Stimulating device for enhancing release of negative air ions by a plant, and plant-based negative air ion producing device

A stimulating device for enhancing release of negative air ions by a plant includes a plant pot to receive a culture medium for cultivating the plant, and a negative voltage pulse module that outputs a negative voltage pulse to stimulate the plant via a pair of first and second conductive terminals. The first conductive terminal contacts the culture medium. The second conductive terminal is non-contact with the culture medium when the culture medium is placed in the plant pot.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 103112681, filed on Apr. 7, 2014.

FIELD

The disclosure relates to a negative air ion producing device, and more particularly to a plant-based negative air ion producing device.

BACKGROUND

The concentration of negative air ions (NAI) is an important index for evaluating air quality. Therefore, purely electrical NAI generators have been developed for indoor air purification. The NAI generated by such devices are different from plant-sourced NAI, which may be more beneficial to health. However, under an ordinary environment, the ability of a plant to release NAI is too weak to achieve a satisfactory NAI concentration.

SUMMARY

Therefore, an object of the disclosure is to provide a stimulating device for enhancing release of negative air ions by a plant.

According to one aspect of the disclosure, the stimulating device includes a housing, a plant pot, first and second conductive terminals and a negative voltage pulse module. The housing includes a first surrounding wall that defines an inner chamber. The plant pot is disposed in the inner chamber, and is configured to receive a culture medium for cultivating the plant. The first conductive terminal passes through the plant pot for contact with the culture medium. The second conductive terminal is spaced apart from the first conductive terminal, is disposed on one of the housing and the plant pot, and is to be non-contact with the culture medium when the culture medium is placed in the plant pot. The negative voltage pulse module is disposed on the housing, includes a first electrode electrically coupled to the first conductive terminal, and a second electrode electrically coupled to the second conductive terminal, and is configured to output a negative voltage pulse at the first electrode so as to stimulating the plant via the culture medium for enhancing release of the negative air ions thereby.

Another object of the disclosure is to provide a plant-based negative air ion producing device.

According to another aspect of the disclosure, the plant-based negative air ion producing device includes a housing, a plant pot, a culture medium, a plant, first and second conductive terminals and a negative voltage pulse module. The housing includes a first surrounding wall that defines an inner chamber. The plant pot is disposed in the inner chamber. The culture medium is disposed in the plant pot. The plant is cultivated in the culture medium and releases negative air ions. The first conductive terminal passes through the plant pot for contact with the culture medium. The second conductive terminal is spaced apart from the first conductive terminal, is disposed on one of the housing and the plant pot, and is to be non-contact with the culture medium. The negative voltage pulse module is disposed on the housing, includes a first electrode electrically coupled to the first conductive terminal, and a second electrode electrically coupled to the second conductive terminal, and is configured to output a negative voltage pulse at the first electrode so as to stimulating the plant via the culture medium for enhancing release of the negative air ions thereby.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 4, the first embodiment of the plant-based negative air ion (NAI) producing device according to this disclosure is shown to include a stimulating device that includes a housing1, a plant pot2filled with a culture medium (e.g., soil, culture liquid, etc.) in which a plant100may be cultivated, a first conductive terminal22, a second conductive terminal14and a negative voltage pulse module3. The housing1has a first annular surrounding wall12that defines an inner chamber121, a second annular surrounding wall11that surrounds the first annular surrounding wall12, and an interconnecting wall13that interconnects bottom parts of the first and second annular surrounding walls12,11. In this embodiment, the first conductive terminal22passes through a bottom of the plant pot2for contact with the culture medium. The second conductive terminal14is disposed on the interconnecting wall13of the housing1, and is exposed in the air and non-contact with the culture medium when the culture medium is placed in the plant pot2. In addition, the housing1may further include a seat15separably disposed under the interconnecting wall13for accommodating the negative voltage pulse module3therein. In one embodiment, the second conductive terminal14may be disposed on the plant pot2and is non-contact with the culture medium when the culture medium is placed in the plant pot2.

Referring toFIG. 1, in this embodiment, the plant100cultivated in the plant pot2belongs to Agavoideae, and is for example, Agave Americana. The plant of the Agavoideae subfamily is superior in the ability to release NAI, drought resistance, shade resistance, etc., has a long life span (which may lead to longer time NAI release period), and grows well indoors. High negative voltage pulses applied to the first conductive terminal22(seeFIGS. 2 and 4) may stimulate a root portion of the plant100via the culture medium, thereby enhancing release of NAI by the plant100. In one embodiment, the high negative voltage pulses may range between −4 KV and −20 KV and are applied with a frequency ranging between 0.5 Hz and 2 Hz.

Referring toFIG. 2, in this embodiment, the housing1further includes an annular bearing plate17that is separably mounted to the first annular surrounding wall12, that has an annular plate portion173disposed between the first and second annular surrounding walls12,11and above the interconnecting wall13, and a central opening171corresponding in position to and in spatial communication with the inner chamber121. The plate portion173of the bearing plate17cooperates with the first annular surrounding wall12, the second annular surrounding wall11and the interconnecting wall13to form an outer chamber16thereamong, as shown inFIG. 4.

Further referring toFIG. 4, in this embodiment, the bearing plate17has an annular engaging portion172that has an inverse-V-shaped cross section, and that is hookably engaged with the first annular surrounding wall12. In one embodiment, an outer peripheral part of the bearing plate17protrudes away from the interconnecting wall13and abuts against an inner surface of the second annular surrounding wall11, such that the bearing plate17may be firmly mounted above the interconnecting wall13. When the plant pot2is placed in the inner chamber121, a peripheral edge portion of the plant pot2that surrounds a top opening23of the plant pot2abuts against a top part of the engaging portion172. The first annular surrounding wall12together with the annular engaging portion172may provide sufficient structural strength for holding the plant pot2hanging in the inner chamber121.

Referring toFIGS. 1-3, a bottom surface of the bearing plate17is formed with a plurality of through holes174for helping securing the other plants that may be cultivated in the outer chamber16.

Referring toFIG. 5, the negative voltage pulse module3of this embodiment includes a controller31, an optical coupler32electrically coupled to the controller31, a driving circuit33electrically coupled to the optical coupler32, a voltage pulse generating circuit34coupled to the driving circuit33, and a pair of first and second electrodes301,302. In one embodiment, the controller31may be implemented using an STC11 series single-chip microcontroller. The controller31may be configured, according to an activation signal associated with an NAI concentration and a continuous duration of NAI release stimulation that are set via a remote controller4or a keyboard (not shown), to execute table look-up instructions and time setting instructions and output a first control signal, such as a 5V pulse signal, based upon parameters obtained by execution of the instructions. The first control signal is transmitted to the driving circuit33via the optical coupler32, which may provide good noise isolation between the controller31and the driving circuit33. The driving circuit33has a half-bridge chip331that rectifies and amplifies the first control signal received from the optical coupler32to provide a 5V pulse signal with a large current, thereby driving a MOSFET switch332to output to the voltage pulse generating circuit34a 12V modulation driving signal with a large driving current. The voltage pulse generating circuit34includes a boost converter (T) that boosts a voltage level of the driving signal, and a rectifier circuit340that rectifies the boosted driving signal, so as to output the negative high voltage pulse to the first and second electrodes301,302, which are respectively coupled to the first and second terminals22,14(seeFIG. 2). The root portion of the plant100is then stimulated by the negative high voltage pulse via the culture medium and the first and second terminals22,14, thereby releasing NAI more efficiently. Since the housing1and plant pot2on which the first and second terminals22,14are disposed are not electrically coupled together, a virtual loop is formed via air between the first and second electrodes301,302that have no direct electrical connection therebetween, and the plant100releases NAI to the air. In this embodiment, the negative voltage pulse module3further includes a remote signal receiving circuit35configured to receive signals (e.g., the activation signal) from the remote controller4.

The boost converter (T) of the voltage pulse generating circuit34includes a primary-side coil (N1) and a secondary-side coil (N2). The primary-side coil (N1) has a first terminal electrically coupled to the driving circuit33for receiving the driving signal therefrom, and a second terminal electrically coupled to a direct current voltage source342via a resettable fuse341. When overcurrent occurs in the primary-side coil (N1), a resulted high temperature may cause the resettable fuse341to enter a non-conductive/electrically-isolating state, thereby protecting circuits from damage due to the overcurrent. Upon termination of the overcurrent and when the temperature becomes lower, the resettable fuse341may return to a conductive state. The secondary-side coil (N2) has a first terminal electrically coupled to the first electrode301, and a second terminal electrically coupled to a cathode of a diode (D) that has an anode electrically coupled to the second electrode302.

In this embodiment, the negative voltage pulse module3further includes a first resistor (R1) through which the first control signal is provided from the controller31to the optical coupler32, and a second resistor (R2) electrically coupled between ground and a common node of the first resistor (R1) and the controller31. The voltage division by the first and second resistors (R1), (R2) may effectively constrain a current flowing into the optical coupler32at the time of activation, thereby preventing the optical coupler32from damage due to an excessively high voltage provided by the controller31.

When the root portion of the plant100is stimulated by the high negative voltage pulse, electrical discharge may occur at leaf tips of the plant100. In order to prevent persons/animals from being frightened upon touching the leaf tips, the negative voltage pulse module3of this disclosure may further include at least one proximity sensor36(e.g., an ultrasonic proximity sensor) disposed on, for example, the second annular surrounding wall11of the housing1, and electrically coupled to the controller31, as shown inFIGS. 3 and 5, to thereby form an ultrasonic fence around the plant100. When the proximity sensor36senses the presence of an object within a predetermined distance range, e.g., a 20 cm range, the proximity sensor36generates a second control signal that is provided to the controller31and that causes the controller31to stop output of the first control signal, so that the driving circuit33stops driving the voltage pulse generating circuit34to generate the negative high voltage pulse. In this embodiment, multiple proximity sensors36that are disposed apart from each other on and around the second annular surrounding wall11are provided.

Even if the voltage pulse generating circuit34stops output of the negative high voltage pulse, electric charges may remain on the leaf tips of the plant100. In order to further prevent persons/animals from being frightened upon touch, the voltage pulse generating circuit34may further include a third resistor (R3) electrically coupled between the first and second electrodes301,302. By virtue of the third resistor (R3), the remaining electric charges may be discharged through a discharging loop formed by the first electrode301, the third resistor (R3) and the second electrode302, thus preventing occurrence of electric shocks. In one embodiment, the third resistor (R3) has a resistance of 1100 M ohms.

In this embodiment, the stimulating device further includes a temperature and humidity sensor37, a humidifier38(including a humidifier control circuit), and a fan device39(including a fan control circuit) that are disposed on the housing1and are electrically coupled to the controller31. The temperature and humidity sensor37provides to the controller31a set of ambient temperature and humidity values sensed thereby. The controller31may control, according to a difference between a set of preset temperature and humidity values and the set of ambient temperature and humidity values sensed by the temperature and humidity sensor37, operation of the humidifier38and a speed and a direction of wind provided by the fan device39, to thereby make the ambient temperature and humidity approach the preset temperature and humidity values, which is usually set as being suitable for the presence of NAI.

In this embodiment, the humidifier38and the fan device39are disposed above the plant pot2, and a spray outlet of the humidifier38faces toward a front side of the stimulating device, so that the spray provided by the humidifier38may be directly blown into the air by the fan device39, thereby avoiding adhesion of the spray on the stimulating device which may otherwise lead to safety concerns, such as current leakage.

In this embodiment, the stimulating device further includes an NAI detector51that detects a concentration value of ambient NAI and that is electrically coupled to the controller31for providing thereto the concentration value of ambient NAI thus detected. The controller31may determine, according to a difference between a preset concentration value of NAI and the concentration value of ambient NAI detected by the NAI detector51, whether or not to generate the first control signal, to thereby maintain the concentration of ambient NAI within an appropriate range. The temperature sensor37, the humidifier38, the fan device39and the NAI detector51may be integrated as a spatial NAI homogenizing device.

According to experiments, when the second annular surrounding wall11is spaced apart from the plant pot2by a distance that ranges between 50 mm and 200 mm such that the first and second electrodes301,302are not electrically coupled together through connection between the housing1and the plant pot2(seeFIG. 6), the NAI concentration measured at a location about 1 meter apart from the housing1is approximately 50,000 ions/cm3. On the other hand, when the first and second electrodes301,302are electrically coupled together via a wire between the housing1and the plant pot2(seeFIG. 7), the NAI concentration measured at the same location is approximately 3,000 ions/cm3. It is thus apparent that by virtue of the plant pot2being disposed in the inner chamber121of the housing1, making the first and second electrodes301,302not having direct electrical connection therebetween, the plant100may release NAI more efficiently, thereby promoting indoor NAI concentration.

FIG. 8is a graph showing a record of the NAI concentration resulting from a pot of Agave americana stimulated by the negative high voltage pulse using the embodiment of the stimulating device according to this disclosure.

Referring toFIG. 9, in the second embodiment of the NAI producing device of this disclosure, the housing1may be configured for placing, in addition to the plant pot (not shown) configured for NAI release stimulation (e.g., a plant pot2in which a plant of the Agavoideae subfamily is cultivated, as shown inFIG. 1), multiple planters (not shown) each being smaller than the plant pot. Note that the planters may be used to cultivate plants of the Agavoideae subfamily or other kinds of plants therein. The second embodiment further differs from the first embodiment in that in lieu of the central opening171and the through holes174(seeFIG. 2), the bearing plate17′ has a primary opening175that is spatially connected to the inner chamber121and that is configured for holding the plant pot, and multiple smaller secondary openings176that are configured for holding the planters. Each of the secondary openings176is in spatial connection with the outer chamber16, so that a respective planter may be held in the outer chamber16. In this embodiment, the secondary openings176are arranged in a vicinity of the primary opening175.

In summary, by virtue of the first and second conductive terminals22,14that are respectively disposed on the plant pot2and the housing1and that have no direct electrical connection therebetween, a virtual loop may be formed via the air between the first and second electrodes301,302, thereby stimulating the plant100to enhance its NAI release, so as to promote indoor NAI concentration. In addition, the design of the proximity sensor36and the third resistor (R3) may prevent persons/animals from suffering electric shocks when touching the plant100. Through the design of the temperature and humidity sensor37, the humidifier38, the fan device39and the NAI detector51, the ambient NAI concentration may be properly adjusted via the controller31, to thereby maintain the ambient NAI concentration within an appropriate range, and air quality may thus be improved.