Method and apparatus for managing steam systems

• US 4,705,212 A
• Filed: 12/27/1983
• Issued: 11/10/1987
• Est. Priority Date: 12/27/1983
• Status: Expired due to Fees

• Current Assignee: Engineering Measurements Co. (Advanced Energy Industries Incorporated)
• Original Assignee: Engineering Measurements Co. (Advanced Energy Industries Incorporated)
• Inventors: Miller, Charles E., Yoshida, Louis T., Poland, Robert L.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/565,362
• Time in Patent Office: 1,414 Days
• Field of Search: 236/84, 236/53, 236/54, 236/55, 236/68 D, 236/80 R, 237/68, 236/80 F, 251/30, 137/171, 137/197
• US Class Current: 236/54
• CPC Class Codes: F16T 1/00 Steam traps or like apparatus for draining-off liquids from enclosures predominantly containing gases or vapours, e.g. gas lines, steam lines, containers
• CPC Class Codes: F16T 1/45 Means for venting or aerating separate devices therefor F16K24/00
• CPC Class Codes: Y10T 137/3003 Fluid separating traps or vents

Abstract

A steam system management method and apparatus includes a condensate collection reservoir with a pilot operated, pressure actuated dump valve that has a quick, snap action fully open/fully closed mode of operation. The pilot operation of the dump valve is actuated by a very low voltage solenoid actuator powered by a thermal-electric generator which thermionically converts heat from the steam system directly to electricity. Condensate dumps are controlled by liquid level sensing switches positioned near the top and bottom of the reservoir and electrically connected to a relay logic that turns the solenoid on and off. Temperature sensors positioned in the steam system and adjacent the thermal-electric generator are utilized in combination with the thermal electric generator and a microprocessor to monitor the air content in the steam system and to open the dump valve to purge excess air from the steam system. A voltage converter and voltage regulator are provided to convert very low voltage output from the thermal-electric generator to a higher voltage necessary to operate the microprocessor, and management information output displays are provided to indicate valve status, modes of operation, quantities of condensate dumped, and failure alarm.

Claims

1. Steam system management apparatus, comprising:

a reservoir having an inlet adapted for connection to a steam distribution system and an outlet;

electronically actuated valve means for opening and closing said outlet;

thermal electric generator means for converting heat energy in the steam system into electrical energy for operating said electronically actuated valve means; and

temperature control means for limiting the temperature of the heat applied to said thermal electric generator means.

2. The steam system management apparatus of claim 1, wherein said pilot actuated valve means includes pressure actuated main valve means positioned in said outlet for selectively opening and closing said outlet, pressure distribution means for directing a fluid under pressure to said main valve means, and pilot valve means in said pressure distribution means for selectively applying and releasing pressure on said main valve means.

3. The steam system management apparatus of claim 2, wherein said main valve means includes an outlet nozzle in said outlet with a valve seat thereon, a moveable stopper element adapted to close said outlet nozzle by seating on said valve seat and opening said outlet nozzle by moving off said valve seat, piston means connected to said stopper for moving said stopper onto said valve seat in response to a pressure applied on said piston means.

4. The steam system management apparatus of claim 3, wherein said pressure distribution means includes a pressure fluid conduit connected to said outlet upstream from said outlet nozzle and opened onto said piston means, and wherein said piston means has an area larger than the cross-sectional area of said outlet nozzle at said valve seat.

5. The steam system management apparatus of claim 4, including filter means positioned in said outlet over the connection of said pressure fluid conduit for preventing solid matter from entering said pressure fluid conduit.

6. The steam system management apparatus of claim 5, wherein said filter means is positioned in said outlet in a manner to not inhibit and filter fluid flowing to said outlet nozzle.

7. The steam system management apparatus of claim 4, wherein said pressure distribution means includes pressure bleed means for bleeding pressure off said piston means.

8. The steam system management apparatus of claim 7, wherein said pressure bleed means includes bleed conduit connected to said pressure fluid conduit between said pilot valve means and said piston means and connected to said outlet downstream from said outlet nozzle.

9. The steam system management apparatus of claim 8, including bleed valve means in said bleed conduit for closing said bleed conduit when said pilot valve means is opened to apply pressure on said piston means and for opening said bleed conduit when said pilot valve means is closed to relieve pressure on said piston means.

10. The steam system management apparatus of claim 9, wherein said pressure distribution means and said pressure bleed means have a common valve chamber, and said pilot control means includes a common armature in said valve chamber with said pilot valve means positioned on and connected to one side of said armature and said bleed valve means positioned on and connected to the opposite side of said armature in such a manner that movement of said armature in one direction causes said bleed valve means to close while said pilot valve means opens simultaneously and movement of said armature in the opposite direction causes said pilot valve means to close while said bleed valve means opens simultaneously.

11. The steam system management apparatus of claim 10, wherein said pilot control means also includes an electric solenoid adjacent said armature for moving said armature in one direction upon application of an electric current to said solenoid and spring bias means connected to said armature for moving said armature in the opposite direction upon termination of the electric current in said solenoid.

12. The steam system management apparatus of claim 2, including a moveable armature connected to said pilot valve means, an electric solenoid adjacent said armature for moving said armature in one direction, and spring bias means connected to said armature for moving said armature in the opposite direction.

13. The steam system management apparatus of claim 2, wherein said air detection means includes thermal electric generator means for converting heat energy in the steam system into electric energy for operating said solenoid, and heat sensor means adjacent the side of said thermal-electric generator that is opposite said inlet and which is adapted to output an electric signal in relation to the temperature at the position of the heat sensor means, and computer means for constantly calculating a thermal transfer efficiency value by dividing the electrical output of the thermal-electric generator by electrical output of the heat sensor means and for calculating the actual rate of thermal transfer efficiency change during the air purge and comparing the actual rate of thermal transfer efficiency change to a predetermined standard rate of thermal transfer efficiency change corresponding with the predetermined minimum amount of air and outputting a signal to said solenoid actuator means to energize said solenoid to terminate the air purge when the actual rate of thermal transfer efficiency change equals and is less than the predetermined standard rate of thermal transfer efficiency change, and for constantly monitoring the actual thermal transfer efficiency of the steam system when air is not being purged and comparing the actual thermal transfer efficiency with a predetermined maximum acceptable percentage variation from the thermal transfer efficiency at the termination of the preceding air purge corresponding with the predetermined maximum acceptable amount of air in the steam system and outputting a signal to said solenoid actuator means to deenergize said solenoid to start an air purge when the actual thermal transfer efficiency of the steam system varies at least as much as the predetermined maximum acceptable percentage variation from the thermal transfer efficiency at the termination of the preceding air purge.

14. The steam system management apparatus of claim 13, wherein said temperature measuring means is a thermistor which produces a continuous analog electrical output corresponding to the temperature of the fluids in the steam system, and said computer means includes an analog to digital converter for converting the analog output of the termistor to digital data per predetermined time intervals and a digital computer processing unit operating system for performing the required algorithms, and the output of said computer means to said solenoid actuator means is digital.

15. The steam system management apparatus of claim 13, wherein said solenoid actuator means includes second relay means for opening the electrical circuit to deenergize said solenoid in response to said signal from said computer means to start an air purge and for closing the electrical circuit to energize said solenoid in response to said signal from said computer means to terminate an air purge.

16. The steam system management apparatus of claim 13, including low level alarm means for alerting attending personnel of excessively long periods of the main valve means being open.

17. The steam system management apparatus of claim 16, wherein said low level alarm means includes an output signal capable of being detected by a person'"'"'s natural senses, an input signal to said computer means from said solenoid actuation means when said solenoid is deenergized, wherein said computer means is adapted to compare the time the solenoid is deenergized with a predetermined standard time corresponding to the normal time interval between deenergization of the solenoid when said reservoir is full of liquid and energization of the solenoid when said reservoir is empty of liquid and outputting a signal to said low level alarm means when the solenoid is deenergized for a time period longer than said predetermined standard time.

18. The steam system management apparatus of claim 4, wherein said piston means includes a pressure chamber, a rigid body positioned slidably in said pressure chamber, and a flexible membrane attached to said rigid body and extending radially outward therefrom into sealed contact around its entire peripheral surface with the interior walls of said pressure chamber.

19. The steam system management apparatus of claim 17, wherein said low level alarm means includes an electromagnetic signal transmitter, a receiver at a remote location, and an alarm signal generator at the remote location connected to the receiver.

20. The steam system management apparatus of claim 17, wherein said low level alarm means includes a visual display.

21. The steam system management apparatus of claim 1, including heat sink means in contact with said thermal electric generator means for drawing heat away from said thermal electric generator means.

22. The steam system management apparatus of claim 21, wherein said heat sink means includes heat dissipating means for dissipating and disposing of the heat energy drawn away from the thermal electric generator means.

23. The steam system management apparatus of claim 22, wherein said heat dissipating means includes a plurality of fins for dissipating heat energy into the atmosphere.

24. The steam system management apparatus of claim 1, wherein said thermal electric generator means includes means for converting heat energy directly to electrical energy.

25. The steam system management apparatus of claim 24, wherein said thermal electric generator means is a semiconductor device which generates an electric current and voltage when there is a temperature differential from one side to the other.

26. The steam system management apparatus of claim 1, wherein said thermal electric generator means is positioned adjacent said inlet.

27. The steam system management apparatus of claim 1, wherein said temperature control means includes a moveable heat conductor means positioned between the heat source and said thermal electric generator means, and heat sensitive moving means connected to said heat conductor means for moving said heat conductor means towards said thermal electric generator as the temperature decreases and for moving said heat conductor means away from said thermal electric generator means as the temperature increases.

28. The steam system management apparatus of claim 27, wherein said heat sensitive moving means includes a bimetalic spring connected to said heat conductor means for moving said heat conductor means away from said thermal electric generator means as the temperature increases and for moving said heat conductor means toward said thermal electric generator means as the temperature decreases.

29. The steam system management apparatus of claim 28, wherein said heat sensitive moving means includes bias means connected to said heat conductor means for biasing said heat conductor means toward said thermal electric generator means, the bias of said bias means being sufficiently strong to prevent said bimetalic spring from moving said heat conductor means away from said thermal electric generator means until the temperature rises to a predetermined magnitude.

30. The steam system management apparatus, comprising:

a reservoir with an inlet and an outlet;

valve means in said outlet for opening and closing said outlet, said valve means including an electric solenoid actuator;

thermal electric generator means adjacent said inlet for producing electric power of about one volt of direct current potential thermionically from heat in the steam system for energizing said solenoid actuator; and

electronic control means for controlling the electric power to actuate and deactuate said solenoid, said electronic control means including a voltage converter for converting the one volt electric power to about five volts of electric power, said voltage converter including an inductor coil, one end of which is connected to said one volt electric power and the other end of which is connected to ground, switch means between said other end of said inductor coil and the connection to ground, and a high voltage power output line with a rectifier diode therein connected to said other end of said coil between said other end of said coi and said switch means being timed to switch on a longer time to charge the inductor with the one volt power than it is switched off to discharge the coil through the high voltage output line.

31. The steam system management apparatus of claim 30, wherein said switch means includes a first transistor connecting said other end of said inductor to ground and an oscillator circuit connected to said one end of said inductor coil for turning said first transistor on and off, said oscillator circuit including a capacitor and a first resistor in parallel to each other connected between a second resistor and a diode in parallel to each other, said capacitor and the emitter of said diode being connected to the base of said first transistor, and a second transistor positioned to shunt said second resistor and said capacitor to ground, the base of said second transistor being connected to said high voltage output line.

32. The steam system management apparatus of claim 31, including a voltage regulator circuit connected to the base of said second transistor for overriding said oscillator circuit to turn off said first transistor when the voltage on said high voltage output line exceeds five volts.

33. The steam system management apparatus of claim 32, wherein said regulator circuit includes a third transistor connected between said high voltage output line and the base of said second transistor for turning said second transistor on and off, and a balancing circuit for controlling said third transistor having a Zener diode regulator and a resistor connected in series on a first shunt line between the high voltage output line behind said rectifier diode and ground for maintaining a precision, nonvarying voltage on said first shunt line, a voltage splitter line between said high voltage output line behind said rectifier and ground having two resistors connected in series therein, with the value of these two resistors being sized to split the voltage in such a manner that when there is the desired five volts on the hgh voltage output line, the voltage between these two resistors is equal to the precision voltage on said first shunt line, a transistor control line extending from the base of said third transistor to ground and having a fourth transistor therein with its base connected to said voltage splitter line between said two resistors therein and a bias line with a resistor therein connected between said high voltage output line behind said rectifier and said transistor control line between said third and fourth transistors, and a second shunt line extending from said high voltage output line behind said rectifier to ground and having a fifth transistor therein with its base connected to said first shunt line where said precision voltage is maintained.

34. In a steam system having a valve therein for opening said system to the outside, a method for controlling the air content in the steam system, comprising the steps of:

positioning a thermal-electric generator capable of generating electric power thermionically from heat transfer therethrough adjacent a heat conducting wall of said steam system;

connecting an electric solenoid to said valve for opening and closing said valve;

operating said solenoid with the electric power generated by said thermal-electric generator to open said valve to purge air from the steam system and closing said valve to terminate the purge;

determining the thermal transfer efficiency E* by providing said thermal-electric generator in a form that produces an electric potential in proportion to the quantity of heat conducted therethrough;

positioning a first temperature sensing device capable of outputting a voltage in relation to temperature in the steam system adjacent said heat conducting wall;

positioning a second temperature sensing device capable of outputting a voltage in relation to temperature at the side of said thermal-electric generator opposite said heat conducting wall;

dividing the magnitude of voltage produced by said thermal-electric generator by the difference between the respective magnitudes of the voltage outputs of said first and second temperature sensors, comparing said thermal transfer efficiency E* with a predetermined reference thermal transfer efficiency E*; and

actuating said solenoid to open said valve to purge air from the steam sytem when the actual thermal transfer efficiency varies a predetermined amount from the reference thermal transfer efficiency E*.

35. The method of claim 34, including the step of establishing said thermal transfer efficiency reference e*_REF corresponding to an acceptable amount of air in the steam system by opening said valve to purge air from the system, and, during the purge, using a microprocessor to continuously monitor the voltage outputs of the thermal-electric generator and the two temperature sensors and to continuously calculate the thermal transfer efficiency E* of the steam system during the purge, and to also calculate the rate of change of the thermal transfer efficiency E*, continuously comparing the rate of change of the thermal transfer efficiency E* with a predetermined maximum rate of change corresponding with an acceptable amount of air in the steam system, and, when the actual rate of change decreases to the predetermined maximum acceptable rate of change, outputting a signal to actuate said solenoid to close the valve and terminate the purge, and set the actual thermal transfer efficiency E* as the reference thermal transfer efficiency E*_REF.

36. The method of claim 35, including the steps of connecting a reservoir to said steam system for collecting and retaining condensate, positioning said valve at the bottom of said reservoir, positioning an upper liquid level sensor switch near the top of said reservoir and a lower liquid level sensor switch near the bottom of the reservoir, and connecting said level sensor switches to said electrical power from said thermal electric generator and said solenoid to actuate said solenoid to open said valve when the condensate level in the reservoir reaches the upper sensor switch and to close said valve when the condensate level falls to said lower sensor switch and the thermal transfer efficiency E* is still within the acceptable band of variation from E*_REF.

37. The method of claim 36, including the steps of utilizing the microprocessor to also continuously monitor the time required for the reservoir to fill with condensate from the low level sensor to the upper level sensor and to dump the condensate by connecting the electric circuit that powers the solenoid also to said microprocessor to input a signal to the microprocessor when the solenoid is turned on and off to actuate said valve closed and open, to use the volume of the reservoir and time of fill to calculate the rate of condensate flow into the reservoir, and utilizing the rate to calculate the volume of the next succeeding dump by multiplying the rate of inflow times the time of the dump and adding the product to the volume of the reservoir, and to output a signal to actuate a totalizer to register the volume of the dumps.

38. The method of claim 37, including the steps of monitoring the times the solenoid is actually actuated to open the valve and to close the valve during condensate dumps and air purges and comparing those times with predetermined acceptable reference times for these modes, and outputting a signal to actuate an alarm whenever any of these actual times exceed the predetermined reference times.

39. A method of controlling the amount of entrained air in a steam system, comprising the steps of:

positioning a thermal-electric generator, which is adapted to produce electricity thermionically from heat in relation to the quantity of heat flowing therethrough, adjacent a heat conducting wall of a steam system;

positioning a first temperature sensor, which is adapted to output an electric signal in relation to temperature, adjacent said thermal-electric generator on a side thereof opposite the heat conducting wall of the steam system;

dividing the electric output of the thermal-electric generator by the output of the first temperature sensor and comparing the dividend with a predetermined reference value corresponding to an acceptable amount of air in the steam system; and

opening a valve in the steam system to the outside of the steam system to purge excess air from the steam system when said dividend varies a predetermined amount from said reference value corresponding to an unacceptable amount of air in the steam system.

40. The method of claim 39, including the steps of:

determining said reference value by opening said valve to purge air from the steam system;

continuously sampling the electrical outputs of the thermal-electric generator and the first temperature sensor and dividing the electrical output of the thermal electric generator by the electrical output of the first temperature sensor, and continuously comparing each dividend with the preceding dividend at unit time intervals to determine the rate of change of each successive dividend;

continuously comparing the rate of change of the successive dividends with a predetermined reference rate of change corresponding to an acceptable amount of air in the steam system; and

closing the valve when the actual rate of change of the dividends decreases to the reference rate of change to terminate the purge.

41. The method of claim 40, including the step of closing said valve only after the rate of change of the dividends does not exceed the reference rate of change for a predetermined period of time corresponding to stabilized conditions of air content, temperature, and pressure of the steam system.

42. A method of controlling the amount of entrained air in a steam system, comprising the steps of:

positioning a thermal-electric generator, which is adapted to produce electricity thermionically from heat, adjacent a heat-conducting wall of a steam system;

positioning a first heat sensor, which is adapted to output an electric signal in relation to temperature, adjacent said thermal-electric generator on a side thereof opposite the heat-conducting wall of the steam system;

positioning a first heat sensor, which is adapted to output an electric signal in relation to temperature, adjacent said thermal-electric generator on a side thereof opposite the heat-conducting wall of the steam system;

positioning a second heat sensor, which is adapted to output an electric signal in relation to temperature, adjacent said heat conducting wall of said steam system;

dividing the electric output of the thermal-electric generator by the difference between the electric outputs of the first and second heat sensors and comparing the dividend with a predetermined reference value corresponding to an unacceptable amount of air in the steam system; and

opening a valve in the steam system to the outside of the steam system to purge excess air from the steam system when said dividend varies a predetermined amount from said reference value corresponding to an unacceptable amount of air in the steam system.

43. Steam system management apparatus, comprising:

a reservoir having an inlet adapted for connection to a steam distribution and an outlet;

pilot actuated valve means for opening and closing said outlet, said pilot actuated valve means including pressure actuated main valve means positioned in said outlet for selectively opening and closing said outlet, pressure distribution means for directing a fluid under pressure to said main valve means, and pilot valve means in said pressure distribution means for selectively applying and releasing pressure on said main valve means;

pilot control means for actuating said pilot valve means, including a moveable armature connected to said pilot valve means, an electric solenoid adjacent said armature for moving said armature in one direction, spring bias means connected to said armature for moving said armature in the opposite direction, and solenoid actuator means electrically connected to said thermal electric generator means and said solenoid for selectively energizing and deenergizing said solenoid, and

liquid level sensing means in said reservoir for sensing when said reservoir is full of liquid and when it is empty of liquid, said liquid level sensing means being connected to said solenoid actuator means to energize said solenoid to close said main valve means when said reservoir is empty of liquid and to deenergize said solenoid to open said main valve means when said reservoir is full of liquid.

44. The steam system management apparatus of claim 43, wherein said solenoid actuator means includes first relay means for closing an electric circuit to energize said solenoid when said reservoir is empty of liquid and for opening the electric circuit to deenergize said solenoid when said reservoir is full of liquid.

45. The steam system management apparatus of claim 44 wherein said pilot control means includes air detection means for detecting the amount of air in the steam system, said air detection means being connected to said solenoid actuator means to deenergize said solenoid to open said main valve means for purging the air from the steam system when a predetermined maximum acceptable amount of air is detected in the steam system and to energize said solenoid to close said main valve means to terminate the air purge when a predetermined minimum amount of air is detected in the steam system.

46. The steam system management apparatus of claim 44, wherein said liquid level sensing means includes a lower level switch positioned at the bottom of the reservoir for actuating said first relay means to close the electric circuit to said solenoid and an upper level switch positioned at the top of the reservoir for actuating said first relay means to open the electric circuit to said solenoid.

47. The steam system management apparatus of claim 46, wherein said lower and upper level switches are magnetically operated reed switches and said liquid level sensing means also includes a float in said reservoir with a magnet positioned therein, said float and magnet being adapted to move into a position adjacent said lowr reed switch when said reservoir is empty of liquid and to move into a position adjacent said upper reed switch when said reservoir is full of liquid.

48. The steam system management apparatus of claim 47, wherein said liquid level sensing means includes an elongated vertical tube extending from the top to the bottom of said reservoir, said upper and lower reed switches being positioned inside said tube and said float and magnet being slidably positioned around the exterior surface of said tube.

49. Steam system management apparatus for steam systems having steam-containing components and heat transfer surfaces through which heat transfers from steam in the system, comprising:

a reservoir having an inlet for connecting said reservoir to a steam distribution system and an outlet;

valve means for opening and closing said outlet; and

air detection means for detecting the amount of air in the steam system, said air detection means being connected to said valve means to open said valve means for purging the air from the steam system when a predetermined maximum acceptable amount of air is detected in the steam system and to energize said solenoid to close said valve means to terminate the air purge when a predetermined minimum amount of air is detected in the steam system, said air detection means including heat transfer detection means positioned at a heat transfer surface for detecting heat transfer through the heat transfer surface.

50. The steam system management apparatus of claim 49, wherein said air detection means includes a thermal electric generator positioned with one side adjacent said inlet, heat sensor means adjacent the side of said thermal-electric generator that is opposite said inlet and which is adapted to output an electric signal in relation to the temperature at the position of the heat sensor means, the computer means for constantly calculating a thermal transfer efficiency value by dividing the electrical output of the thermal-electric generator by electrical output of the heat sensor means and for calculating the actual rate of thermal transfer efficiency change during the air purge and comparing the actual rate of thermal transfer efficiency change to a predetermined standard rate of thermal transfer efficiency change, and for constantly monitoring the actual thermal transfer efficiency of the steam system when air is not being purged and comparing the actual thermal transfer efficiency with a predetermined maximum acceptable percentage variation from the thermal transfer efficiency at the termination of the preceding air purge corresponding with the predetermined maximum acceptable amount of air in the steam system and outputting a signal to said valve means to open said outlet to start an air purge when the actual thermal transfer efficiency of the steam system varies at least as much as the predetermined maximum acceptable percentage variation from the thermal transfer efficiency at the termination of the preceding air purge.

51. The steam system management apparatus of claim 50, wherein said temperature measuring means is a thermistor which produces a continuous analog electrical output corresponding to the temperature of the fluids in the steam system, and said computer means includes an analog to digital converter for converting the analog output of the thermistor to digital data per predetermined time intervals and a digital computer processing unit operating system for performing the required algorithms, and the output of said computer means to said valve means is digital.

52. The steam system management apparatus of claim 50, including low level alarm means for alerting attending personnel of excessively long periods of the valve means being open.

53. The steam system management apparatus of claim 52, wherein said low level alarm means includes an output signal capable of being detected by a person'"'"'s natural senses, an input signal to said computer means from said valve means when said outlet is opened, wherein said computer means is adapted to compare the time the outlet is opened with a predetermined standard time corresponding to the normal time interval between opening said outlet when said reservoir is full of liquid and closing said outlet when said reservoir is empty of liquid and outputting a signal to said low level alarm means when the outlet is opened for a time period longer than said predetermined standard time.

54. The steam system management apparatus of claim 53, wherein said alarm means includes a visual display.

55. The steam system management apparatus of claim 53, wherein said alarm means includes an electromagnetic signal transmitter, a receiver at a remote location, and an alarm signal generator at the remote location connected to the receiver.

56. Steam management system apparatus, comprising:

a reservoir having an inlet for connecting said reservoir to a steam system and an outlet;

valve means for opening and closing said outlet;

computer means for constantly monitoring the times the valve means remains open; and

alarm means for alerting attending personnel of excessively long periods of the valve means remaining open, said alarm means including an output signal capable of being detected by a person'"'"'s natural senses, an input signal to said computer means from said valve means when said outlet is opened, wherein said computer means is adapted to compare the time the outlet is opened with a predetermined standard time corresponding to the normal time interval between opening of said outlet when said reservoir is full of liquid and closing said outlet when said reservoir is empty of liquid and outputting a signal to said low level alarm means when the outlet is opened for a time period longer than said predetermined standard time.

57. In a steam system having a valve therein for opening said system to the outside, a method for controlling the air content in the steam system, comprising the steps of:

positioning a thermal-electric generator capable of generating electric power thermionically from heat transfer therethrough adjacent a heat conducting wall of said steam system;

connecting a reservoir to said steam system for collecting and retaining condensate;

positioning a solenoid valve at the bottom of said reservoir;

positioning an upper liquid level sensor switch near the top of said reservoir and a lower liquid level sensor switch near the bottom of the reservoir; and

connecting said level sensor switches to said electrical power from said thermal electric generator and said solenoid valve to actuate said solenoid valve to open said solenoid valve when the condensate level in the reservoir reaches the upper sensor switch and to close said solenoid valve when the condensate level falls to said lower sensor switch.

58. The method of claim 57, including the steps of utilizing the microprocessor to also continuously monitor the time required for the reservoir to fill with condensate from the low level sensor to the upper level sensor and to dump the condensate by connecting the electric circuit that powers the solenoid also to said microprocessor to input a signal to the microprocessor when the solenoid is turned on and off to actuate said valve closed and open, to use the volume of the reservoir and time of fill to calculate the rate of condensate flow into the reservoir, and utilizing that rate to calculate the volume of the next succeeding dump by multiplying the rate of inflow times the time of the dump and adding the product to the volume of the reservoir, and to output a signal to actuate a totalizer to register the volume of the dumps.

59. The method of claim 58, including the steps of monitoring the times the solenoid is actually actuated to open the valve and to close the valve during condensate dumps and air purges and comparing those times with predetermined acceptable reference times for these modes, and outputting a signal to actuate an alarm whenever any of these actual times exceed the predetermined reference times.