US3630275A

US3630275A - Apparatus for condensing steam

Info

Publication number: US3630275A
Application number: US785674A
Authority: US
Inventors: Adrian A Beaulieu; James L Mckenney; James W Megley; Lawrence M Munroe
Original assignee: Beaulieu Munroe Corp
Current assignee: DRC Inc A CORP OF RI; MEGATHERM Inc A RI CORP; Beaulieu Munroe Corp
Priority date: 1965-10-19
Filing date: 1968-12-20
Publication date: 1971-12-28
Anticipated expiration: 1988-12-28

Abstract

Apparatus for condensing steam comprising an elongated chamber, said chamber having an ingress and an egress opening, and a spray tube having a plurality of apertures therein extending into said chamber in concentricity therewith from one end thereof whereby liquid entering said tube is sprayed outwardly therefrom into the chamber.

Description

United States Patent [72] Inventors Adrian A. Beaulieu West Bridgewater; James L. McKenney, Nor-well; James W. Megley, Milton; Lawrence M. Munroe, Dover, all of Mass.

[21 Appl. No. 785,674

[22] Filed Dec. 20, 1968 [45] Patented Dec. 28, 1971 [73] Assignee Beaulieu-Munroe Corporation Boston, Mass.

Original application Oct. 19, 1965, Ser. No. 497,961, now Patent No. 3,422,248, dated Jan. 14, 1969. Divided and this application Dec. 20, 1968, Ser. No. 785,674

[54] APPARATUS FOR CONDENSING STEAM 2 Claims, 3 Drawing Figs.

[52] US. CL... 165/154 [51] Int. Cl F28d 7/10 [50] Field of Search 165/142,

[56] References Cited UNITED STATES PATENTS 1,371,250 3/1921 Larkworthy 261/161 1,726,020 8/1929 Garvey 165/142 1,738,914 12/1929 Mott 165/142 2,016,003 10/1935 Gantvoort 165/115 X 2,066,190 12/1936 Swars 126/362 UX 2,106,101 l/l938 LabusetaL. 261/129X 2,109,064 2/1938 Gettelman 165/111 X 2,294,163 8/1942 Donnelly et al.... 126/362 UX 2,109,064 2/1938 Gettelman 165/111 X FORElGN PATENTS 19,576 1903 Great Britain 261/DlG. 33

Primary Examiner-Edward J. Michael AttorneyRichard B. Megley ABSTRACT: Apparatus for condensing steam comprising an elongated chamber, said chamber having an ingress and an egress opening, and a spray tube having a plurality of apertures therein extending into said chamber in concentricity therewith from one end thereof whereby liquid entering said tube is sprayed outwardly therefrom into the chamber.

PATENTEU 05628 I971 SHEET 1 [IF 2 .f. 4% w am llll Ill-rklllllllllflllnllllllllllllll Illl ll In men f0 12? florz'mz A. Beau fieu Jbmes A. Mc/(erzzzey James W. MegZeg 5 Meir Attorney 'PATENTED was 1971 SHEET 2 [IF 2 APPARATUS FOR CONDENSING STEAM This application is a division of our copending application Ser. No. 497,961, filed Oct. 19, 1965 and now U.S. Pat. 3,422,248,granted Jan. 14, 1969.

Our copending application relates to apparatus for heating a building or other structure and for providing hot water for the use of its occupants or hot water for a commercial process. The present application relates generally to apparatus for use with the apparatus of our copending application to condense steam generated therein.

The discussion to follow will be specifically directed to the use of apparatus embodying the present invention in a system for heating a dwelling house and in a system for the provision of domestic hot water. The two embodiments of the present invention employed in these two systems are intended to be merely illustrative of the invention and are not to be construed as a limitation of the applicability of the teachings thereof.

l-leretofore, the cost of heating a dwelling house electrically has been disproportionate to the cost of heating the same house by the other available energy sources. That is, although installation charges for the equipment required to heat a house electrically are comparable to or less than the installation cost of other heating means, the unit charges incurred for electrical energy to operate the equipment have been considerably in excess of the cost of other fuels. This, to a certain extent, is equally true of apparatus employed to provide domestic hot water. As a consequence, the number of dwelling houses which are electrically heated is relatively small despite other advantages such as safety and cleanliness.

The invention disclosed in our copending application provides apparatus which markedly reduces the cost of electrically heating a house and supplying domestic hot water thereto by providing means which permit the purchase of electrical energy during periods that are known as offpeak periods and the storage of this energy for use during periods at which the demand for electrical energy is high, i.e. peak periods. Electrical utilities experience periods during the day in which the demand for electricity. is substantially above the requirements at other times. In order satisfactorily to fulfill their obligation to the communities which they serve, the utilities are required to predicate their power supply capacity on the highest demand for electrical energy that can be expected at any given time during the day. For example, in the metropolitan Boston area it has been found that the period of maximum demand (peak period)'is p.m. to p.m. Accordingly, the utility servicing this area must be capable of generating sufficient electrical energy to satisfy the demand during this peak period. However, this means that the utility must operate at less than full capacity for a substantial portion of each 24-hour period. That is, in the Boston area, the utility will utilize only a fraction of its energy producing capacity in the offpeak period from 10 p.m. to 5 p.m. Thus, during offpeak periods, excess energy is available. Accordingly, most major utilities have established unit charges for electricity which are lower in the offpeak period than in the period of high demand in order to encourage additional use during this period, e.g. in the Boston area the peak rate is 1.7 /kilowatthour and the offpeak rate is approximately 1 [kilowatt-hour.

The utilization of the excess energy available during the offpeak hours is not a novel concept. indeed, skilled artisans in the field have grappled with the problem for many years in the hope of spurring the use of electricity. However, these artisans have been confronted with a myriad of pitfalls which have prevented them from providing a solution to the problem. The

primary pitfall has been in the. provision of apparatus which can utilize accumulated energy in the form of high temperature stored water to heat circulating water at relatively low. pressure to a temperature substantially below the stored water temperature by some economical means while minimizing the amount of circulating water that flashes into steam. Means must also be provided for condensing any steam formed in a manner which will not render use of the apparatus undesirable.

Accordingly, it is an object of this invention to provide apparatus for condensing steam.

It is a further and more specific object of this invention to provide novel apparatus for use with the apparatus of our copending application to condense steam and equalize temperatures therein.

To this end and in accordance with a feature of this invention there is provided apparatus for condensing steam comprising an elongated chamber, said chamber having an ingress and an egress opening, and a spray tube having a plurality of apertures therein extending into said chamber in concentricity therewith from one end thereof whereby liquid entering said tube is sprayed outwardly therefrom into the chamber.

The above and other features of the invention including various and novel details of construction and combination of parts will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope of the invention.

In the drawings:

FIG. 1 is a front elevation of apparatus having components embodying this invention;

FIG. 2 is a side view of one embodiment of this invention; and

FIG. 3 is a side view of a second embodiment of this invention.

The system illustrated in FIG. 1 is intended for use in heating a dwelling house and supplying hot water therefor. It can also be employed to heat a variety of commercial or manufacturing structures and/or to supply hot water for commercial processes. One embodiment of the present invention is most advantageously employed with the system for heating a building while a second embodiment finds most effective utilization in the hot water system. Thus, the present invention can, most readily be described by delineating utilization of the two referenced embodiments in these systems as illustrated in FIG. I.

Electrical energy is utilized to heat water in a storage tank 10 by means of a conventional emersion electric heater 11 (FIG. 1) located therein. A coil capacity of 20 kilowatts has been found adequate for the normal residence in a northern section of the U.S., e.g. Boston. The water within the storage tank 10 is heated to a maximum of 280 F. in the preferred embodiment of the apparatus. This condition would apply during the winter months when the residence must be heated and domestic hot water provided. The storage tank 10 is closed and, therefore, there is no problem of vaporization at this temperature level. The pressure within the tank 10 varies between 30 p.s.i.g. and 60 p.s.i.g. depending on the temperature level therein.

A temperature of 200 F. is normally adequate to fulfill the heating requirements and demand for domestic hot water during the summer months. Accordingly, conventional means for reducing the electrical energy intake are provided (not shown) to permit the use of the system at a 200 F. operating level during the summer period. A switch (not shown) may be provided to accomplish this end.

Domestic hot water is normally supplied to a mixing valve, as hereinafter discussed, at a temperature between 150 F. to 200 F. which in turn supplies water for domestic use at F. The standard hot water heating system uses water at approximately the 1 10 to 200 F. level depending on the type of radiation used to supply heat.

Water is normally supplied to a household at approximately 20 to S0 p.s.i.g. Hot water heating systems generally operate at approximately the 25 p.s.i.g. level but not more than 30 p.s.i.g. for safety reasons as well as equipment cost. Water at a temperature of 280 F. must be maintained at approximately 35 p.s.i.g. or it will flash into steam. Accordingly, in order to utilize the energy stored in the 280 F. water to heat a household by a hot water heating system and supply domestic hot water therefor (hereinafter referred to collectively as system water), means must be provided which precisely control the exposure of the system water to the 280 F. tank. That is, only that amount of heat can be transferred to the system water which will elevate it to a temperature level below its flash point but to a minimum temperature of 150 F. or 160 F. [f the period of exposure is too extended, the system water will be elevated to a temperature which will cause it to flash into steam, e.g. for 25 p.s.i.g. this would be 267 F. The problem is further complicated by the fact that the 280 F. level only exists in the tank during the offpeak hours and for a variable period immediately thereafter depending on the demand therefore. That is, electrical energy is purchased only during the offpeak hours. Accordingly, any heat transferred from the tank 10 during the peak hours results in a loss of heat which will not be replaced until the return of the offpeak power input. Thus, the temperature level of the tank 10 will decline during the peak period. Means must therefore be provided which control the period of exposure of the system water to be heated to an interval correlated to the exact temperature level in the tank 10 at any given time.

The discussion will now be directed specifically to the embodiment of the present invention employed with the system used for the provision of domestic hot water (referred to as the system water).

DOMESTIC HOT WATER The domestic hot water apparatus essentially comprises a pilot coil 12 and a main coil 14 which are immersed in the tank 10 and means appurtenant thereto, including the apparatus of the present invention, for selectively utilizing the main coil 14 as required by the temperature level in the tank 10. The pilot coil 12 is employed exclusively when the tank 10 is at the 280 F. level. When the temperature in the tank drops to a level where the pilot coil 12 is unable to supply system water at the 150 F. level, the main coil 14 is activated as hereinafter described. The pilot coil 12 will heat the system water to within a temperature range of 150 F. to 200 F. when the tank 10 is at the 280 F. level. The exact temperature within this range is determined by the rate of flow of system water through the system, i.e. by the amount the associated hot water faucet is opened.

The coil 12 is sized such that system water passing therethrough will be exposed to the 280 F. temperature in the tank 10 for a period sufficient to raise the temperature level thereof to within the 150 F. to 200 F. range regardless of the size of the draw. That is, the coil 12, in the preferred embodiment illustrated in the drawings, has only one tube pass. The length and diameter of the tube are determined by calculating the exposure period required to elevate tap water to a minimum temperature of 150 F. when it is exposed to the 280 F. tank water during a maximum draw. These dimensions must also be such as not to permit the system water to be elevated above the flash point during a minimum draw. The exposure period is governed by the rate of flow of the system water through the tube which is in turn predicated on the pressure level of the system water and the tube size. Thus, the tube size required can be calculated accurately once certain basic data is available. Undesirable flashing of the system water into steam can therefore be avoided when the coil 12 is in use by proper sizing thereof. That is, the range of the rate of the flow of system water drawn into the system when a demand for hot water is made is controlled such that the system water will be heated to between 150 F. and 200 F. and, thus, not allowed to flash into steam. When a minimum demand for hot water is made, the temperature of the system water will be elevated to the 200 F. level as the rate of flow is at a minimum. When a maximum demand is made, the system water will be heated to approximately the 150 F. level as a high rate of flow will prevail.

When a demand for hot water is stopped, a certain amount of system water will remain in the tube of the coil 12. That is, during a period in which the hot water faucet is open, system water will flow steadily through the system at a rate adequate to elevate the temperatu-re:thereof to a minimum temperature of 150 F. However, when the faucet is closed, the fluid pressure sustaining the flow of system water is eliminated. Flow of system water will, thus, stop with the result that a residue of system water will remain isolated in each of the elements of the system. The residue of system water in the coil 12 will be exposed to the temperature of the tank 10. If the temperature in the tank 10 is in the vicinity of the offpeak temperature of 280 F., the residue of system water will be heated to this temperature and, accordingly, will flash into steam. That is, assuming a subsequent draw is not immediately made. However, the volume of water which flashes into steam is relatively small and, therefore, flashing can be permitted without adverse effects on the system. That is, when flashing occurs, corrosive minerals are produced which are harmful to the system and, further, noise results. The flashing which occurs in the residual system water in the coil 12 is of such a small magnitude as to produce miniscule mineral deposits and no noise. It is to be noted for consideration in the later discussion relative to the coil 14 that if the system water in the coil 14 were allowed to flash into steam substantial mineral deposits would be produced as well as a noise of high volume as a result of the size of the coil 14.

When a demand for hot water is made subsequent to the flashing of residual system water into steam in the coil 12, the steam in the coil 12 enters a condensing chamber 20 wherein it is condensed into water. That is, when a subsequent demand is made for hot water, system water enters the system under pressure and forces the steam out of the coil 12 and into the condensing chamber 20 where it is condensed into water thereby preventing its introduction to or passage through the entire system as steam. The condensing chamber 20 comprises concentric inner and

outer chambers

24 and 26, respectively. Steam produced during a nonoperative period in the coil 12 enters the outer chamber 26 of the condensing chamber 20 at the upper portion thereof through the piping port 28. The steam entering the outer chamber 26 will be condensed by the volume of residual water remaining in the inner chamber 24 as a legacy of the previous draw and also by contact with the inner surface of the chamber 24. The residual system water in the inner chamber 24 is not exposed to the heating effects of the tank 10 during a nonoperative period and therefore will be at a temperature between 150 F. and 200 F. As the steam enters the chamber 26 it is exposed to the cooling effects discussed above and is condensed into water and drops to the bottom of the chamber 26. The steam is thus condensed in the condensing chamber 20 without producing any noise.

In the operation of the system during the offpeak hours when the temperature in the tank 10 is in the 280 F. range, cold water is admitted to the system though an inlet 30 when a demand for hot water is made. A controlled, variable amount of incoming cold water is admitted to a mixing valve 34 for mixing with hot system water supplied from the condensing chamber 20 at a temperature within the 150 F. to 200 F. range, as hereinafter described. The exact amount of incoming cold water admitted to the mixing valve 34 is automatically controlled by the mixing valve in response to the temperature level of the hot system water supplied to it, That is, the mixing valve admits sufficient cold water to temper the hot system water supplied at 150 F. to 200 F. to supply hot water at the tap within a range of F. to F. The mixing valve 34 is a standard commercially available valve.

The remainder of the incoming system water passes through a one-way or check valve 36, into the piping line 38, and thereafter into the coil 12 where it is exposed to the 280 F. water in the tank 10 and heated to F. to 200 F. depending upon the draw. An expansion tank 40 is provided to accommodate expansion which takes place as a result of the heating of the system water. The check valve 36 prevents the hot system water in coil 12 and piping 38 from backing up into the cold water supply. If the check valve 36 were not present, hot system water would back up and be introduced into the mixing valve 34 at the cold inlet thereby resulting in the supply of untempercd water at the hot water tap.

The incoming system water forces the steam formed by the residual system water in the coil 12 through the piping 39 into the chamber 26 where it is condensed and falls into the bottom of the chamber 26 as hot water. Thereafter, system water is fed through the coil 12, heated to 150 F. to 200 F. and then passed into the chamber 26 as hot system water. System water passes from the lower portion of the chamber 26 through an outlet 41 into piping 42 which leads to a port 46 in a mixing valve 50. The mixing valve 50 functions to mix system water supplied from the coils l2 and 14. The mixing valve 50 is inoperative until the water flowing from the chamber 26 drops below the 150 F. level. That is, as long as the coil 12 supplies water to the mixing valve 50 at 150 F. or greater, the mixing valve 50 will isolate the coil 14 and, thus, not function as a mixing valve. This situation will prevail during the offpeak hours when the temperature in the tank is at the 280 F. level. It will also prevail for a variable interval during the peak period. That is, the coil 12 will supply water between 150 and 200 F. when the temperature of the water in the tank 10 is in the 240 to 280 F. range. Accordingly, the mixing valve 50 will not normally be activated during the peak period until the temperature of the water in the tank 10 drops below the 240 F. level. This is determined by the amount of usage during the initial portion of the peak period and by the rate of flow for a particular draw during the period of declination. The mixing valve 50 is a standard commercially available valve.

Accordingly, in operation of the system during the offpeak period, and a variable portion of the peak period, system water enters the mixing valve 50 and passes directly therethrough into piping 52. That is, the valve seat associated with the port 54 of the mixing valve 50 is seated whereby to prevent passage of system water from the coil 14 to the mixing valve 50. A one-way or check valve 56 in the line 60 leading from a point in the line 39 adjacent the coil 12 to the coil 14 permits the flow of system water from coil 12 to coil 14 only. Thus, the portion of the system associated with the coil 14 is a closed system when the port 54 of the mixing valve 50 is closed. Ergo, when the port 54 is closed and the temperature in the tank 10 is in the 280 F. range, pressure is built up to the 35 to 60 p.s.i.g. level within the above defined closed portion of the system. That is, since the system is closed, a pressure buildup is possible within the system correlated to the temperature in the tank 10 whereby to prevent the residual system water in the closed portion of the system from flashing into steam. This buildup in pressure in front of the one-way valve 56 prevents the valve 56 from being opened by system water which is being fed through the system at approximately p.s.i.g. Thus, when the port 54 is closed, no system water flows in or out of the closed portion of the system associated with the coil 14.

The system water thereafter flows through the piping 52 into a tube 70 in the upper end of the inner chamber 24 of the condensing chamber 20, see particularly FIG. 2. The tube 70 extends downwardly from the top of the chamber 24 into the chamber and has a plurality of openings randomly formed therein. A portion of the system water passing through the tube 70 is forced through the openings and is sprayed onto the dividing member common to the inner and

outer chambers

24 and 26, respectively. The dividing member is thus tempered to ensure the condensation of any steam emanating from the coil 12 which enters the chamber 26. The spray also functions to condense the condensation of any steam that might have been leaked into the chamber 26 during a period of no demand. Likewise, steam leaked into the mixing valve 50 through the closed port 54 due to wear of the valve seat will be condensed when it is forced out through the holes. The condensing chamber also serves to speed the response of the system to a draw as a result of the residue of heated water therein. This is particularly important when a fast draw is made.

The system water falls to the lower portion of the chamber 24 from the tube 70 and passes therefrom through the piping 76 to the mixing valve 34 wherein it is mixed with a predetermined, measured flow of incoming water to supply process hot water at a desired temperature level.

As noted above, during the peak hours when the source of electric energy for heating the water in the tank 10 is shutoff, the temperature of the water in the tank 10 gradually will be lowered as a result of demands thereon both for the supply of hot water and for heat. When the temperature in the tank 10 has been lowered to a point where it can no longer heat the system water passing through the coil 12 to the 150 F. level (approximately at 240 F.), the port 54 of the mixing valve 50 will be automatically opened slightly to permit limited flow of hot water from the coil 14 into the mixing valve 50. The system associated with the coil 14 is, thus, no longer closed. Accordingly, since the pressure built up therein has been lowered in response to the temperature drop and vented into the mixing valve 50, a portion of the system water flowing through the line 39 enters the line 60, passes through the check valve 56 and is exposed to the coil 14. However, the temperature in the tank 10 has been lowered and, thus, the system water will not flash into steam as it traverses the coil 14. This is likewise true of the residual system water in the closed system associated with the coil 14. That is, at the time the mixing valve is opened, the temperature of this residual water has been lowered to a point where it will not flash into steam as a result of the decline in temperature of the tank 10 water.

The mixing valve 50 determines the amount of system water flowing through the coil 14 by automatically adjusting the position of the valve seat associated with the port 54. That is, the mixing valve 50 automatically adjusts the amount of system water flowing through the port 54 in response to the temperature of the system water supplied through the piping 42 from the coil 12. The valve seat associated with the flow of system water through the port 46 is simultaneously closed in proportion to the degree which the port 54 is opened. The amount of system water flowing through the coil 14 is controlled in this way.

The discussion will now be directed to an embodiment of the present invention particularly adapted for use with apparatus for heating a household.

HEATING SYSTEM The heating apparatus essentially comprises a heating coil immersed in the tank 10 and a condensing chamber 92. The rate of flow within the process hot water system described above generally varies between 5 and 8 gallons per minute. Accordingly, as discussed above, the coil 12 must be used during the offpeak hours when the temperature of the tank 10 is in the 280 F. range in order to prevent continuous flashing of the system water into steam. That is, for a rate of flow of 5 gallons, the system water would be elevated above its flash point if it were exposed to the 280 F. tank 10 temperature for the period required to pass through the coil 14. The rate of flow of system water through the standard household hot water heating system is between 10 and 20 gallons per minute. Thus, the size of the coil 90 may be greater than that of the coil 12. In fact, the size of the coil 90 is approximately that of the coil 14.

The condensing chamber 92, see particularly FIG. 3, comprises a heat reserve chamber 94, a condensing tube 96, and a spray tube 98. The condensing chamber 92 serves as a conduit through which return system water is passed for introduction to a flow chamber thereafter to be directed either to the coil 90 or back into the supply line 102 through a three-way valve 104, as hereinafter described with greater specificity. Return system water enters the condensing chamber 92 through a piping port 106 and passes directly into the heat reserve chamber 94. Heated system water which has passed through the coil 90 enters the condensing chamber 92 through piping 110 which feeds the hot system water into the upper end of the condensing tube 96. The heated system water coming from the coil 90 passes through the condensing tube 96 and out through the three-way valve 104 to the supply line 102 when the valve 104 is set to permit such passage, as hereinafter described in detail. During a part of the cycle of operation of the system illustrated in FIG. 1 and described hereafter, a portion of the return system water entering the chamber 94 is forced up into the spray tube 98. The spray tube 98 extends upwardly into the condensing tube 96 and comprises a cylindrical tube having a closed upper end and a plurality of apertures 99 formed in the sides thereof. Accordingly, return system water forced into the spray tube 98 is sprayed outwardly into the condensing tube 96 to be commingled with the heated system water flowing from the coil 90. The primary function of the spray is to condense any steam formed in the coil 90 during a period of nonoperation and to temper system water flowing through the condensing tube 96, as hereinafter described.

An appreciation of the novel structure of the condensing chamber 92 is most readily obtained from a detailed discussion of its operation in the system illustrated in FIG. 1. It is to be initially and clearly understood that a household heating system is distinguished from a domestic hot water system in that the former is a closed system. That is, whereas the domestic hot water system supplies water for consumption and continually is supplied with new system water, a household heating system recirculates the same system water without having any source of replenishment. Accordingly, the apparatus illustrated in FIG. 1 together with the piping used to convey the hot system water through the house comprises a closed system. The significance of this will be advanced in the discussion to follow.

In order to facilitate an orderly presentation, the discussion will begin at a point in the operative cycle where a demand for heat just has been made. An demand is initiated by a standard thermostat (not shown) which may be located at any convenient location in the house and set for any desired temperature level in the house. The thermostat actuates an Aquastat 120 which controls the temperature of the system water within a prescribed range. For example, if the thermostat were set for 70 F., the aquastat would be actuated by the thermostat when the temperature in the house dropped below 70 F. The actuated Aquastat would react to effect heating of the system water if the temperature of the system water was below 150 F., for example. Once actuated, however, the Aquastat would remain actuated until the temperature of the system water was elevated to the 170 F. level in this particular example. The prescribed range for the Aquastat in this example is, thus, 150 F. to 170 F. The reason for this is that l50 F. system water can maintain the temperature of a house at the desired 70 F. level or elevate the temperature to this level within a given acceptable number of recirculations through the system. System water at 170 F. can elevate the temperature to 70 F. faster but not significantly so. However, the Aquastat is designed to continue in operation until the temperature of the system water is raised to 170 F. once it is actuated to minimize the number of times the coil 90 is utilized to maintain a given temperature level. Demand for heat by the thermostat (not shown) also actuates circulators (not shown) which initiate the circulation of system water within the system.

When the temperature of the system water is unable to satisfy the demand for heat registered on the thermostat; e.g., when the temperature of the system water is below 150 F. in the above example, the Aquastat actuates the three-way valve 104 to open the piping port 124 and close the piping port 126. Thus, the valve 104 permits the flow of system water from the condensing tube 96 to the supply line 102 but not from. the flow chamber 100 to the supply line 102.

Return system water entering the heat reserve chamber 94 passes therefrom through piping 128 into the flow chamber 100. When the valve 104 is seated at the port 126, as discussed above, system water is forced into a bleed tube 132 which directs the system water through piping 134 to the coil 90. The bleed tube 132 is an elongated tube having a plurality of apertures 133 therein which depends downwardly into the flow chamber 100 from the upper portion thereof. The lower end of the bleed tube 132 is open. System water entering the flow chamber 100 when the piping port 126 is closed, enters the bleed tube 132 through the above-described apertures 133 and through the lower, open end thereof for passage into the coil 90.

The initial flow of system water into the coil after a period of nonoperation forces steam formed in the coil "90, as hereinafter described in detail, into the line 110 leading to the condensing tube 96. When the steam enters the condensing tube 96, it is exposed to the spray of return water emanating from the spray tube 98, as discussed above. The steam is thus condensed without producing audible noise and flows to the base of the condensing tube 96 and into the supply line 102 through the valve 104. The system water entering the coil 90 is elevated in temperature and thereafter passes into the condensing tube 96 wherein the spray of return water from the tube 98 is mixed therewith. The system water within the closed system is thus gradually elevated to the level required by the Aquastat. That is, the heated water within the closed system is thus gradually elevated to the level required by the Aquastat. That is, the heated water passing from the coil 90 is tempered by the portion of the return water which is introduced to it through the spray tube 98. If the system water were not tempered in the condensing tube, the Aquastat would be prematurely actuated before all the system water was within or close to the prescribed level. The temperature of return water passing through the heat reserve chamber 94 is elevated by heat transferred thereto from the heated system water within the condensing tube 96. This transfer of heat also functions to ensure a progressive, gradual elevation of the temperature of the system water. Recirculation of system water through the heat reserve chamber 94, flow chamber 100, coil 90, condensing tube 96 into the supply line 102 continues in the manner described above until the temperature setting on the Aquastat is satisfied.

When the upper level of the temperature range set on the Aquastat is reached; e.g. 170 F. in the above example, the Aquastat actuates the three-way valve 104 to close the piping port 124 and open the piping port 126. The valve 104 will thereafter permit the flow of system water to the supply line 102 from the flow chamber but not from the condensing tube 96. As a result, flow of system water from the coil 90 to the condensing tube 96 will cease due to the build up of pressure behind the piping port 124 of the valve 104. Residual system water will thus stand stagnant in the condensing tube 96 and coil 90. The residual system water in the coil 90 continuously will be exposed to the temperature within the tank 10 and, accordingly, will be elevated in temperature to a level corresponding to the temperature within the tank 10 if the interval of no demand for heat is sufficiently prolonged. If the temperature within the tank 10 is above the flash point temperature of the system water, certain of the system water within the coil 90 will flash into steam. That is, the residual system water in the coil 90 nearest the outlet piping will reach the flash point first as it will have been exposed to the temperature in the tank 10 for the longest period. The flashing of this system water into steam produces a buildup in pressure which is transmitted to the residual system water entrapped in the condensing tube 96. Since the condensing tube 96 is closed by the valve 104 there is no vent for the pressure buildup except into the chamber 100. The expansion of the system water when it flashes into steam and the corresponding buildup in pressure will force a portion of the residual system water initially entrapped in the coil 90 out of the coil through the bleed tube 132 before it flashes into steam. Thus, the total volume of system water entrapped in the coil 90 will not flash into steam. The pressure buildup within the coil 90 will be transmitted to the remainder of the system and compensated for in an expansion tank (not shown). Any leakage of steam from the coil 90 into the bleed tube 132 prior to the equation of pressure in the system will be condensed as it sprays out through the apertures in the sides thereof. Once the pressure in the system appurtenant to the coil 90 reaches the pressure in the coil 90, there will be no further leakage of steam. Further, the pressure within the condensing tube 96 will prevent the passage of water thereto through the spray tube 98. The tot al pressure increase is approximately p.s.i.g.

As noted above, when the temperature requirement of the Aquastat is? satisfied, the valve 104 will thereafter permit system water to flow to the supply line 102 from the flow chamber 100 but not from the condensing tube 96. The satisfaction of the temperature requirement of the aquastat does not necessarily mean that the house has been elevated to the desired temperature level, i.e., that the thermostat has been satisfied. If the Aquastat has been satisfied but not the thermostat, the circulator will continue to circulate the system water. However, the return water entering the heat reserve chamber 94 will pass to the flow chamber 100 and thereafter through the piping port 126 to the supply line 102. The circulating system water is prevented from entering the coil 90 and condensing tube 96 as a result of the buildup in pressure hehind the piping port 124. The system water will be circulated in the manner just described until sufficient heat has been transferred from the circulating system water to the house to satisfy the temperature requirement registered on the thermostat. When the thermostat is satisfied, the circulators will be stopped and the system water will remain stagnant in the system.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for condensing steam formed in a system for heating water comprising concentric inner and outer chambers, a dividing member common to said inner and outer chambers and defining said inner chamber, ingress means at an upper end of said outer chamber through which steam is introduced to said outer chamber to be condensed therein by contact with said dividing member and by residual system water in said outer chamber, a spray tube having a plurality of apertures randomly formed therein extending centrally into the upper portion of the inner chamber in concentricity therewith from the upper end thereof whereby system water entering said tube is sprayed outwardly therefrom onto the dividing member to temper said dividing member and whereby steam introduced thereto is forced outwardly into said inner chamber and thereby condensed.

2. Apparatus for condensing steam formed in a system for heating water and for tempering heated system water entering the apparatus from heating means by commingling said heated system water with return system water entering said apparatus comprising a closed heated reserve chamber having an ingress opening for admitting return system water under pressure, an elongated condensing tube a portion of which is housed within said heat reserve chamber, a spray tube extending into said condensing chamber in concentricity therewith from an end portion thereof housed within said heat reserve chamber, said spray tube having a plurality of apertures therein and having one end thereof communicating with said heat reserve chamber whereby return system water entering said heat reserve chamber under pressure is forced into the spray tube and sprayed outwardly therefrom into the condensing tube to temper system water and condense steam therein.

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