Part 15 (2/2)
047(T - t_{2}) = --------------- (6) L
As T and t_{2} are taken with the same thermometer under the sa of the thermometers will be approximately the same for the temperatures T and t_{2} and the above method therefore corrects for both the radiation and thers for dry steam, where there are no losses due to radiation, are obtainable fro for t_{2} The difference between the theoretical reading and the nor for no moisture will be the thermometer and radiation correction to be applied in order that the correct reading of t_{2} e of its ordinary use, such a ther is approximately correct for any conditions with the sae of moisture in the steam, corrected for thermometer error and radiation and the correction to be applied to the particular calorie pressure in the trial to be 180 pounds and the ther, taken in the rees; then, the percentage of moisture corrected for thermometer error and radiation is,
047(303 - 295) x = ---------------- 8450
= 045 per cent
The theoretical reading for dry steam will be,
11977 - 11504 - 047(t_{2} - 212) 0 = ------------------------------------ 8450
t_{2} = 313 degrees
The thermometer and radiation correction to be applied to the instrue of pressure is
Correction = 313 - 303 = 10 degrees
The chartof e and the permanent radiation correction for the instrument used without computation as follows: assume the sa as above If the norrees, the correction for ther for dry stearees correction The correct terees The e pressure will be found fro 16 Co Calori calorimeter, all of which work upon the sa 14
An extre 16 This calorimeter consists of two concentrica there placed in the supply pipe or other convenient location Steah the orifice A and expands to at measured by a thermometer placed in the cup C To prevent as far as possible radiation losses, the annular space between the two cylinders is used as a jacket, steah the hole B
The li calorimeter ork are, at sea level, froe pressure and 717 per centCalori calorimeter mechanically separates the entrained water from the steam and collects it in a reservoir, where its alass or is drained off and weighed Fig 17 shows a calorimeter of this type The steah an orifice of known size so that its total ae is ordinarily provided with this type of calorimeter, which shows the pressure in its inner chaiven period, this latter scale being graduated by trial
The instru calorimeter, should be well insulated to prevent losses fro calorimeter is not lie of h, to attach a throttling calori of the separating calori nozzle and the throttling instrument, and is necessary to insure the detere of es shown by the two instruments is thethrough a separating calorimeter may be calculated by Napier's for known There are objections to such a calculation, however, in that it is difficult to accurately determine the areas of such small orifices Further, small orifices have a tendency to become partly closed by sediment that may be carried by the stea the ah the instru 17 Separating Calorimeter]
A hose should be attached to the separator outlet leading to a vessel of water on a platforraduated to 1/100 of a pound The steam outlet should be connected to another vessel of water resting on a second scale In each case, the weight of each vessel and its contents should be noted When ready for an observation, the instruhly so that there will be no water within the separator The separator drip should then be closed and the steam hose inserted into the vessel of water at the same instant When the separator has accumulated a sufficient quantity of water, the valve of the instrument should be closed and the hose removed from the vessel of water The separator should be eht of each vessel and its contents are to be noted and the differences between the final and original weights will represent the weight of ht of steam from which the moisture has been taken The proportion offormula:
100 w x = ----- (7) W - w
Where x = per cent ht ofcalori Nipple--The principle source of error in steam calorie sample of the steam delivered by the boiler and it is extremely doubtful whether such a sa features in the obtaining of such a sa nozzle used and its location
The A nozzle made of one-half inch iron pipe closed at the inner end and the interior portion perforated with not less than twenty one-eighth inch holes equally distributed froular or spiral roith the first hole not less than one-half inch froineers object to the use of a perforated saher percentage of moisture than is actually present in the steam This is due to the fact that if the perforations come close to the inner surface of the pipe, the s to this surface, will flow into the calorie error Where a perforated nipple is used, in general it may be said that the perforations should be at least one inch fro nipple, open at the inner end and unperforated, undoubtedly gives as accurate a measure as can be obtained of thethat end It would appear that a satisfactory e sample of the steam would result froh a stuffing box which would allow the end to be placed at any point across the diameter of the steaine turbine unit, Mr
H G Stott and Mr R G S Pigott, finding no experi on the subject of low pressure steaation of the subject and the sa 18 was developed In speaking of sa nozzles in the determination of the ott says, ”the ordinary standard perforated pipe sa a true sample and it is vital that the sa its direction or velocity until it is safely within the sample pipe and entirely isolated fro 18 Stott and Pigott Sa Nozzle]