CH656944A5 - AUTOMATIC HUMIDIFICATION SYSTEM. - Google Patents

Description

The invention relates to an automatic air humidification system in which the operational safety and the lifespan of the evaporation cylinders are multiplied by taking into account the amount of water evaporated during the operation of the evaporation cylinder, as well as the amounts of water scale and other contaminants, for the purpose of periodically removing the same effective cleaning, or washing cycles can be switched in between.

The biggest problem with evaporation with direct heating is that the substances present in the supplied water (e.g. water stone or other contaminants) precipitate on the electrodes, the inner surface, the filter and the outlet elements during operation of the evaporation cylinder. If the precipitate is not removed regularly, completely and with the greatest care,

a coherent surface gradually emerges, which affects the effective surface of the electrodes and the outflow cross-section of the cylinder.

Detachment of the precipitated water stone layer using chemicals is not possible during operation based on the principle of direct heating.

In the currently commercially available systems, the principle of cylinder washing during operation is implemented in the Swedish Steamatic system alone, albeit with little effectiveness. In this system, the time of the periodically starting washing process can be set on the electromechanical time switch, whereupon the evaporation cylinder is filled with a water jet fed through a narrow cross section and then emptied.

In this solution, the principle of water stone detachment that can be achieved by a sudden change in temperature is not used; only the contamination present in the evaporating cylinder in a dissolved state can be removed here.

The disadvantage of this method is that the limestone which spontaneously detaches in pieces during operation accumulates in the cylinder and gradually reduces the flow cross-section.

In the course of the washing process, the completion of the water drainage following the replenishment is by no means indicated by a lower water level sensor. The duration is regulated by the set timer.

For example, Occasionally, if the flow cross section is already tapered, the evaporation cylinder cannot be completely emptied during the set emptying period and that contaminated water remains.

If such cases occur frequently, the contents of the evaporation cylinder gradually accumulate in dissolved impurities; in the end the plant becomes inoperable.

With the Steamatic system, efforts were made to reduce the defects described above by dismantling the evaporation cylinder and by performing the manual cleaning cycles according to the regulations. The problems related to operation mentioned here are evident in all systems which have an evaporation cylinder, with the only difference that the washing cycles in the Steamatic system offer the possibility of not having to carry out mechanical cleaning as often. For the sake of good order, it should also be noted that the mechanical cleaning processes following the malfunction or the cleaning process carried out beforehand can only be carried out when the system is out of operation, the frequency depending on the hardness of the water used or on the water used Degree of contamination depends.

In view of the fact that a system evaporates about 10 liters of water per hour during normal operation, the system also requires several cleaning processes per week, even if the drinking water is purely qualified.

The object of the invention was to eliminate the above-mentioned deficiencies by means of a control principle which has not been used until now.

The aim of the invention is therefore a control device which is used for the automatic, operation-dependent washing of the evaporation cylinders during the operation of the air humidification system, the washing cycle being regulated in function of the deposits which form, and the permanent deposits of various impurities on the walls of the cylinder , electrodes, etc. prevented.

The aim of the invention is achieved by an automatic air humidification system, which is characterized by the characterizing part of claim 1.

The invention is explained in more detail using an advantageous exemplary embodiment, with the aid of the accompanying drawings. Show it:

1 shows the new principle of cleaning the evaporation cylinder and the block diagram of the control electronics,

FIG. 2 shows the electrical circuit of the executive organs,

FIG. 3 shows the principle of operation of the “digital clock” that tempers the washing cycles,

Figure 4 shows the electrical perception of the lower and upper water levels in the evaporation cylinder.

As can be clearly seen from FIG. 1, the magnetic switch 10 is arranged in the main circuit 11 of the evaporation cylinder 1, and in addition the current transformer 12 is provided in the circuit of one phase. The magnetic switch 10 is assigned the task of disconnecting the main circuit during the washing process, while the current transformer 12 generates an analog voltage signal proportional to the current drawn by the cylinder and therefore to the amount of water present in the cylinder. Its output signal controls the s

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voltage-controlled oscillator 15. Together with the digital dividing chain 16, the oscillator forms a digital clock which always “goes” at a speed proportional to the amount of water fed into the cylinder.

In view of the fact that the impurities (water stone) leaving the cylinder are quantitatively proportional to the amount of water fed in, this proportionality is followed elastically by the digital clock; as a consequence, washing cycles are started at appropriate intervals.

If the output of the digital sub-chain 16 now switches to the high level, the circuit with the relay issues a command to clean the cylinder. The individual phases are as follows:

- The magnetic switch interrupts the main circuit of the cylinder.

- The washing valve 4 with a large cross section is opened. The cold water jet reaches the electrodes and the drain filter via the valve directly under the water pressure of the network and over a large cross-section. The precipitated water stone is loosened by the effect of the rapid temperature change, which means that it can be easily removed by means of the mechanical energy of the water jet.

- The water is filled up to the level determined by the upper level sensor.

- By filling the digital divider chain 16 is deleted, the washing valve 4 closes with the large cross section, and the circuit 17 with the relay gives a command to open the emptying solenoid valve 5 - whose diameter corresponds to the entire discharge cross section of the evaporation cylinder 1 - and a start signal for the oscillator 14 with the fixed frequency. The frequency of the oscillator 14 with the fixed frequency is selected such that, in the case of a completely pure drain filter and drain organs, the digital divider chain 16 counts until the third of the division during the period of emptying, this value being stored in the chain.

- The complete emptying of the cylinder is detected by the level sensor which senses the lower water level and which issues a command to the stop input of the oscillator 14 at the fixed frequency; A command to reset the magnetic switch 10 is issued via the circuit 17 with the relay.

The first wash cycle is now complete. In the subsequent evaporation cycle, the digital sub-chain continues to count - starting from the “filled-in state” down to the one-third part.

Furthermore, the interval between the individual washing cycles is determined by the “electrical length” of the two-thirds part remaining after washing, and by the frequency of the voltage-controlled oscillator 15, which frequency is proportional to the amount of water.

Should water stone become detached during operation of the evaporation cylinder and, as a result of the detachment or because of the water stone stored in the flow cross-section, the flow cross-section constricts, the evaporation cylinder empties much more slowly during the washing cycle than in a completely clean state. Thus the emptying period is lengthened, the divider chain is increasingly increased by the oscillator 14 with the fixed frequency, to a proportionally higher proportion - i.e. not just up to a third - «filled». The "pitch length" remaining for the next evaporation cycle is shortened, in other words, the system concentrates the number of washing processes in a proportion proportional to the formation of limestone.

With this simple feedback of the digital divider chain 16, it can be achieved that after reaching a predetermined extension of the emptying period, the washing cycle is repeated until the emptying period returns to the desired value.

Figure 2 shows the circuit controlling the washing process with the relay and the electrical circuit of the executive organs.

As soon as the last link of the digital divider chain in the BCD-lo code arrives when counting za the number 9, the circuit 17 becomes conductive with the relay: At the normally closed contact 17/2, the circuit of the magnetic switch 10 is interrupted, causing it to drop. The washing valve 4 with the large cross-section is controlled via the normally closed contact ls 10/5 and the operating contact 17/4, whereupon the water filling is started. The detector circuit 9 of the lower water level closes via the normally closed contact 10/1. The relay picks up considering that there is water in the evaporation cylinder. As soon as the water level reaches the upper water level sensor 13, the content of the digital divider chain 16 is deleted via the operating contact 13/1 and the relay 17 drops out. The circuit of the washing valve 4 with the large cross section is interrupted via the operating contact 17/4. The circuit 25 of the emptying solenoid valve 5 closes via the normally closed contact 17/3 and the operating contact 9/4. The oscillator 14 with the fixed frequency that registers the emptying time receives a start signal via the normally closed contact 17/1 and the operating contact 9/2. As soon as the evaporation cylinder has been emptied, the relay of the detector circuit 9 of the lower water level drops out. The circuit of the emptying solenoid valve is interrupted via the operating contact 9/4, after which the magnetic switch 10 35 which interrupts the main circuit of the evaporation cylinder switches back via the normally closed contacts 9/3 and 17/2. At the operating contact 9/2, the oscillator 14 degrades at the fixed frequency. At the operating contact 9/1, the condition of the repeated washing process when the emptying time is extended by a certain 40 degree stimulating feedback ceases.

Subsequently, the cylinder is filled up to the operating state by the magnetic valve (not shown here) which functions during the evaporation cycle, and the evaporation is started.

FIG. 3 shows the schematic structure of the current transformer 12, the oscillator that registers the emptying time

14 with the fixed frequency, the voltage-controlled oscillator 14 with the fixed frequency, the voltage-controlled oscillator 15 and the digital divider chain 16, the mutual connection of the same or the arrangement relative to the circuit with the relay.

The current transformer 12, the voltage controlled oscillator

15 and the oscillator 14 with the fixed frequency are well known from the specialist literature and represent a useful one

55 circuit arrangement. The attenuated output voltage of the converter 12 with the potentiometer is always proportional to the current flowing in the main circuit 11. The voltage-controlled oscillator 15 following the output forms the oscillator of the digital clock measuring the cycle duration during the evaporation cycle. The frequency thereof - resulting from the linear connection between the water present in the evaporation cylinder and the current drawn by the evaporation cylinder - is always proportional to the amount of water present in the 65 evaporation cylinder.

In the evaporation cylinder 1 is the amount of water stone precipitating during operation and

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other impurities are proportional to the amount of water; In this way, the digital clock formed from the voltage-controlled oscillator 15 and the divider chain 16 switches on the washing cycles in accordance with this proportionality in the operation of the cylinder.

The output of the voltage-controlled oscillator 15 connects via the OR gate 29 to the input of the divider chain 28 with the division ratio 106. The AND gate 30 is connected to the other input of the OR gate 29. This connects the input of the divider chain to the oscillator 14 which registers the emptying period at the fixed frequency if the H level is present at the output of the Schmitt trigger 31. The switchover to the H level via the debouncing elements RC takes place only during the emptying period, i.e. when the normally closed contact 17/1 is open and the operating contact 9/2 is closed.

The division of the divider chains 28 and 32 is 9-106 until the washing process is initiated. If just as many impulses arrive at the input, the tens divider counts exactly to nine. The outputs 20 QA and 21 QD switch to the high level, and the circuit 17 with the relay receives the control for starting the washing process via the subsequent AND gate 22 and the transistor 25, whereupon the water filling is started. As soon as the water level reaches the electrode of the sensor 13 which senses the upper level, the content of the divider chain is deleted via the operating contact 13/1, the debouncing elements RC and the Schmitt trigger 27. The relay in the circuit 17 drops out, but at the same time the sensor 9 which senses the lower level remains retracted.

Via the normally closed contacts 17/1 and 9/2, the coupling conditions of the oscillator 14 registering the emptying time come about with the fixed frequency.

The oscillator operates at a frequency at which, during the emptying period of the evaporation cylinder with the completely pure flow cross-section, the digital divider chain 16 exactly up to the one-third part, i.e. to 3 • 106 counts, this value being stored in the divider chain and in the subsequent evaporation cycle no excitation for a washing process takes place until the divider chain counts up 6-106 pulses from the output of the voltage-controlled oscillator and the content of the counter 32 is nine.

If water stone settles in the cylinder, the flow cross-section is reduced, which increases the emptying period. The number of seconds that the emptying period is extended, and the number of seconds — which correspond to the quotient of the frequencies of the oscillators 15 and 14 multiplied by the fixed frequency — that is, the time running until the next washing process is shortened.

The feedback based on the AND gate 23 and 24, the Schmitt trigger 26 and the operating contact 9/1 always stimulates repetitive washing processes when the original emptying time doubles, i.e. if, during the purge period, the content of the ten divider 32 reaches six. In this case, the outputs 18 QB and 19 QB switch to the high level, and a pulse from the high level reaches the nine-position control input of the ten divider. Now, the divider 32 initiates a repeated wash cycle that continues until the cylinder is cleaned enough to empty for a period of time that is half the original drain period.

FIG. 4 illustrates the principle of perceiving the upper and lower water levels during washing of the evaporation cylinder. Originally, the electrode of the sensor that detects the upper water level is built into the evaporation cylinder, while the lower water level is sensed with the aid of the electrode present in the metal tube 6 arranged next to the cylinder, the connection of the electrode to the cylinder being based on the principle of “communicating” Vessels ». In order to be able to also close the tube 6 at the top, it is connected to the steam connector of the cylinder, on the upper part, via the tube section 33.

In the course of evaporation, the heat generated by the ohmic resistance of the water in the cylinder heats the water. The conductivity of the water is also used to monitor the water level during the wash cycle. The water present in the switched-off cylinder is always at zero potential via the discharge elements or the pipe 6. The rectifiers of the level sensors which connect the phase line 11 to the other poles receive control from here by the interposition of the electrodes. After suitable filtering, the rectifier output feeds small current relays dimensioned for phase voltage.

The automatic cleaning system according to the invention largely eliminates the deficiency of the known systems. It is made up of modern electronic elements, neither maintenance nor monitoring nor the costly replacement of the evaporation cylinder is claimed.

The achievable extension of the lifespan of the cylinder can e.g. characterized in that, where previously the cylinder had to be cleaned by hand every second day and replaced at least every other week, the cylinder can be kept in operation for one year without any manual intervention.

The control according to the invention claims a single card 100 x 150 mm, the circuits with the relays can be arranged in a capsule in the dimension 200 x 70 x 50 mm. The production costs are in no way higher than the purchase price of a single evaporation cylinder.

The automatic system can be easily adapted to existing systems that are already in operation.

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2 sheets of drawings

Claims (2)

656 944 2 PATENT CLAIMS 1. Automatic air humidification system, characterized in that for cleaning the interior of an evaporation cylinder (1) on the upper part of the evaporation cylinder, a washing valve (4) is provided, the valve is connected to a pipe (7) for the supply of cold water, further the The system contains an upper and a lower water level sensor (9, 13), one of the current transformers (12) connected to one phase of the main circuit (11), and a voltage-controlled oscillator (15) connected to the same, that the voltage-controlled oscillator (15) has a digital divider chain ( 16) is connected downstream, a circuit (17) with relay is also included, and that the digital divider chain (16), the upper water level sensor (13) and an oscillator (14) with a fixed frequency are electrically connected to the lower water level sensor (9) . 2. Automatic air humidification system according to claim 1, characterized in that the electrode of the lower water level sensor (9) is arranged in a tube (6) connected in parallel with the evaporation cylinder.