Fluid flow control system

Disclosed is a dual output, pressure responsive, adjustable, fluid flow control system. It includes first and second flow networks coupled in parallel flow communication, the networks each have first and second flow paths, and the first flow path of flow networks has an adjustable flow control valve for regulating the flow therethrough. Similarly, the second flow path of said networks has a pressure responsive valve disposed therein for maintaining substantially constant flow therethrough with variations in fluid flow pressure therein. Also included are feed means for supplying fluid to said flow networks, and means for receiving fluid from said fluid flow networks, as well as means for engaging and disengaging the second flow network to said fluid supply means for selectively permitting the flow therethrough and facilitating a dual flow output from the system.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to vapor generators and, more particularly, 
to a vapor generator fluid flow control system, permitting controlled 
fuel, air and water flow and pressure regulation. 
2. History of the Prior Art 
Vapor generators of the kind in which a fuel-air mixture is combusted in 
the direct presence of feed water to produce a useful mixture of steam and 
non-condensibles are known. Such vapor generators are shown in U.S. Pat. 
No. 4,211,071 issued to the assignee of the present invention. In 
accordance with that invention, a vapor generator is provided in which 
several interrelated means are employed to improve the quality of 
combustion in the generator so that a product steam substantially free of 
carbon monoxide results. In effecting this result, means are provided for 
dividing the air feed into two parts which are both delivered to the 
generator for combustion. Such methods and apparatus are effective in 
producing a well-mixed stoichiometric mixture of fuel and air to provide 
completeness of combustion and reducing production of carbon monoxide to 
extremely low levels. Such an accomplishment is a marked advance over the 
prior art and illustrates the emphasis placed on controlled flow rates and 
mixture conditions. 
The prior art is also replete with apparatus manifesting high temperature 
product vapor having high carbon monoxide content. Such conditions are 
objectionable for many applications and dangerous for some of them. High 
carbon monoxide production is traceable to incomplete combustion. This is, 
in turn, traceable in part to difficulties in maintaining a stable lean 
flame and, in part, to excessive quenching of the flame through direct 
radiation and convective contact between the flame and the feed water. 
Once a stoichiometric mixture is obtained, it is, therefore, necessary to 
maintain the combustion level without varying any of the three major 
constituents of fuel, air, or water. Variations would affect the 
combustion and the carbon monoxide production therefrom. 
Other problems occur in certain ones of the prior art vapor generators when 
they are operated at low pressures. Conventionally, as shown in U.S. Pat. 
No. 4,288,978, a vapor generator may be especially adapted for low 
pressure operation by the provision of certain features such as a pilot 
burner for striking a stable flame. It may be seen that low pressure 
operation, likewise, requires a specific reduction in the air, fuel and 
water input for a low volume output from the vapor generator. 
Disproportionate variances in any of the three constituents will seriously 
affect the combustion level and the resulting heat and vapor content of 
the downstream product. 
Few prior art systems effectively address dual output vapor generator 
operation. The ability to fine tune the fuel, air and water flow for a 
single vapor generator output is critical enough. Once this critical 
equilibrium is reached, it is tantamount to starting over to vary the 
generator operation to another flow. Varying the generator volume 
necessitates adjustment in the air, fuel and water flow rates which will 
directly affect both the heat and the water vapor level of the combustion 
products. When such generators are used in industrial applications 
necessitating precise control of heat and vapor, these variations are not 
tolerable. One such application is the curing of concrete where the 
temperature and moisture level of the vapor products have a direct effect 
on the curing process and resulting structural condition of the cast 
product. 
The use of steam for concrete curing is not novel in and of itself. Steam 
has been produced from conventional boilers for such methods and 
processes, but the cost of a boiler operation is much higher than that of 
a vapor generator type device. Moreover, the temperature and vapor level 
of the steam product can be more closely controlled than with a 
conventional boiler. Moreover, super heated vapor can be provided for 
specific types of aggregate to be cured. The flexibility of the vapor 
generator also permits substantially instantaneous operation as compared 
to the threshold period for a boiler method. The obvious disadvantage is 
the substantially single flow rate afforded by most conventional vapor 
generators. Since any number of kilns may be run at one time for 
particular production schedules, excess vapor from a single flow rate 
vapor generator system would, thereby, be wasted. 
Conventional techniques for varying the output of standard vapor generators 
includes reducing the rate of combustion and water flow while maintaining 
a constant air flow rate. The advantage of such a system is simplicity and 
cost in that reliable variations in air flow rates have been, to date, 
difficult to attain. The paramount disadvantage to the continuous air flow 
volume is the excess air ingressing into the kiln and the adverse effects 
to the curing process which affects the ultimate humidity level within the 
kiln and imparts non-uniform cooling characteristics. Variations in the 
air flow volume have, to date, been addressed by multiple speed blowers 
and throttle systems which either decrease the air intake to the blower or 
exhaust therefrom. Unfortunately, the relatively large motors and blower 
units necessary for vapor generator volumes generate large amounts of heat 
which the air volume dissipates. When the air volume is throttled for 
constant motor speed, heat dissipation is inhibited and variations in flow 
rate result as well as having degenerative effects on the motor and the 
blower unit. The obvious alternative to such flow problems is a multiple 
speed motor, but the cost and availability for such systems are generally 
disproportionate to the vapor generator construction. 
Dual output vapor generator applications also require dual flow feedwater 
systems which may be accurately set in preselected flow configurations as 
well as precisely maintained. Precise fluid flow is an integral element of 
the aforesaid combustion efficiency particularly in stoichiometric 
mixtures. The primary area of fluid flow consideration in such vapor 
generator systems is in the water flow controlling network. Prior art flow 
control devices though capable of preselect flow volumes are generally not 
sensitive to variations in flow pressure which affects the flow volume. 
It would be an advantage therefore to overcome the problems of the prior 
art by providing a variable output vapor generator having a constant 
volume fluid flow system which affords automatic operation between high 
and low fluid flow rates and which is sensitive to fluctuations in fluid 
flow pressure. One approach to dual output vapor generators and a 
discussion of prior art problems associated therewith is discussed in 
co-pending U.S. patent application Ser. No. 554,780 assigned to the 
assignee of the present invention. The method and apparatus of the present 
invention comprises an advanced system overcoming the problems set forth 
above by providing a combination of a pressure responsive valve and fine 
adjustment valve in parallel flow communication. This parallel flow system 
is itself aligned in parallel flow communication with a second matching 
system adapted for selective actuation for high and low volume operation. 
In this manner both the high volume and low volume flow rates within the 
water flow system of a vapor generator may be pre-adjusted for automatic 
actuation as needed by demand conditions. This has been done in a 
configuration facilitating automatic temperature control and which is 
pressure sensitive for accurate volumetric control without adversely 
affecting the efficiency of the generator system. 
SUMMARY OF THE INVENTION 
The present invention pertains to vapor generators incorporating a dual 
fluid flow control actuation system which is pressure responsive in 
conjunction with minor flow adjustability. In one aspect, the present 
invention includes a dual output, pressure responsive, adjustable, fluid 
flow control system which comprises first and second flow networks coupled 
in parallel flow communication. The first and second flow networks each 
comprise first and second flow paths which comprise an adjustable flow 
control valve for regulating the flow therethrough. The second flow path 
of the networks comprises a pressure responsive valve disposed therein for 
maintaining substantially constant flow therethrough with variations in 
fluid flow pressure. There is also shown means for supplying water to and 
means for receiving water from the fluid flow networks and means for 
engaging and disengaging the second flow network to the first flow network 
for selectively permitting the flow therethrough. 
In another aspect, the present invention includes an improved water control 
system for vapor generators of the type wherein water is channeled to a 
vapor generator in at least two flow volumes selectively regulatable in 
conjunction with the operation of the vapor generator and at predefined 
flow rates, wherein the improvement comprises each of the flow channels 
including first and second flow paths coupled in parallel flow 
communication. The first flow path has disposed therein an adjustable flow 
valve for the setting of fluid flow volume therethrough. The second flow 
path has disposed therein a pressure responsive flow valve adapted for 
controlling the rate of flow therethrough in response to the pressure of 
fluid thereupon. In this manner, perturbations in fluid flow pressure are 
compensated within the second flow line for providing a generally constant 
fluid flow rate from the system. 
In yet another aspect, the invention includes an improved method of 
controlling the flow of water to a vapor generator of the type wherein a 
first flow volume is regulated for a first vapor generation operation and 
a second greater flow volume is utilized for a second vapor generator 
operation. The water flow regulation is provided through a flow network 
incorporating adjustable flow valves for preselect flow. The improvement 
comprises the provision of first and second flow networks to the vapor 
generator, each in parallel flow relationship. Each flow network includes 
an adjustable flow control valve in a first path of the flow network. 
There is also provided a pressure responsive valve in the second flow path 
of the flow networks. The control valves of the first flow paths of the 
flow networks are set for the requisite flow volumes of the dual 
operational flow and perturbations regulated in fluid flow pressure within 
the flow paths with the pressure responsive flow valves. 
In another aspect of the present invention there is shown a system for 
regulating fluid flow to a vapor generator for preselect, multi-phase 
operation thereof. The system comprises at least two flow networks adapted 
for providing the flow of fluid to the vapor generator in preselect flow 
volumes. Each of the flow networks comprises first and second flow 
conduits disposed in parallel flow relationship for simultaneously 
carrying fluid flow therethrough and to the vapor generator. There is also 
provided an adjustable flow valve disposed within the first flow conduit 
for permitting the setting of a preselect flow volume and a pressure 
responsive flow valve disposed within the second flow conduit for varying 
fluid flow therethrough in response to pressure perturbations within the 
fluid flow path of a magnitude for maintaining the fluid flow from the 
flow network relatively constant. 
In yet another aspect of the present invention the fluid flow network is 
comprised of a supply water feed network, the vapor generator being set 
for dual flow operation. The system further includes a valve disposed 
between the first and second flow networks for selectively permitting the 
flow through the second flow network in response to high volume operation 
of the vapor generator and the valve between the first and second flow 
networks comprises a remotely actuatable valve. The pressure responsive 
valve comprises a first fixed orifice and a second flexible orifice 
contiguous thereto adapted for flexing in response to fluid flow pressure 
flowing thereagainst. 
A further aspect of the present invention includes an improved water 
control system for vapor generators of the type wherein water is channeled 
to a vapor generator in at least two flow volumes selectively regulatable 
in conjunction with the operation of the vapor generator and at predefined 
flow rates for establishing a select vapor generator discharge 
temperature. The improvement comprises each of the flow channels including 
first and second flow paths coupled in parallel flow communication. The 
first flow path has disposed therein an adjustable flow valve for setting 
the fluid flow volume therethrough. The second flow path has disposed 
therein a pressure responsive flow valve adapted for controlling the rate 
of flow therethrough in response to the pressure fluid thereupon. In this 
manner perturbations in fluid flow pressure are compensated with the 
second flow line for providing a generally constant fluid flow rate from 
the system. Moreover, a second parallel flow path system comprising both 
an adjustable flow valve and a pressure responsive flow valve is provided 
in a generally parallel flow relationship. Flow through the first and 
second adjustable flow control valves is controlled by a remotely 
actuatable flow valve disposed upstream thereof and actuatable in response 
to the temperature condition of the discharge of the vapor generator.

DETAILED DESCRIPTION 
Referring first to FIG. 1, there is shown a dual output vapor generator 
system 10 constructed in accordance with the principles of the present 
invention. The primary component of the system 10 is the vaporizer proper, 
or main combustion chamber 11. Chamber 11 is preferably an upright, closed 
ended, elongated cylinder adapted to enclose the bulk of the flame 
generated in accordance with the invention. To the lower end of chamber 11 
is connected a product exit line, or conduit 12, in which is mounted a 
back pressure control valve 13 or the like, which is shown quite 
diagrammatically. As will be defined below, the vaporizer 11 operates in 
conjunction with a dual input flow network of air, fuel and water to 
provide a carefully regulated dual output system. 
Still referring to FIG. 1, the chamber 11 comprises a cylindrical outer 
wall 19 and closed ends 14 and 15. Provision is made for the delivery of 
feed water to the interior of the main combustion chamber. These 
provisions include water inlet lines 16, and internal cylindrical wall or 
tube 17. Tube 17 is attached to the bottom end 14 and terminates in a 
relatively small distance short of the top end 15. An annular space 18 is 
thus established between the walls 19 and 17 extending over substantially 
the full height of the chamber 11. It is to be understood that the 
vaporizer 11 is set forth and described herein for purposes of 
illustration and other embodiments of vaporizer units may be utilized in 
accordance with the principles of the present invention for dual output 
vapor generation. 
In operation of the select vaporizer 11, feed water is delivered into the 
annular space 18 through the inlet line 16. The water cools the unit and 
is warmed as it rises through the annular space, or jacket 18. The water 
then spills over the top edge of the tube 17, and flows down its inner 
wall. As will be explained more fully here below, during the first part of 
the downward travel, the water absorbs heat conductively from a shielded 
portion of the flame. During the final part of its downward flow, the feed 
water is in direct radiative and convective contact with part of the 
flame, and is vaporized thereby to form steam and becomes part of the 
product stream leaving chamber 11 via conduit 12. 
The fuel and air delivery system of the invention is designated generally 
as 20. It includes an air compressor 21, having an air filter 22, both of 
which are shown diagrammatically. Various types of compressors having 
suitable output pressure and delivery rates may be employed. Such 
compressors are, however, generally comprised of relatively large motors 
and blowers as necessitated for conventional commercial applications. 
Motors of the forty horsepower variety are not uncommon in commercial 
applications of vapor generation units, and one aspect of the present 
invention is the consideration of such motor and blower units and the 
operation thereof. 
The compressed air issuing from the compressor 21 enters conduit 23 on its 
way to vaporizer chamber 11. In accordance with the principles of the 
present invention, as more fully set forth in copending application Ser. 
No. 554,780, the compressed air flowing through conduit 23 may be vented 
through a second conduit 24. This aspect controls the volume of air 
permitted to ingress the vaporizer chamber 11. The venting control mode of 
the invention permits the compressor 21 to operate at a uniform speed 
although the output of the system 10 may be switched from a high to a low 
level. This flow rate change may also be effected without the conventional 
adverse effects of alteration of air flow rates. 
Conventional techniques for altering the flow of air to the vaporizer 
chamber 11 includes the provision of a two-speed compressor motor and/or 
throttling devices for controlling either the input or output of 
compressed air. As stated above, numerous disadvantages are associated 
with such systems due to the fact that heat dissipation is a primary 
consideration in high powered conventional compressors. The invention 
overcomes this operational limitation by permitting the system 10 to 
operate without the deleterious effects of throttling systems and/or the 
complex and expensive multi-speed motor networks. 
The compressed air stream in conduit 23 of the invention may be divided 
into two streams at juncture 26. The primary stream continues on through 
conduit 25 into a silencing unit 28 which functions much like a muffler to 
reduce the noise level issuing from the system 20. Downstream of the 
silencer 28, an orifice plate, or valve 27 may be provided for purposes of 
pressure regulation and mixing with the fuel input network. A secondary 
orifice plate and valve assembly (not shown) may also be incorporated 
where necessary for the dual operation modes, although it has been found 
effective to operate with the single orifice configuration shown herein. 
Immediately downstream of orifice plate 27 in the main air flow and mixing 
conduit 25, there is provided a fuel inlet 28. Flow in conduit 25 just 
downstream of the orifice plate 27 is quite turbulent, and it is desirable 
to introduce the fuel at that point to initiate thorough and intimate 
mixing of the fuel and air. Furthermore, it is preferred that mixing 
conduit 25 be fairly long in order to provide a full opportunity for 
thorough mixing of the air and fuel stream before it reaches the 
combustion chamber 11. Mixing is also enhanced by the directional change 
in the main flow conduit 25 at the bend or elbow 29. The diameter of the 
mixing conduit 25 is selected in view of the desired maximum flow rate so 
that the lineal velocity of mixture flowing therethrough is substantially 
equal to or slightly greater than, the flame propagation speed. In this 
manner the flame established and maintained in the combustion chamber will 
not migrate back up into the conduit 25 or its bend 29. For example, with 
the designed fuel flow of 17 cubic feet per minute, mixed with a 
stoichiometric quantity of air, a nominal conduit diameter of about two 
inches has been shown to be satisfactory. 
The structure and operation of the combustion chamber 11 is shown 
diagrammatically herein and may be modified for various applications. The 
specific embodiment of the combustion chamber 11 of the present invention 
as depicted in FIG. 1 includes a pre-combustion chamber 30 of the type set 
forth in U.S. Pat. No. 4,228,978 assigned to the assignee of the present 
invention. A branch or auxillary air conduit of the type shown in the 
aforesaid patent is not presented herein for purposes of clarity and may 
or may not be utilized in conjunction with the present invention. What is 
shown is a structure comprising a cylindrical housing 31, somewhat larger 
in diameter than opening 32 in the upper end 15 of chamber 11. Housing 31 
is attached to upper end 15 by means of flange 33. The upper end of 
housing 31 is closed by plate 34 and a flame enclosing skirt or shield 39 
depends downwardly therefrom. A cylindrical annular space 36 is thus 
defined by a skirt 39 and housing 31. Conduit 25 is attached to the top of 
the pre-combustion chamber to deliver a fuel-air mixture into the 
cylindrical space within shield 39. 
In the present embodiment of the vaporizing combustion chamber 11, a second 
flame enclosing shield or skirt 38 is mounted on top end 15 to depend 
downwardly from opening 32. Upwardly therefrom, and extending through 
cylindrical shield 39, is spark plug 37 for igniting the fuel-air mixture 
and creating the combustion flame 40. A pilot flame as shown in the 
aforementioned references may also be used in lieu of said plug. With the 
foregoing detailed description of one embodiment of apparatus of the 
present invention in hand, an outline of its mode of operation can be 
given with reference to that description. The system 10 of FIG. 1 
illustrates a dual output vapor generator system which will automatically 
operate at either a high and low flow rate. As can be seen from the 
foregoing discussion, three primary input streams are involved: fuel gas, 
combustion supporting gas (preferably air from an electrically driven 
blower or compressor), and water. There are thus three primary points of 
control: fuel valve 78, air compressor motor 79 (and particularly its 
on/off mechanism), and the main water valve solenoid 80. During start up, 
the spark plug 37 is also actuated to produce a pilot spark as an 
additional point of control. 
Addressing now the fuel flow system 82, there is shown a parallel flow 
network upstream of the fuel inlet jet 28. The system 82 comprises a main 
fuel flow conduit 83 regulated by needle valve 84 and a by-pass conduit 85 
through which the flow is controlled by solenoid valve 86 and needle valve 
87. Fuel is permitted to flow through system 82 after actuation of the 
solenoid valve 78. With solenoid valve 86 in the closed position, all fuel 
flow extends through needle valve 84 to flow jet 28. Needle valve 84 is 
set for the low output operation of the system 10. When high output is 
demanded, solenoid valve 86 is opened to allow concurrent flow through 
by-pass channel or conduit 85 controlled by needle valve 87 whereby the 
fuel flow is increased a preselected amount. The present invention 
addresses the flow control of water input stream as set forth below. 
Still referring to FIG. 1, water flow system 90 comprises a main flow 
conduit including main flow line 91 which is divided into control flow 
line 92 and adjustable flow line 93 coupled into feed line 94 and 
connected to water input line 16. Control line 92 includes a select 
pressure responsive valve 95. The pressure responsive valve comprises a 
flow control valve having a flexible orifice or the like that varies its 
area inversely with the pressure so that a constant flow rate is 
maintained for fluids passing therethrough. A variety of such pressure 
responsive devices are taught in the prior art and one such device is 
available from Dole Energy Controls. The flow control valve of this 
variety includes a first orifice of rigid construction disposed contiguous 
a second flexible orifice, the flexing of which under pressure reduces the 
orifice size. In this manner variations in pressure are manifest in 
changes in orifice dimension affording a variation in the size of the 
fluid flow path. This permits a constant flow of fluid through the flow 
control valve for variations in pressure within a preselect range. 
Referring now to FIG. 2, there is shown an enlarged diagrammatical view of 
the water flow control network of FIG. 1. Adjustment line 93 incorporates 
the adjustable valve 96 for permitting precise regulation of flow 
therethrough in conjunction with flow through line 92. A remotely 
actuatable solenoid valve 97 is likewise provided in a parallel flow 
network 98 for selectively permitting flow therethrough. Flow network 98 
is provided for permitting parallel flow patterns when valve 97 is open in 
a similar fashion to that through primary flow conduit 91. A first control 
flow path 100 is thus provided with a pressure responsive valve 101 with 
an adjustable flow conduit 102 controlled by adjustable valve 103. Flow 
lines 100 and 102 combine in secondary output line 104 and merge with flow 
from conduit 94 to pass through input line 16. 
Still referring to FIG. 2, the water flow network of this particular 
embodiment comprises a system 90 diagrammatically shown as 4 flow paths 
comprised of conduits 92, 93, 100 and 102. Flow issuing from feedline 91 
into conduit 92 is vectored through pressure response valve 95. The 
response valve 95 as shown in the present embodiment is comprised of a 
housing 200 having a fixed orifice 202 formed therein. Adjacent fixed 
orifice 202 is a flexible orifice 204 which is responsive to the flow 
pressure of fluid passing therethrough. The fixed orifice 202 further 
defines an aperture 206 and flexible orifice 204 defines a variable 
aperture 208. Apertures 208 and 206 are aligned and the flow therethrough 
varies relative to the pressure exerted against flexible member 204. Flow 
210 engaging flexible member 204 is therefore adjusted whereby resultant 
flow 212 remains substantially constant. 
The utilization of fluid flow, pressure responsive valves is not, in and of 
itself, novel as discussed above. However, in the present invention the 
adjustable pressure responsive flow control valves are disposed in 
parallel flow communication with adjustable valves 96 and 103. Addressing 
valve 96, the adjustable valve of the present invention as depicted 
incorporates a needle valve comprising a handle 220 and stem 222 
actuatable by rotation within a needle valve housing 224. A needle valve 
stem 226 seated therein adjusts the flow of fluid 228 therethrough as is 
desirable for the particular flow application. It may be seen that valves 
96 and 101 are constructed substantially identically for permitting manual 
regulation of flow therethrough. In accordance with the principles of the 
present invention, this fluid flow regulation is preselected in accordance 
with the operation or characteristics of the vapor generator and the flow 
parameters of fuel and air which are likewise regulated for a dual flow 
configuration. Because water is the substance being vaporized, the precise 
regulation in a dual flow capacity is most critical. The feasibility of 
dual flow, adjustable, pressure responsive regulation over a multi-phase 
operation is a significant benefit and advantage over prior art systems. 
In the present embodiment, water flowing through the flow control network 
as set forth above is precisely controlled and adjustable although supply 
pressure may vary. Variations in supply pressure should be noted as being 
a significant contribution to vapor generation operation of the dual level 
or multi-phase level variety. The addition or deletion of substantial 
volumes of fluid flow will by definition increase and/or decrease any 
other fluid flow emanating from a single supply source. Such fluid flow 
perturbations are readily ascertainable in conventional plumbing systems 
both commercial and residential. However, in a commercial application of a 
vapor generator, such perturbations are critical to the performance 
characteristics and thus the value of the present invention should be 
readily recognizable. 
It may thus be seen from the aforesaid description of water flow system 90 
that for low volume output of the vapor generator system 10, by-pass valve 
97 remains closed to permit a single controlled flow volume through 
channel 91. For high output of the system 10, valve 97 is opened to permit 
parallel flow through the above-described by-pass system adjusted for 
matching the fuel-air flow volumes and combustion achieved thereby for 
high level output. Referring now to FIG. 3 there is shown an alternative 
embodiment of the vapor generator system 10 of the present invention 
wherein an automatic temperature control is provided as well as a modified 
flow circuit. As described herein, each of the solenoid valves above 
described in detail relative to FIGS. 1 and 2 are shown to be constructed 
as a solenoid valve operable by a central control unit. The automatic 
temperature control is achieved by the utilization of a third solenoid 
actuated water flow valve 300 disposed upstream of the two flow lines 93 
and 98 leading to the needle valves 96 and 103. In this manner, the 
central control unit can actuate flow through said needle valves as 
necessary to increase water flow and control output temperature. The 
needle valve flow line 98 is therefore shown shifted relative to the main 
flow line 100 depicted in FIG. 2. This particular flow and valve 
configuration allows the dual flow control of the needle valves 96 and 103 
by a single solenoid flow valve 300. The control unit 302 is coupled to 
the flow valve 300 by a control line 303. Likewise central control unit 
302 is coupled to solenoid flow control valve 80 by control line 380. 
Solenoid flow valves 78 and 86 are coupled to control unit 302 by control 
lines 378 and 386, respectively. Likewise, air dump silencer valve 112 is 
coupled to the central control unit 302 by control line 312. Flow valve 97 
is disposed downstream of the pressure responsive valve 101 and needle 
valve 103 as compared to the upstream positioning of FIGS. 1 and 2. In 
this position solenoid actuated flow valve 97 may be used more effectively 
due to the flow configuration of needle valve line 98. Solenoid flow 
control valve 97 is coupled to control unit 302 by control line 397. In 
this manner each of the flow control valves adapted for actuation for dual 
flow operation of the system 10 may be actuated simultaneously by a 
central control unit as well as the appropriate temperature control out of 
the vapor generator. A sensor 301 is thus provided in the discharge 
conduit 12 of the vapor generator 11 and coupled to the central control 
unit 302 by sensor line 310. In this manner control unit 302 may monitor 
the temperature of the discharge mixture of steam and non-condensible 
gases and automatically regulate the flow of water through the respective 
needle valves 96 and 103. 
In operation, pressure responsive valve 95 is sized to permit just less 
than sufficient flow for low fire operation. Needle valve 96 is set to 
permit flow in conjunction with pressure responsive valve 95 with slightly 
more water than is desired for low fire operation. In this manner solenoid 
actuated valve 300 allows water to flow through needle valve 96 only as 
needed to maintain a discharge temperature as measured by sensor 301 
within a preselect range. Solenoid valve 97 is open for high fire 
operation as is fuel flow valve 86. Dump silencer valve 112 is likewise 
shut for high volume operation. This permits fuel flow through both 
branches of the fuel flow circuit as well as water flow through both 
branches of the water flow circuit. Valve 96 is thus left with its 
previous setting with pressure responsive valve 101 sized such that with 
valves 95, 96 and 101 open there is not quite enough water to hold the 
desired steam exhaust temperature. Valve 103 is then adjusted to supply 
more water than is required by said valves to hold the desired steam 
exhaust temperature in the high fire configuration. A check valve 103A 
leads to valve 103 to permit flow in only one direction. The control unit 
302 cycles solenoid valve 300 based on the temperature readings at sensor 
301. The effect is a saw tooth temperature profile produced with a cycling 
temperature within a predesigned range. The solenoid flow control valve 
300 therefore kicks in during both high and low flow operation to permit 
control of the discharge temperature by utilizing preselect ranges in the 
needle valves 96 and 103. The utilization of pressure responsive valves 95 
and 101 in this configuration likewise permit uniformity and a preselected 
flow range and the advantages heretofore set forth in the application. 
Referring now to the oxidant, or air flow system designated generally as 
110, the main air flow conduit 25 is joined to by-pass conduit 24 at 
juncture 26. A remotely actuatable solenoid valve 112 is provided in line 
24 for selective actuation. Air flowing through valve 112 and through 
conduit 24 will be vented through dump silencer 114 and exhausted through 
conduit 116 in the manner deemed most preferable for the specific 
application. An orifice 118 is likewise provided for imparting select back 
pressure to the flow in conjunction with orifice 27 in the main flow line 
25 for select flow division with flow valve 112 in the open mode. In this 
manner, a select volume of air issuing from compressor or blower 21 will 
be diverted through the dump silencer 114 and vented rather than being 
permitted to pass into the combustion chamber 11. For low volume output of 
the generator system 10, the valve 112 is placed in the open position. In 
this manner, the motor 79 is permitted to operate at a uniform speed and 
with uniform heat dissipation irrespective of the output mode of the 
generator system 10. 
In operation, low output is thus achieved by actuating solenod valve 112 
into the open position with the compressor or blower 21 operational. The 
main water solenoid valve 80 is opened to permit flow with the pressure 
responsive valve 95 open and the adjustable, or needle valve 96 fine tuned 
to the specific low fire operation. Secondary water flow is prohibited by 
closure of secondary water solenoid 97. The pressure responsive valve 101 
in by-pass network 98 may remain open with adjustable valve, or needle, 
valve 103 remained fine tuned for high fire operation in that flow 
therethrough is not occurring. The fuel flow is likewise actuated through 
main line valve 78 in the open position, and by-pass solenoid 86 in the 
closed position. The adjustable or needle valves 84 and 87 both remained 
tuned to their respective flow positions. 
In the high volume output of the generator system 10, the solenoid valve 
112 is actuated to the closed position, water flow control by-pass valve 
97 actuated to the open position and fuel by-pass control valve 86 
actuated into the open position. All other settings remain the same as 
described above and no further adjustment is necessary. In this 
operational mode, the entire output from the compressor or blower 21 is 
channeled through the primary silencer 28 into the combustion chamber 11 
in conjunction with the dual water and fuel flows described above. It is 
believed that the operation and construction of the invention will be 
apparent from the foregoing description. While the apparatus thereof shown 
and described has been characterized as being preferred, it will be 
obvious that various changes and modifications may be made therein without 
departing from the spirit and scope of the invention as defined in the 
following claims.