steam and dark where there is water.

High pressure boilers

A ball is located in the water side to prevent large quantities of water entering the engineroom in the event of the glass failing and the subsequent large expansion of the water as it flashes off to steam. An orifice restrictor is fitted to the steam valve.
Mica is placed on the water side of the glass to protect against erosion and chemical attack of the high temperature water.

General gauge glass faults

Due to the evaporation of water leaking through the cock joints a build up of deposits can occur. This leads to restriction and eventual blockage of the passage. If this occurs on the steam side then the level tends to read high as the steam condenses.
Another reason for blockage is the cock twisting, hence the cocks are all arranged so that in their normal working positions, i.e. steam/water open , drain shut, the handles are all pointing downwards. Possibility of the sleeving rotating on the cock has led to the use of ribbed asbestos sleeves which must be carefully aligned when fitting.
For tubular gauge glasses the length of the tube is critical and should be checked before fitting

Bi-color gauges

Igema remote reading indicator

Fitted in addition to gauges required by statute and not in place of them. The red indicator fluid does not mix with the water
Equilibrium condition is when H= h + rx where r is the specific density of the indicator fluid.
If the water level rises h increases and x reduces. Therefore H will be reduced and water will flow over the weir of the condenser to maintain the level constant. If the water level were to fall h would be reduced, x increase and H would be increased. Water therefore must be made from condensing steam in order to keep the condenser level constant.