US3294069A

US3294069A - Steam boiler system

Info

Publication number: US3294069A
Application number: US496262A
Authority: US
Inventors: Frank J Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-10-15
Filing date: 1965-10-15
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27

Description

F. J. SMITH STEAM BOILER SYSTEM Filed 0G12. l5, 1965 Dec. 27, 1966' United States Patent O 3,294,069 STEAM BOILER SYSTEM Frank J. Smith, 7351 Limeklin Pike, Philadelphia, Pa. 19138 Filed Oct. 15, 1965, Ser. No. 496,262 4 Claims. (Cl. 1221) This invention relates to a steam boiler system, particularly to an improved sys-tem of high pressure and low pressure steam boilers and related equipment, of the type having substantial make-up water demands, arranged in a unique operational combination, and has for an object the provision of improvements in this art.

With the exception of low pressure steam heating systems in which the condensate is returned to the boilers with little or no loss and therefore little or no makeup, the problem of scale deposits and corrosion of the internal surfaces of the metal comprising the shell plates, heads, drums, and tubes of the boilers is of universal concern.

The problem becomes more acute as steam pressures and related temperatures are increased. Since scale is an insulation that retards transfer of heat from the hot metal of the boiler surfaces to the water, increasing thicknesses of scale result in increased metal temperatures and ultimate failure of the metal.

All makeup boiler feedwaters, whether from municipal systems or from wells, lakes or streams, contain in varying amounts corrosive gases and harmful dissolved salts. Treating systems range from simple methods of introducing chemicals directly into the boiler itself to elaborate and expensive external systems incorporating the use of deaerating equipment to remove as much of the corrosive gases as possible, the use of ion exchange systems of either, or a combination of, sodium and acid cycles that are capable of producing water of almost any degree of chemical purity.

Boiler feedwater purification by means of distillation is practiced only in systems involving extremely large high pressure and high temperature boilers such as in public utility plants, where pure water is vitally needed to avoid burned out tubes and turbine blade deposits caused when small amounts of impurities are carried into the boilers with the feedwater.

There are many installations, as in laundries, dairies, dye houses, food processing plants, and the like, where the sys-tem disclosed herein can be advantageously used to provide distilled and deaerated feedwater to the high pressure boiler or boilers and furnish an excess amount of this relatively pure water for special processes and for sale on the market.

Accordingly, it is a particular object of the present invention to provide a system in which a high pressure boiler system is supplied with deaerated condensate from its own system plus needed makeup deaerated condensate supplied from a low pressure boiler system, which system, in turn, has been supplied with deaerated water from a softening system.

Another object of the invention is to permit the use of steam generating equipment for operation at substantially increased pressures and temperatures than is now cornmonly used, thereby increasing the economic efficiencies of the plants by permitting the use of more etlicienft pumps, fans, blowers, and turbo electric generators not possible when operating at lower pressures and temperatures.

Another object is to provide a system which supplies highly purified deaerated distilled water as an economical by-product for use wherever needed.

The above and other objects of the invention, as well as various novel features and advantages, will be apparent from the following description of an exemplary embodi- "ice ment, reference being made to the accompanying drawings thereof, wherein:

The single figure is an elevational diagram of an installation or sys-tem embodying the invention.

In the drawings there is shown a low pressure steam boiler 10, a high pressure steam boiler 11, a water softener unit 12, a heat exchange water heater 13, a steam load demand 14 of the high pressure boiler, a feed water deaerating heater unit 15 for the low pressure boiler, a condensate deaerating heater unit 16 for the high pressure boiler, a storage tank 17 for the deaerating heater unit 16, and a reservoir 18 for highly purified water.

A pipe line 20 supplies raw water to the sof-tener 12; a pipe line 21 supplies soft water from the softener to the exchange water heater 13; a pipe line 22 carries hot offtake water from the heater 13; a first branch pipe line 23 carries water from the pipe 22 and heater 13 to the process demand means 24; and a second branch pipe line 25 carries water from the pipe line 22 and heater 13 to supply the low pressure boiler 10.

Water from the pipe line 25 is not fed directly into the low pressure boiler 10 but is first passed by a pipe line 26 into the top of the feed water deaerating heater 15 where steam from a branch line 27 of the low pressure boiler 10 is supplied for the de-aerating action of the condensate deaerating heater 15. Steam to deaerating heater 16 is supplied by a branch pipe line 59 from the low pressure boiler 10. A pipe line 28 takes deaerated water from the unit 15 to the header drum 29 of the boiler 10. A valve 30, responsive to the level of water in the header 29, controls the iiow of water to the pipe line 26 and lthe deaerating heater 15.

Steam from the header drum 29 Iof the low pressure boiler 10 flows by way of a pipe line 33 to a heating coil 34 in the water heater 13 and returns as condensate by a pipe line 35 to the condensate deaerating heater 16, a steam trap 36 being provided in the condensate return line 35. The flow of steam to the heating coil 34 is regulated by a thermostat valve 37 controlled by a thermostat 38 in 4the heater tank acting through a connecting cable line 39. The control connection may be other than electrical but this is shown for illustrative purposes.

Steam from the header drum 40 of the high pressure boiler 11 flows to the steam demand process equipment 14 by way of the pipe line 43 and Ithe condensate flows out by way of a pipe line 44 to the deaerating heater 16, a steam trap 45 being disposed in the line 44 to permit only the condensate to flow.

Highly purified condensate liquid from the storage -tank 17 of the deaerating heater 16 is taken off through a pipe -line 46 by a pump P1 driven by a motor M1 and delivered by a pipe line 47 to the header drum 40 of the high pressure boiler 11, a liquid level-controlled valve 48, through an electrical cable line 49 or the equivalent, regulating the operation of the motor M1.

Excess highly purified liquid condensate from the tank 17 of the deaerating heater flows by an overflow pipe line 50 to the reservoir 18. Liquid from the reservoir 18 is returned, as may be needed to maintain liquid in the tank 17, lby a pipe line 53 to a pump P2 driven by a motor M2, the pump forcing the liquid by way of a pipe line 54 to the top of the deaerating heater 16. A liquid level controlled valve 55, regulated as by a float in the tank 17, controls the operation Iof the motor M2 through an electrical cable line 56 or the equivalent.

If the reservoir 18 is full of water the excess is taken off by way of a pipe line 57 from the top of the reservoir leading to a storage tank 58 for use as highly purified deaerated water for any desired purposes.

While the general function of deaerating heaters is well known, their particular location and function in the present system has special and very beneficial functions and advantages. The feed water deaerating heater 15 serves to supply the low pressure boiler with water which has most of the corrosive gases removed. But some corrosive gases remain or are formed in the low pressure boiler and return in its steam condensate. The condensate deaerating heater 16 serves the very important function of removing substantially all of the residual corrosive gases from the condensate whereby the high pressure boiler is supplied with water which is substantially or entirely free from corrosive and scaling effects. This is especially beneficial since it is the high pressure boiler which is harmfully affected by such impurities and in which it is most difficult and expensive to eliminate the harmful effects of such impurities. The effects of some impurities in the low pressure boiler are not so serious and are much more easily overcome.

It will be seen that the high pressure boiler is always supplied with highly purified water which has: (1) passed through the softener 12; (2) been passed through the deaerating heater 15; (3) been evaporated in the low pressure boiler 10; (4) been condensed in coil 34; and (5) been passed through the second deaerating heater 16.

While one embodiment of the invention has been described for purposes of illustration, it is to be understood that there may be various embodiments and modifications within the general scope of the invention.

I claim:

1. A steam boiler system, comprising in combination, a low pressure boiler, a high pressure boiler, means for supplying source water first to the low pressure boiler, a condensate deaerating heater for the liquid supply to said high pressure boiler, a steam load unit supplied with steam from said low pressure boiler and having a steam condensate return, means for supplying condensate from the low pressure boiler to said condensate deaerating heater for the high pressure boiler, means for returning condensate from the high pressure boiler back into said condensate deaerating heater along with the condensate from the low pressure boiler, and means for supplying steam from said low pressure boiler to said condenstate deaerating heater.

2. A steam boiler installation as set forth in claim 1, which further includes in combination, a water softener for pretreating the Water supplied to the low pressure boiler a feed water deaerating heater for softened water supplied to said low pressure boiler, and means for supplying steam from said low pressure boiler to said feed water deaerating heater.

3. A steam boiler system as set forth in claim 1, which further includes in combination, a water level-controlled tank for supplying condensate water from said condensate deaerating heater to said high pressure boiler, a reservoir for holding overflow condensate from said tank, means for returning water from said reservoir to said tank, and means for drawing off excess water from said reservoir.

4. A steam boiler system as set forth in claim 2, which further includes in combination, an exchange water heater, comprising part of said steam load unit of the low pressure boiler, for heating softened water from said softener and supplying it to said feed water deaerating heater for said l-ow pressure boiler, a reservoir arranged to receive surplus excess water from said condensate deaerating heater, means for returning water from said reservoir to said condensate deaerating heater, and means for delivering excess water from said reservoir for use outside said system.

References Cited by the Examiner UNITED STATES PATENTS KENNETH W. SPRAGUE, Primary Examiner.

Claims

1. A STEAM BOILER SYSTEM, COMPRISING IN COMBINATION, A LOW PRESSURE BOILER, A HIGH PRESSURE BOILER, MEANS FOR SUPPLING SOURCE WATER FIRST TO THE LOW PRESSURE BOILER, A CONDENSATE DEAERATING HEATER FOR THE LIQUID SUPPLY TO SAID HIGH PRESSURE BOILER, A STEAM LOAD UNIT SUPPLIED WITH STEAM FROM SAID LOW PRESSURE BOILER AND HAVING A STEAM CONDENSATE RETURN, MEANS FOR SUPPLYING CONDENSATE FROM THE LOW PRESSURE BOILER TO SAID CONDENSATER DEAERATING HEATER FOR THE HIGH PRESSURE BOILER, MEANS FOR RETURNING CONDENSATE FROM THE HIGH PRESSURE BOILER BACK INTO SAID CONDENSATE DEAERATING HEATER ALONG WITH THE CONDENSATE FROM THE LOW PRESSURE BOILER, AND MEANS FOR SUPPLYING STEAM FROM SAID LOW PRESSURE BOILER TO SAID CONDENSTATE DEAERATING HEATER.