US1951349A - Normalizer control - Google Patents

Description

March 2%,: 1934. W. DOBILE 3,951,349

NORMALI ZER CONTROL Filed Nov. 18 1950 A TTORNEYS. Q

Fatented Mar. 20, 1934 NORMALIZEE ooN'moL- Warren Doble, Emeryville, Calif. Application November 18, 1930, Serial No. 496,454

14 Claims.

My invention relates to means for controlling vapor generators and is especially concerned with boilers for producing super-heated steam. Such boilers are advantageously incorporated in power plants for use in automotive vehicles, such as automobiles, rail cars, airplanes and the like. Although the device of my invention is capable of use in various surroundings and can be utilized in connection with the production of vapors other than steam it is here described as it is embodied in a system for the production of steam for the propulsion of automobiles.

According to one system of furnishing steam for vehicle propulsion, it is preferred to utilize a boiler of the series tube type, more properly termed a forced circulation boiler. This boiler usually comprises a relatively small tube several hundred feet long which is subjected to a current of hot gases. Feed water isinjected into one end of the tube and, as it is forced through the tube, is gradually converted into wet steam and then into superheated steam which is discharged at the outlet end of the tube. Among other causes, but largely due to the variation in demand for steam under most operating conditions, the supplyoi heat for thetube and the supply of water pumped into the tube are both variable. In order to assure the production of steam of the desired characteristics such as pressure and temperature and particularly the latter, a thermostat is incorpo-' rated with the tube for controlling the heat supply. When the temperature rises to a predetermined value the thermostat interrupts the supply of heat. The tube and the contained steam then cool sufliciently so that the thermostat in response thereto again causes heat to be supplied. A comparable arrangement afiects the water supply except that customarily the pressure existing within the tube adjacent its outlet endis the controlling factor. Thus, when the pressure exceeds a predetermined value, the supply of water is interrupted while, when the pressure drops below the predetermined value, the supply of wateris initiated.

In order further to render the control of such a boiler a matter of delicacy and finesse, I have provided a device called a normalizer as disclosed in my copending application entitled Normalizer, Serial Number 21,262, filed September 22, 1927. According to the arrangement referred to, a portion of the feed water is branched from the source of feed water and is iniected'into the steam zone of the boiler tube a short distance in advance of the thermostat. The injection of this portion of the feed water is intermittently controlled by the thermostat iiself. In operation, as

the thermostat approximates the predetermined high temperature, it causes the supplemental portion of the feed water to be'injected into the hot steam. This water lowers the temperature of the steam and almost immediately cools the thermostat, thereby interrupting the supply of additional water.

In order for this system to be effective, I prefer that a deficiency of feed water be supplied at the inlet end of the boiler, the deficiency being with respect to the supply of heat or fire. Ordinarily the amount of feed water supplied at the inlet or foot of.the tube is about 90% of the total, leaving about 10% to be introduced directly into the steam zone through the additional or. normalizer opento ing. Also I preferably arrange so that the supply tof fire or heat to the tube is generally an excess with respect to the water supplied at the foot of the tube. Thus the temperature of the steam affecting the thermostat gradually tends to increase until the thermostat causes normalizerwater to be injected into the steam zone whereupon the temperature is relatively rapidly decreased until the supply of additional water is interrupted whereupon the temperature again tends slowly to rise.

By virtue of the fact that there is considerable pressure drop from the inlet end of the boiler tube to the outlet end, it is relatively easy for water to enter into the steam zone and, consequently, if there is any deficiency in the total feed water supplied, for instance because of inadequacy or failure of the supply pump or because of a deficiency at the source, the normalizer water is impaired little,if any, in quantity whereas the main supply to the foot of the boiler is considerably impaired. This leads to certain difiiculties which it is the general object of this invention to overcome. I

Another object of the invention is to prevent 05 localized overheating of the boiler.

Another object of the invention is to improve the operation of a forced circulation boiler.

The foregoing and other objects are attained in the embodiment of the invention shown in the drawing which is a schematic diagram disclosing the normalizer control of my invention as it is found in one environment. t In its preferred form, my normalizer control comprises a boiler into which supplemental feed water is injected for cooling the steam, the boiler being provided with means for interrupting the supply of supplemental feed water contingent rbipfin a predetermined thermal condition of the lid In the form of my invention which I have chosen to illustrate herein there is provided a boiler casing 6 within which are the convolutions of a boiler tube 7. Water for the boiler tube 7 is derived from a source of supply such as a tank 8, drawing from which is a pump 9 of any suitable kind. In the present instance, the pump 9 is operated by steam conducted to the pump through a conduit 11 joined to the steam outlet 12 of the boiler tube 7 in advance of the main throttle valve 13. Water discharged under pressure by the water pump 9 flows through a duct 14 past a constriction suitably provided by an adjustable valve 16 and into the inlet end 17 of .the tube 7. Shunting the constriction 16 is a piston 18 one face of which is subjected to pressure existing within duct 14 while the other face of the piston 18 is subjected to the pressure existing within the inlet portion 17 of the boiler tube 7 and to the pressure of a biasing spring 19. The piston 18 reciprocates in response to fluctuations in the pressure drop across the constriction 16 and the motion of the piston is transmitted through a rocker 21 to a throttle valve 22 controlling the amount of steam flowing to the water pump 9.

When an excessive amount of water is dis- ,charged by thepump 9, the pressure within the duct 14 rises and displaces the piston 18 to oscillate the rocker 21 so that the supplyof steam flowing through the valve 22 to the pump 9 is suitably decreased thereby reducing the amount of water flowing. On the other hand, if the pump 9 is discharging an insufiicient amount of water, the pressure on the boiler inlet side of the constriction 16 is suflicient to lower the piston 18 and increase the speed and output of the pump 9 by permitting more steam to pass through valve 22.

The water which flows into the boiler tube 7 is advanced therethrough by the pump and is-heated'as it advances. Heat is furnished to the interior of the boiler casing 6 by a blower 23 driven by an electric motor 24 and causing a current of air to flow through a duct 26. A carbureting device 27 communicating with the duct introduces fuel into the air stream. A spark plug 28 ignites the mixture as it enters the firebox 29 of the boiler. The combustion ensuing in the firebox produces hot products of combustion which travel over the convolutions of the tube 7 and are expelled from the outlet 31.

In order to control the period of operation of the blower 23 a thermostat 32 is provided between adjacent convolutions of the tube 7. In the present instance, the thermostat includes a rod 33 of substantially non-expanding material within a shell 34 of expanding material so that upon an increase in temperature, the rod 33 moves toward the left in the figure. A rocker 36 is mounted on a pivot 37 and is urged by a spring 38 into contact with the thermostat rod 33. Pivoted adjacent one arm 39 of the rocker 36 is a lever 41 pressed by a spring 42 against the arm and carrying a contact 43. Co-operable with contact 43 is a counter-contact 44 in an electric circuit which includes a wire 46 leading to one terminal 47 of a master switch 48. A source of electricity,

such as a storage battery 49 is connected by. a wire 51 to the master switch. 48 and by a lead 52 to ground.

When the temperature is low and the master switch 48 is closed, the circuit is completed through contact 44, which, since it is then in abutment withcontact 43, permits current to flow through a wire 53-;to the electric motor 24 76 from whence the return is through a wire 54 to ground. The blower 23, being thus energized, operates to furnish the boiler with heat. As soon as the temperature of the thermostat 32 arrives at a predetermined value, expansion of the thermostat permits the rod 33 to retract and the spring 38 overcomes the bias of spring 42 and separates the contacts 43 and 44. The electric circuit to the blower motor 24 is thus interrupted and the supply of heat to the boiler ceases. As soon as the temperature falls below the predetermined value, however, the rod 33 again projects and oscillates the rocker 36 about pivot 37 so that the arm. 39 moves against the bias of spring 38. This permits spring 42 again to close contacts 43 and 44, re-establishing the circuit to the electric motor 24 so that the blower again operates and the supply of heat is renewed.

In addition to the foregoing mechanism for controlling the temperature of the steam produced by the boiler, I provide means for introducing additional feed water into the boiler tube 7 adjacent the thermostat 32. The rocker 36 is provided with an arm 56 in the path of which is a lever 57 biased by a spring 58. As the thermostat rod 33 retracts, the lever 57 moves so that a contact 59 on the lever abuts a contact 61 to complete an electrical circuit from the terminal 47 through a lead 62 and a lead 63, through contacts 64 and 66 and through a wire 67 to a solenoid 68 'from whence the circuit is grounded by a wire 69.

The solenoid 68 controls the operation of a valve 71 which is interposed in a fluid line ineluding a pipe 72 extending from the water outlet of the pump 9 through the valve 71 into a duct 73 leading to the tube 7 of the boiler at a point somewhat in advance of the thermostat 32. The region of injection of additional water, as controlled by the valve 71, is designated B while the portion of the boiler tube which is directly effective upon the thermostat 32 is designated C. In operation, the contacts 59 and 61 are adjusted so that. they make contact a few degrees before contacts 43 and 44 are broken by expansion of the thermostat 32 in response to temperature in the region C of the tube 7. Consequently, slightly before the electric current supply to the blower 23 is interrupted, the solenoid 68 is energized and water is permitted to pass from the pump 9 through the pipes 72 and 73 into the region B of the boiler just in advance of the thermostat 32. Usually during the operation of the boiler, although somewhat dependent upon the amount of steam being discharged from 'the' boiler, the additional water introduced at the region B is suificient to cool the thermostat 32 quickly and prevent further expansion thereof so that the contacts 43 and 44 are not separated. Further, the thermostat usually is cooled sufiiciently to break the circuit controlled by contacts 59 and 61 thereby de-energizing the solenoid 68 and stopping the supply of additional water through the pipe 73. This cycle often repeats itself an indefinite number of times, furnishing an intermittent supply of additional feed water into the portion B of the boiler" tube 7.

It sometimes happens, however, due to a deficiency of water supp y or from other causes,

that the primary portion of the boiler tube 7, which is supplied with water through the inlet 17, receives a marked deficiency of water although the supply through the duct 73 is substantially the requisite amount. The supplemental water flowing through the tube 73 is sufficient to cool the thermostat 32 so that ordinarily the contacts 43 and 44 do not break and heat is added continuously to the boiler,- whereas there is a deficiency of water entering the inlet 17 and the portion A of the boiler may become excessively hot and may rupture.

For this reason I provide an additional thermostat 74 at the region A'of the boiler. This thermostat preferably includes'a rod 76 of substantially non-expanding material which abuts the closed inner end of the tube 74 and retreats within the tube 74 as the temperature increases since the open end of the tube 74 is fixed on the boiler casing 6. Pressed into contact with the rod 76 isa lever 77 pivoted, as at 78, and biased by a contractile spring 79. Oneend of the lever 77 carries the contact 64 which co-operates with the contact 66, as previously described. Normally, and when the temperature of the tube 7 in the region A of the boiler is below a predetermined value the rod 76 maintains the lever 77 in such a position that the contacts 64 and 66 are in abutment and permit the circuit to be closed. However, upon the attainment of an excessive temperature or a temperature in excess of a predetermined value in the region A of the boiler, the rod76 retracts due to the expansion of the tube 74 and consequent movement of its closed end away from its fixed, open end and permits the spring 79 to withdraw the lever 77 so that the contact 64 is lifted from the contact 66 and the circuit to the solenoid 68 is interrupted. 1

The result of interrupting the operation of the valve 71 by virtue of de-energizing the solenoid 68 is that no additional water can be supplied through the duct 73 to the region B of the boiler tube 7 and the cooling effect of additional water which might otherwise be introduced is therefore precluded. Heat travels, therefore, not only directly into the region C of the boiler tube from the hot gases of combustion but also "travels rather rapidly along the tube 7 and promptly increases the temperature of the thermostat. If the increaseis sufiicient, the-contacts 43 and 44 are opened thereby stopping the blower 23 and interrupting the supply of heat. This action is adjusted to take place before any portion of boiler tube 7 has attained an excessive temperature, particularly the, portion A which often is the hottest, and therefore any danger of rupture or other damage is obviated.

It is to be understood that I do not limit myself to the form ofthe normalizer control shown and described herein, as the invention. as set forth in the claims may be embodied in a plurality of forms.

I claim:

1. A normalizer control comprising a boiler tube, means for heating said tube, means responsive to temperature for controlling said heating means, means for affecting said temperature responsive means, anda second temperature responsive means unafiected by said affecting means for controlling said affecting means? 2 A normalizer control comprising a tube, means for heating, said tube, means for introducing a fluid into said tube, means responsive to temperature of fluid in said tube for controlling said heating means, means for introducing additional fluid into said tube in response to.

said temperatureresponsive means, and a sec-. temperature-responsive means for disabling said additional fluid introducing means.

3. A normalizer control comprising a tube, a temperature responsive means in said tube, means for introducing fluid into said tube remotely to affect said temperature responsive means, means for introducing fluid into said tube immediately to affect said temperature responsive means, and a second temperature responsive means unaffected by said last named introducing means for controlling said last-named introducing means.

4. A normalizer control comprising a boiler tube, means for heating said tube, means for introducing water into said tube for conversion therein into steam, a thermostat responsive to steam temperature in said tube for controlling said heating means, means for introducing additional water into said tube for cooling said thermostat, and means responsive to temperature within said tube and unaffected by said additional water for controlling the operation of said means for introducing additional water.

5. A normalizer control comprising a tube adapted to be heated, a pair of thermostats responsive to temperatures in said tube, means for cooling one of said thermostats, and means controlled by the other of said thermostats for controlling the operation of said cooling means. 6. A normalizer control comprising a tube adapted to be heated, a pair of thermostats responsive to temperatures in said tube, means responsive to one of said-thermostats for introducing fluid into said tube for cooling said thermostat, and meansresponsive to the other of said thermostats for preventing theoperation of said introducing means.

7. A normalizer control comprising a tube, a thermostat in said tube, means for affecting the temperature of said thermostat, and a second '-thermostat unaffected by said affecting means for controlling the operation ofsaid aifecting means.

8. A normalizer control comprising mechanism for use with a forced circulation steam boiler in which feed water is periodically injected into the steam in response to excess temperature, the mechanism including a thermally responsive means for interrupting the injection of feed water into the steam despite said excess temperature. I

9. A normalizer control comprising a tube through which. fluid is adapted to flow in but one general direction, means for heating said tube, means for introducing water into said tube at a point between the ends of said tube, and means responsive. to the temperature of said tube in advance of said point for preventing the operation of said introducingmeans.

10. A normalizer control comprising mechanism. for use witha forced circulation steam boiler in which feed water is periodically injected into the steam in response to excess -tem-= perature, the mechanism including means for interrupting the injection of feed water into the steam despite said excess temperature.

11. A nornializer control comprising mechanism'for use with a forced circulation steam boiler in which feed water is periodically injected into the steam in response to excess temperature, the mechanism including means automatically effective during the operation of the boiler for M5 interrupting the injection of feed water into the steam despite said excess temperature.

12. A normalizer control comprising mecha- M ll) nism for use with a forced circulation steam in response to excess temperature, the mechanism including means eiiective during the operation of the boiler for interrupting the injection of water into the steam despite said excess temperature.

13. A normalizer control comprising a tube through which fluid is adapted to flow in but one general direction, means for varying the temperature of said tube, means for introducing fluid into said tube at a plurality of points spaced in said general direction, and means responsive to excessive temperature of said tube for preventing the introduction of said fluid at the final one of said points.

14. A normalizer control comprising a tube through which fluid is adapted to flow in but one general direction, means responsive to the WARREN nonra-

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