Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B1/00—Methods of steam generation characterised by form of heating method
  • F22B1/28—Methods of steam generation characterised by form of heating method in boilers heated electrically
  • F22B1/284—Methods of steam generation characterised by form of heating method in boilers heated electrically with water in reservoirs
  • F22B1/285—Methods of steam generation characterised by form of heating method in boilers heated electrically with water in reservoirs the water being fed by a pump to the reservoirs

Definitions

• the present invention relates to a process for restoring the level of water in boilers of steam generating machines.
• the invention applies to the steam generating machines to be associated with various appliances such as flatirons, cleaning devices, air humidifiers, etc., and is directed to obtain a controlled and precise filling of the boiler in order to ensure that the functioning of the steam generator is always in condition of best efficiency.
• Steam generators are known incorporating a boiler constituted by an hermetically closed container tank, provided with heating resistors having the function of transforming the water into steam.
• the known boilers normally have a level sensor which provides to disconnect the resistors as soon as the level of the water reaches a predetermined minimum level, as well as to signal to the user such condition so that he can provide for the manual filling of the boiler.
• Such an automatic refilling or supply of additional water does not provide to fill the boiler for the whole or for the most part of its capacity, as it normally happens by the manual filling, but provides for the introduction of a little quantity of water to ensure that the temperature in the boiler does not drop substantially because of the introduction of a great quantity of cool water.
• Such a solution has the advantage, as said before, to spare the waiting times between the fillings of the boiler and to avoid the manual filling, but has the disadvantage that just a part of the power of the resistor is used to generate steam, since part of said power is used to heat the new cool water which, even if in little quantities, is each time introduced by the pump.
• the generator using such an automatic refilling system is able to generate less steam than a generator with a manual refilling in which, once the water has reached the evaporation temperature, the whole power is used to generate steam.
• a generator equipped with a manual refilling system has the disadvantage of the waiting times necessary to make said refilling.
• Object of the present invention is therefore to provide for a process for the restoring the level of water in boilers of steam generating machines which consents to control the operation of the pump and to guarantee with extreme precision, and under any circumstance, the reaching of the desired level of water within the boiler.
• the invention foresees the use of an auxiliary tank through which the boiler is filled by controlled operation of the restoration pump.
• the functioning of the pump is operatively connected with a pressure measuring device arranged at the interior of the boiler; said measuring device is normally a component with which the boiler is usually provided.
• the signal of the instantaneous pressure in the boiler controls the functioning of the pump, which changes its flow rate features according to said pressure and according to the typology of the pressure flow rate curve typical of the kind of pump used.
• the correction of the pump flow rate features according to the pressure can occur with the desired frequency according to the continuous changing of the pressure itself as the restoring stage (refilling with water) goes on.
• the water quantity fed into the boiler is constantly and substantially continuously checked, assuring with extreme precision the reaching of the desired level and so ensuring working conditions always optimal of the appliance connected to the steam generating machine.
• a flow rate reader connected in feedback to the pump control system.
• the real flow rate of the pump is continuously checked and the changes in said flow rate due to the pressure unstable conditions within the boiler are corrected in feedback by acting on the pump control system to constantly obtain controlled filling conditions.
• the pump is operatively connected to a maximum level sensor providing for its disconnection as soon as said maximum level is reached.
• Figure 1 schematically shows the means for carrying out the process for restoring the level of water in boilers of steam generating machines according to the invention
• Figure 2 shows a modified embodiment of the invention.
• reference numeral 10 indicates generically a detail of a steam generating machine using the process for restoring the level of water in the boiler 11 , according to the invention.
• Said machine 10 includes a water containing auxiliary tank 12 connected to a pump 13 connected to the boiler 11 through an inlet 14.
• the water of the tank 12 is introduced, at command, through the pump 13 to fill the boiler 11 , where it is progressively heated and then led to evaporation by the electric heating resistor 15 to generate steam which is supplied to the appliance (not shown) through the delivery outlet 16.
• the pump 13 is automatically operated, by a starting and control device 17, any time the water in the boiler 11 reaches a predetermined minimum level L0 which is calculated in such a manner to maintain the electric resistor 15 always submerged.
• the reaching of said minimum level L0 is detected by the same inlet conduit 14 which acts as conduction probe as the water level reaches its lower edge 18.
• the operation of the pump 13 is operatively controlled by the pressure measuring device 19 which, by utilising the continuously detected value of the pressure inside the boiler 11 , controls the pump 13, through said starting and control device, to cause the said pump to modify its flow rate according to the value of said pressure.
• the flow rate of the pump 13 is in fact variable depending upon the variation of the pressure in the boiler 11 and changes continuously, during the refilling operations, according to the variation of the quantity of water contained in the boiler 11.
• the control of the flow rate of the pump 13 according to the pressure in the boiler 11 allows to ensure under any circumstance and at any time the control of the filling conditions, by modifying the time of operation of the pump 13 to ensure the exact reaching of the maximum level L1.
• said variation occurs with a desired frequency, for instance every second, also depending upon the mechanical features of the pump 13.
• an instantaneous flow rate reader 21 on the feeding duct connecting the pump 13 to the boiler 11 there is arranged an instantaneous flow rate reader 21.
• Said reader 21 continuously detects the real instantaneous flow rate of the pump 13, as it changes according to the pressure within the boiler 11 , and controls in feedback the starting and control device 17 in such a manner that it modifies the delivery features of the pump 13 in order to obtain the desired and precise filling under any operating condition.
• a level sensor 22 connected in feedback to the control and activation system 17, which provides to stop the pump 13 as soon the level L1 is reached.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Steam Boilers And Waste-Gas Boilers (AREA)
• Control Of Non-Electrical Variables (AREA)
• Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
• Engine Equipment That Uses Special Cycles (AREA)
• Jet Pumps And Other Pumps (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11422470

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (3)

Citations (4)

• 1997
  • 1997-09-30 IT IT97UD000173A patent/IT1295505B1/it active IP Right Grant
• 1998
  • 1998-09-08 DE DE69808955T patent/DE69808955T2/de not_active Expired - Lifetime
  • 1998-09-08 AU AU95384/98A patent/AU9538498A/en not_active Abandoned
  • 1998-09-08 AT AT98948940T patent/ATE226704T1/de not_active IP Right Cessation
  • 1998-09-08 EP EP98948940A patent/EP1019655B1/de not_active Expired - Lifetime
  • 1998-09-08 ES ES98948940T patent/ES2184325T3/es not_active Expired - Lifetime
  • 1998-09-08 WO PCT/EP1998/005728 patent/WO1999017056A1/en active IP Right Grant
• 2000
  • 2000-04-27 HR HR20000246A patent/HRP20000246B1/xx not_active IP Right Cessation

Patent Citations (4)

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