Humidifier with automatic drain interval determination

Abstract

With respect to atmospheric steam generating humidifiers, the present disclosure resolves the problem of end-users not adjusting the drain interval of the humidifier by using an electronic controller to automatically choose an appropriate drain interval without requiring any user input. The electronic controller accomplishes this by receiving input data from a sensor that measures a water quality parameter, automatically determining a drain interval based on the received data, and sending an output control signal to a drain water control valve to execute a drain event in accordance with the drain interval. In some examples, the electronic controller utilizes a look-up table correlating the water quality parameter to a total dissolved solids or cycles of concentration value.

Claims

1. An atmospheric steam generating humidifier comprising: a) an unpressurized water storage tank; b) a steam outlet extending from the water storage tank for allowing steam generated within the water storage tank to exit the water storage tank; c) a water drain outlet extending from the water storage tank to allow water to be drained from the water storage tank; d) a heating element for converting water stored within the tank to steam at atmospheric pressure; e) a drain water control valve in fluid communication with the water drain outlet; f) a water quality sensor located in the water storage tank and configured for sensing a water quality parameter associated with make-up water stored within the water storage tank during or after a fill event; and g) an electronic controller which receives input data from the water quality sensor during or after the fill event, determines a drain interval to drain the water storage tank based on input data received from the sensor relating to the quality of the make-up water, and sends an output control signal to the drain water control valve at the determined drain interval.

2. The atmospheric steam generating humidifier of claim 1, wherein the water quality sensor is a total dissolved solids meter and the water quality parameter is water total dissolved solids.

3. The atmospheric steam generating humidifier of claim 1, wherein the water quality sensor is an electrical conductivity probe and the water quality parameter is water electrical conductivity expressed in counts.

4. The atmospheric steam generating humidifier of claim 1, wherein the drain interval is based on one or more of an amount of steam generated by the humidifier, a number of tanks of steam generated by the humidifier, or cycles of concentration of the water within the tank.

5. The atmospheric steam generating humidifier of claim 1, wherein the electronic controller includes a look-up table correlating the water quality parameter to a cycles of concentration value or total dissolved solids of the tank.

6. The atmospheric steam generating humidifier of claim 5, wherein the electronic controller multiplies a volume of the tank by the cycles of concentration value to calculate the drain interval defined in terms of steam produced by the humidifier.

7. The atmospheric steam generating humidifier of claim 6, wherein the steam produced by the humidifier is expressed within the controller as pounds of steam generated or a number of tanks of water generated to steam.

8. The atmospheric steam generating humidifier of claim 1, wherein the sensor includes a plurality of sensors.

9. The atmospheric steam generating humidifier of claim 8, wherein the plurality of sensors includes three sensors having different lengths.

10. An atmospheric steam generating humidifier comprising: a) an unpressurized water storage tank; b) a steam outlet extending from the water storage tank for allowing steam generated within the water storage tank to exit the water storage tank; c) a water drain outlet extending from the water storage tank to allow water to be drained from the water storage tank; d) a heating element for converting water stored within the tank to steam at atmospheric pressure; e) a fill water control valve in fluid communication with an inlet of the water storage tank; f) a drain water control valve in fluid communication with the water drain outlet; g) a first water senor within the water storage tank for sensing a first water level within the water storage tank; h) a second water sensor within the water storage tank for sensing a second water level within the water storage tank different from the first water level; i) wherein one or both of the first and second water sensors is a water quality sensor for sensing a water quality parameter associated with water stored within the water storage tank; and j) an electronic controller which receives input data from the first and second water sensors after a fill event, determines a drain interval to drain the water storage tank based on input data received from at least one of the first and second water sensors relating to the quality of the stored water, and sends an output control signal to the drain water control valve at the determined drain interval.

11. The atmospheric steam generating humidifier of claim 10, wherein the water quality sensor is either: a) a total dissolved solids meter and the water quality parameter is water total dissolved solids; or b) an electrical conductivity probe and the water quality parameter is water electrical conductivity expressed in counts.

12. The atmospheric steam generating humidifier of claim 10, wherein the drain interval is based on one or more of an amount of steam generated by the humidifier, a number of tanks of steam generated by the humidifier, or cycles of concentration of the water within the tank.

13. The atmospheric steam generating humidifier of claim 10, wherein the electronic controller further comprises: a) a look-up table correlating the water quality parameter to a cycles of concentration value or total dissolved solids of the tank; and b) multiplies a volume of the tank by the cycles of concentration value to calculate the drain interval defined in terms of steam produced by the humidifier, wherein the steam produced by the humidifier is expressed within the controller as pounds of steam generated or a number of tanks of water generated to steam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:

(2) FIG. 1 is a schematic view of an atmospheric steam humidifier and control system having features that are examples of aspects in accordance with the principles of the present disclosure, the evaporative media system being usable in the air handling system shown in FIG. 1.

(3) FIG. 2 is a flow diagram for a control process for operating the steam humidifier shown in FIG. 1.

(4) FIG. 3 is a graphical depiction showing a general relationship between supply water electrical conductivity and the drain interval of the humidifier shown in FIG. 1.

DETAILED DESCRIPTION

(5) Various examples will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various examples does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible examples for the appended claims. Referring to the drawings wherein like reference numbers correspond to like or similar components throughout the several figures.

General Description

(6) Referring to FIG. 1, an atmospheric steam humidifier 10 and an electronic controller 500 for operating the humidifier 10 are presented. As shown, the humidifier 10 includes a water storage tank 12 defining an interior volume 14 for holding a volume of water 1. In one aspect, the water storage tank 12 includes a water inlet 16 such that the storage tank can be filled with make-up water. The water storage tank 12 also includes a drain outlet 18 such that water can be drained from the water storage tank 12. The water storage tank 12 further includes a steam outlet 20 through which steam generated within the water storage tank 12 can exit for delivery to a steam distribution system.

(7) The atmospheric steam humidifier 10 is also shown as including a heating element 50 disposed within the water storage tank 12. In one example, the heating element 50 is an immersed electric resistive heating element and the electronic controller 500 sends a signal to energize the heating element 50 to heat the water in the tank to generate steam. Heating element 50 can also be configured as a gas-fired heater, a steam-to-liquid heater, a liquid-to-steam heater, or an electrode-type heater.

(8) As steam is generated by the heating element 50, the water level drops in the tank 12 which results in the need for make-up water to be added to the tank. To add water to the tank 12, a make-up water valve 30 can be provided and controlled by the electronic controller 500. In one example, the control valve 30 includes a fast-fill control valve for rapid filling and a micro-fill control valve for more precise filling at a lower flow rate. In operation, the electronic controller 500 sends a command to open the make-up water valve 30 which allows water to enter the tank from a supply source via the water inlet 16 in the water storage tank 12.

(9) Water can also be drained from the tank through operation of a drain water control valve 40 commanded by the electronic controller 500. As is discussed in more detail later, water from the water storage tank 12 should be drained from the tank periodically to reduce scaling within the interior surfaces water storage tank 12. The drain water control valve 40 is in fluid communication with the tank drain outlet 18 such that when the electronic controller 500 commands the drain water control valve 40 to the open position, water is drained from the water storage tank 12.

(10) Sensors 60a, 60b, 60c (sensors 60) can also be provided within the water storage tank 12. The sensors 60 can be configured to provide data inputs to the electronic controller 500. In one application, sensor 60a can be used to identify a maximum-filled water condition to ensure that the make-up water valve does not fill the water storage tank 12 beyond a predetermined level. Likewise, sensor 60c can be used to identify a minimum-filled water condition to ensure that the water storage tank 12 has not been drained below a suitable level for operation and to ensure that the water storage tank 12 has been drained sufficiently during a draining operation. Sensor 60b can be used to determine a midpoint fill level in the tank 12. As is discussed in more detail later, the sensors 60 can also be used to measure the electrical conductivity of the water within the tank. In one example, one or all of the sensors 60 is configured as an electrical conductivity meter. In one example one or all of the sensors 60 is configured as a total dissolved solids (TDS) meter.

Control System

(11) With continued reference to FIG. 1, the humidifier 10 may also include an electronic controller 500. The electronic controller 500 is schematically shown as including a processor 500A and a non-transient storage medium or memory 500B, such as RAM, flash drive or a hard drive. Memory 500B is for storing executable code, the operating parameters, and the input from the operator user interface 502 while processor 500A is for executing the code. The electronic controller is also shown as including a transmitting/receiving port 500C, such as an Ethernet port for two-way communication with a WAN/LAN related to an automation system. A user interface 502 may be provided to activate and deactivate the system, allow a user to manipulate certain settings or inputs to the controller 500, and to view information about the system operation.

(12) The electronic controller 500 typically includes at least some form of memory 500B. Examples of memory 500B include computer readable media. Computer readable media includes any available media that can be accessed by the processor 500A. By way of example, computer readable media include computer readable storage media and computer readable communication media.

(13) Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any device configured to store information such as computer readable instructions, data structures, program modules or other data. Computer readable storage media includes, but is not limited to, random access memory, read only memory, electrically erasable programmable read only memory, flash memory or other memory technology, compact disc read only memory, digital versatile disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the processor 500A.

(14) Computer readable communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” refers to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, computer readable communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared, and other wireless media. Combinations of any of the above are also included within the scope of computer readable media.

(15) The electronic controller 500 is also shown as having a number of inputs/outputs that may be used for implementing the below described draining methods for maintaining water quality within the tank 12 such that scaling is minimized. As mentioned previously, electronic controller 500 provides outputs for energizing the heating element 50, an output for controlling the make-up water fill control valve 30, and an output for controlling a tank drain water control valve 40. Status inputs can be provided for each of the aforementioned control components as well. Additionally, inputs for tank water level and water conductivity via sensors 60 and tank water temperature (not shown) may be provided as well. The controller 500 can also include additional inputs and outputs for desirable operation of the humidifier 10 and related systems.

Process 1000

(16) In one aspect, the controller 500 may be programmed to execute an automatic drain control process 1000, as outlined at FIG. 2. The disclosed process 1000 solves the problem of end-users not adjusting the drain interval by using the electronic controller to automatically choose an appropriate drain interval. Electrical conductivity of water increases with mineral concentration. By measuring the electrical conductivity of the water, the mineral concentration is generally known thus allowing an appropriate drain interval to be selected. While there are scenarios, such as excessively high chlorides in supply water, where the best drain interval must still be determined by the end-user, for the majority of applications the automatically chosen drain interval will be superior to the default drain interval that inevitably remains in most humidifiers.

(17) In a step 1002, one or more of the sensors 60a, 60b, 60c (generically referred to as sensor 60) is a dedicated sensor for sensing a value of a water quality parameter. In one example, the sensor 60 is a total dissolved solids (TDS) meter and expresses the water quality parameter value in terms of total dissolved solids or electrical conductivity of the water. In one example, the sensor 60 is an electrical conductivity (EC) meter and expresses the water quality parameter value in terms of electrical conductivity. In a step 1004, the electronic controller 500 receives the water quality parameter value data from the sensor 60. In a step 1006, the electronic controller 500 automatically selects a drain interval based on the water quality parameter value received at the electronic controller 500. In one example, step 1006 includes referring to a look-up table that correlates the water quality parameter (e.g. conductivity, TDS) with a drain interval and selecting a drain interval corresponding to the sensed water quality parameter value. In one example, step 1006 includes using a formula defining a relationship (e.g. a curve) between the water quality parameter value (e.g. conductivity, TDS) and the drain interval, and calculating a drain interval based on inputting the sensed water quality parameter value. Referring to FIG. 3, a graph 80 is presented showing a general relationship between water electronic conductivity (i.e. water quality parameter) and a resulting drain interval. As can be seen, the drain interval increases with water electrical conductivity. In a step 1008, the electronic controller 500 operates the drain valve 40 in accordance with the selected or calculated drain interval.

(18) In a preferred embodiment, sensors 60 simultaneously serve as electrical conductivity probes used for detecting the water level within the water storage tank 12 and as water electrical conductivity sensors so appropriate drain intervals can be automatically selected by the electronic controller 500.

(19) Various methods exist regarding the details of measuring the water quality parameter (i.e. electrical conductivity) and controlling the drain intervals. For example, the supply water conductivity can be measured at step 1002 each time an empty tank is filled, following a complete tank drain event, or upon initial fill. The automatically selected drain interval at step 1006 determines when the next drain event occurs at step 1008. The drain interval can be based on pounds (lbs) of steam created by the humidifier 10, the number of tanks of water converted to steam, or cycles of concentration (COC). With the tank volume pre-programmed into the electronic controller 500, the tanks used or COC is easily determined by the electronic controller 500. For a further explanation of cycles of concentration, refer to U.S. Pat. No. 9,801,964 entitled Evaporative Cycles of Concentration Control and issued on Oct. 31, 2017, the entirety of which is incorporated by reference herein.

(20) In an alternative approach, a drain event can be initiated automatically based on a attaining a conductivity threshold of the tank water. Since the exiting steam is generally free of minerals, the mineral concentration and conductivity of the tank water steadily climbs during operation. Supply water with high mineral content will attain the conductivity threshold sooner (lower COC) than supply water with a low mineral content. In this manner water with higher conductivity/TDS results in an increased drain interval.

Automatic Drain Interval Determination Example

(21) In one example implementation of the disclosed humidifier 10 and process 1000, the electrical conductivity of water is determined using data from the water level sensing conductivity probes 60, which consist of 3 probe lengths, bottom (60c), middle (60b) and top (60a).

(22) Conductivity measurement (i.e. step 1002) for drain interval determination is taken while filling the tank, such as following a new installation, or after a drain event or upon filling the tank to resume humidification following an end-of-season drain (automatic drain after 72 hours of no humidification).

(23) While filling, once the bottom probe detects water, a fast fill valve is closed and a micro-fill valve remains open, thus reducing the fill rate to about 1/10. The water level slowly increases until just contacting the mid probe whereupon the conductivity measurement is immediately recorded by the electronic controller 500 (i.e. step 1004).

(24) This particular electronic water level sensing system produces a range of values, referred to as “counts”, from about 14,000 to 0 (i.e. a water quality parameter). The counts can be characterized to determine their relationship to room temperature waters of various conductivities in microsiemens/cm or μS/cm and Total Dissolved Solids (TDS). (2 μS/cm˜1 ppm of TDS.), as follows:

(25) ˜14,0000 counts=air=0 μS/cm of electrical conductance

(26) ˜7,000 counts=Typical deionized water (DI) ˜0.1 μS/cm=0.05 ppm TDS

(27) ˜4,000 counts=Reverse osmosis water (RO) ˜30 μS/cm=15 ppm TDS

(28) ˜1,500 counts=potable water/RO blend ˜70 μS/cm=35 ppm TDS

(29) ˜900 counts=typical tap water ˜200 μS/cm=100 ppm TDS

(30) ˜800 counts=well water ˜700 μS/cm=350 ppm TDS

(31) A look-up table can be developed that defines the drain rate, interval or maximum COC for multiple ranges of counts readings from the water level conductivity probes. This look-up table and the water capacity of the tank are programmed into the electronic controller 500. The electronic controller 500 can be configured to record the pounds (lbs) of steam created based on energy used by the humidifier 10. An example look-up table of count ranges and corresponding COC:

(32) >=7,000 counts=150 COC maximum

(33) <6,000 and >=2,500 counts=120 COC maximum

(34) <2,500 and >=1,200 counts=80 COC maximum

(35) <1,200 and >=800 counts=50 COC maximum

(36) <800 counts=20 COC maximum

(37) The electronic controller 500 then returns a drain rate, COC or drain interval for a tank capacity, for example a tank capacity of 100 pounds pounds of water. For purposes of illustration, in one example using the filling and sensing procedure described above, the controller 500 records 960 counts. Using the previously described look-up table programmed into the controller, a reading of 960 counts falls between the <b1,200 and >=800 counts range for a maximum COC of 50, which is retrieved from the look-up table and used to calculate the drain interval. The drain interval can be calculated by multiplying 50 COC by the tank capacity of 100 lbs of water, which yields a result of 5,000 lbs. This means that the mineral concentration will be concentrated to the maximum allowable COC of 50 after creating 5,000 lbs of steam or 50 tanks of water boiled off. The controller 500 can display to the end user that the tank will be drained every 5,000 lbs of steam created. Consequently, the controller 500 records the pounds of steam created based on energy used, and drains the tank after creating 5,000 lbs of steam, thus draining upon reaching the maximum COC of 50 (e.g. step 1008).

(38) Upon the next refill assume the probe counts change because the supply water source was changed to RO water and 3,600 counts is recorded upon filling as described using the previously described approach. The electronic controller 500 will then select a new drain rate per the table with COC of 120, thus replacing the previous drain rate COC of 50. The electronic controller 500 will then calculate a drain interval of 12,000 pounds of steam generation (120 COC×100 lbs tank capacity=12,000 lbs.). Therefore, every 12,000 lbs of steam created the tank will be drained. The RO water has a lower TDS content, therefore less draining is needed. Water and energy savings are thus realized with no impact to scale accumulation or corrosion. Additionally, slightly better performance is realized from fewer interruptions to steam production.

(39) As evidenced in the above example, the electronic controller 500 automatically determines the optimal drain interval for the humidifier 10 without requiring input from the user as to the nature of the water being supplied to the humidifier 10. Thus, the disclosed humidifier 10 and controller 500 represent an improvement over designs which require information inputted by a user for optimal operation.

(40) From the forgoing detailed description, it will be evident that modifications and variations can be made in the aspects of the disclosure without departing from the spirit or scope of the aspects. While the best modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims.