Fumigating equipment and fumigating method

Abstract

According to one example of the present disclosure, a fumigating apparatus includes a mixing chamber having a first inlet and a second inlet. A gas conditioner, pump, or compressor directs a flow of non-flammable gas along a first passage from a non-flammable gas source through or through a heater to the first inlet of the mixing chamber, and a chemical pump directs a flow of chemical fumigant along a second passage from a chemical fumigant source to a second inlet of the mixing chamber. The temperature sensor measures the temperature of the mixed flow of hot gas and chemical fumigant at the outlet of the device. A controller controls the gas conditioner, pump or compressor, and / or the chemical agent pump based on the temperature measured by the temperature sensor to maintain the hot gas and chemical fumigant flow exiting the fumigating apparatus outlet at a predetermined temperature or higher.

Description

Technical Field

[0001] This disclosure relates to a fumigation device and a fumigation method. Background Technology

[0002] Fumigants are volatile chemical substances or toxic gases, typically produced from liquid and / or solid reagents. They possess bactericidal, fungicidal, insecticidal, and / or nematicidal properties and are used to kill or control pests, pathogens, and weeds. Fumigation is a technique for distributing and applying gaseous substances into enclosed spaces, particularly for the purpose of eliminating, controlling, or eradicating harmful organisms.

[0003] Fumigants are active in the gaseous state and can penetrate into the interior of agricultural products and the surrounding free air at toxic concentrations. They can also seep into cracks and crevices in storage structures and enclosed spaces, thereby killing target organisms and their reproductive stages. Fumigants are widely used for the prevention or control of insects, rodents, and fungi in stored products, food, cut flowers, timber, buildings, and soil due to their universal effectiveness and relative inexpensiveness.

[0004] Food products such as fruits and grains are particularly vulnerable to invertebrate pests. Some economic regions (such as Australia) have a 'zero-tolerance' policy for live insects in exported products to protect the reputation of local agricultural products. These regions typically employ extensive fumigation practices to reduce the risk of pest infestation. Equipment and facilities can also be susceptible to pest infestations and can be controlled through fumigation. Similarly, buildings, ships, containers, fruit trees, timber, and soil may require fumigation to control various pathogens and pests.

[0005] A wide range of chemicals can be used as fumigants for fumigation purposes, including hydrogen cyanide, calcium cyanide, carbon dioxide, sulfur dioxide, carbon tetrachloride, dichloroethane, ethyl formate, vinyl bromide, p-dichlorobenzene, 1,3-dichloropropene, chloropicrin, formaldehyde, methyl isocyanate, phosphine, methyl bromide, and sulfuryl fluoride. Each of these agents has certain advantages and disadvantages, including hazards related to toxicity and flammability.

[0006] Methyl bromide and phosphine are two chemicals commonly used for fumigation to control or prevent invertebrate pest infestations. Methyl bromide is a broad-spectrum insecticide with non-specific toxicity to many invertebrates. However, exposure to high concentrations can have harmful effects on humans and other animals. Another drawback of methyl bromide is that it is now widely recognized as a known and significant ozone-depleting substance. The detrimental effects of artificially adding methyl bromide to the atmosphere through fumigation on the ozone layer are well-known and documented. Nevertheless, methyl bromide remains a preferred fumigant for many quarantine agencies.

[0007] Phosphine is commonly used for fumigating grains and other similar commodities, and it is effective when used correctly. However, reports of phosphine resistance are increasing due to improper application and over-reliance. Some regions, which rely almost entirely on this single fumigant throughout the value chain, are at risk of developing phosphine resistance and require phosphine resistance monitoring and management programs.

[0008] Ethyl formate is an agent with properties indicating its suitability for use as a fumigant, particularly for the control of invertebrates. Ethyl formate vapor has been shown to be toxic to common stored commodities infested with insects. Ethyl formate is a naturally occurring compound found in various foods and rapidly decomposes into harmless, naturally occurring compounds. Although ethyl formate can be absorbed by the human body through inhalation of its vapors and through ingestion, skin, and / or eye contact, its toxicity to humans is relatively low. These characteristics indicate its suitability for food handling.

[0009] Ethyl formate is a liquid at normal ambient temperature with a boiling point of 54°C; however, it is highly flammable, with a lower explosive limit (LEL) of 2.8% (v / v) or 92 g / m³. -3 This poses a significant problem in the practical use of ethyl formate as a fumigant, as conditions that could ignite a flame must be avoided. Other fumigants used to control invertebrates, such as dichloroethane and propylene oxide, also present similar flammability issues when used as fumigants.

[0010] Fumigation is inherently a hazardous operation because the chemicals used in fumigation are generally toxic to most life forms (and in some cases, humans). The use of flammable agents increases the risk because, in order to apply a liquid agent as a fumigant, the agent must be converted from liquid to gas, typically via a vaporizer that requires heat. The use of liquid agents without vaporization is undesirable because the unvaporized agent content can cause occupational health and safety problems and / or damage to goods treated with the agent.

[0011] Therefore, the application of flammable agents as fumigants requires careful handling to minimize the risk of fire. It is known that mixing liquid reagents and non-flammable gases in cylinders under high pressure creates non-flammable formulations. However, using gases in cylinders has the disadvantage of potentially causing icing of the vaporizer, especially in cold or humid environments. This effect can significantly increase application time when the cylinder and regulator are frozen. Furthermore, if pressurized fumigants are used, well-trained fumigant operators appropriately trained in handling high-pressure cylinders must be employed to apply the fumigant.

[0012] It is also known that by combining liquid fumigants with carbon dioxide, fumigants that are substantially non-flammable can be produced under high pressure. Providing sufficient amounts of carbon dioxide can render flammable liquids non-flammable. However, these mixtures have all the limitations associated with the use of pressurized tanks, as well as additional limitations due to carbon dioxide, greenhouse gas emissions, phytotoxicity to fresh fruits and vegetables, and adverse degradation or corrosion of some materials. These difficulties limit the scope of use of such mixtures.

[0013] Existing vaporizer designs demonstrate variability in heating liquid reagents, leading to incomplete or partial vaporization. This can result in inefficient and ineffective reagent application, including uneven distribution of reagent throughout the treatment area and / or damage to cargo due to the settling of unvaporized reagent. Known vaporizer designs are also typically limited to single batches or limited volumes of liquid reagent within the chamber. The chamber must be refilled with liquid reagent before further application can be made, usually requiring a shutdown and a cooling period between applications. Therefore, improvements to fumigation techniques are needed to expand the range of reagents that can be safely and effectively used for fumigation and to mitigate various operational inefficiencies and safety hazards.

[0014] Any discussion of documents, actions, materials, devices, articles, etc., already included in this specification shall not be construed as an admission that any or all of such content constitutes part of the prior art or is common general knowledge in the field related to this disclosure, simply because it existed prior to the priority date of each claim of this application.

[0015] Throughout this specification, the word “comprise” or variations such as “comprises” or “comprising” should be understood to imply inclusion of the stated elements, integers or steps or groups of elements, integers or steps, but not to exclude any other elements, integers or steps or groups of elements, integers or steps. Summary of the Invention

[0016] In view of the above, according to a first aspect of this disclosure, a fumigation apparatus is provided, comprising: a mixing chamber including a first inlet, a second inlet, and a mixing chamber outlet, the first inlet for receiving a hot gas stream, the second inlet for receiving a chemical fumigant stream, and the mixing chamber outlet for discharging a mixed stream of hot gas and chemical fumigant; a gas regulator, pump, or compressor for guiding a non-flammable gas stream from a non-flammable gas source along a first channel to the first inlet of the mixing chamber; a heater for heating the non-flammable gas stream in the first channel to provide a hot gas stream to the first inlet of the mixing chamber; and a chemical pump. The chemical agent pump is used to guide a chemical fumigant flow along a second channel from the chemical fumigant source to the second inlet of the mixing chamber; a fumigation equipment outlet, which is in fluid communication with the mixing chamber outlet, for spraying the hot gas and chemical fumigant mixture flow; a temperature sensor, which is used to measure the temperature of the gas and chemical fumigant mixture flow leaving the fumigation equipment outlet; and a controller, which is used to control the gas regulator, pump or compressor and / or the chemical agent pump based on the temperature measured by the temperature sensor, to maintain the hot gas and chemical fumigant flow leaving the fumigation equipment outlet at a predetermined temperature or higher.

[0017] The device may further include a gas flow meter for measuring the flow rate of the gas flow in the first channel, and wherein the controller is configured to control the gas regulator, pump or compressor and / or the chemical pump based at least in part on the flow rate measured by the gas flow meter.

[0018] The controller can implement a negative feedback loop to control the gas regulator, pump, or compressor to dynamically adjust the flow rate of the gas passing through the first channel to maintain the output temperature of the hot gas and chemical fumigant mixture at the predetermined temperature or higher. The controller is configured to control the gas regulator, pump, or compressor based on the temperature measured by the temperature sensor, and the chemical pump is independent of the temperature measured by the temperature sensor and / or the flow rate of the gas stream measured by the gas flow meter. The temperature of the hot gas and chemical fumigant stream exiting the fumigation equipment outlet may be lower than the temperature of the heater.

[0019] In some instances, the controller is configured to control the gas regulator, pump, or compressor such that for every 3 liters of chemical fumigant pumped through the second channel, 4,500 to 6,000 liters of gas flow through the first channel.

[0020] In some instances, the second inlet of the mixing chamber includes a nozzle for atomizing the liquid chemical agent entering the mixing chamber. The nozzle may be a hydraulic atomizing nozzle.

[0021] In some instances, the first inlet of the mixing chamber is located at a first end of the mixing chamber, and the second inlet of the mixing chamber is located at a second end of the mixing chamber opposite to the first end, such that the hot gas flow and the chemical agent flow enter the mixing chamber from opposite directions, thereby generating turbulence. The mixing chamber outlet may be located on a sidewall engaging with the first and second ends of the mixing chamber, such that the hot gas and chemical fumigant mixture flows through the outlet and exits the mixing chamber in a direction substantially perpendicular to the direction in which the hot gas flow and the chemical agent flow enter the mixing chamber.

[0022] In some instances, the fumigation equipment includes a vaporization coil having a first end in fluid communication with the outlet of the mixing chamber and a second end forming or in fluid communication with the outlet of the fumigation equipment.

[0023] In some instances, the fumigation equipment includes a third channel serving as a purge line, which is in fluid communication with the gas source and engages with a second channel upstream of the mixing chamber. The third channel has a valve that, when open, allows the airflow to pass through the third channel to the second channel and purge the chemicals within it. The chemical pump may be located downstream of the point where the third channel engages with the second channel, enabling the chemical pump to be purged.

[0024] In some instances, the controller, the gas regulator, the pump, and the gas flow meter are housed within a housing configured to provide an oxygen-reduced environment. A portion of the first channel extending through the housing may include a purge port for injecting gas from the gas source into the housing to expel oxygen from the housing. An oxygen sensor may be disposed within the housing, and the controller is configured to shut off the heater in response to the oxygen sensor detecting oxygen in the housing.

[0025] In some instances, the heater is positioned above the mixing chamber. The second channel may contain a corrosion-resistant material. At least a portion of the first channel extending from the heater to the mixing chamber may contain a heat-resistant material. The vaporization coil may be both heat-resistant and corrosion-resistant. The portions of the second channel and the first channel extending from the regulator to the heater may be formed of a flexible material. The flexible material of the second channel may be coated with a corrosion-resistant material.

[0026] In some instances, the chemical fumigant is ethyl formate. In some instances, the non-flammable gas is an inert gas. The gas source may be located outside the fumigation equipment. The chemical source may be located outside the fumigation equipment.

[0027] In some instances, the fumigation equipment further includes a second temperature sensor for measuring the temperature of hot air in the first channel near the heater and sending information about the measured temperature to the controller, wherein the controller is configured to control the heater.

[0028] According to a second aspect of this disclosure, a fumigation apparatus is provided, the fumigation apparatus comprising: a mixing chamber including a first inlet, a second inlet, and a mixing chamber outlet, the first inlet for receiving a hot gas flow, the second inlet for receiving a chemical fumigant flow, and the mixing chamber outlet for discharging a mixture of hot gas and chemical fumigant; a gas regulator / pump / compressor for guiding a non-flammable gas flow from a non-flammable gas source along a first channel to the first inlet of the mixing chamber; and a heater for heating the gas flow in the first channel upstream of the mixing chamber to... The first inlet of the mixing chamber provides a hot gas flow; a chemical agent pump guides a chemical fumigant flow from a chemical fumigant source along a second channel to the second inlet of the mixing chamber; a fumigation equipment outlet is in fluid communication with the mixing chamber outlet for spraying the hot gas and chemical fumigant mixture; wherein the first inlet of the mixing chamber is located at a first end of the mixing chamber, and the second inlet of the mixing chamber is located at a second end of the mixing chamber opposite to the first end, such that the hot gas flow and the chemical agent flow enter the mixing chamber from opposite directions, thereby generating turbulence.

[0029] According to a third aspect of this disclosure, a method for fumigating using the fumigation equipment according to the first or second aspect is provided. The method comprises: allowing an inert gas to flow through a first channel to the heater, heating the inert gas and allowing the heated inert gas to enter the mixing chamber; pumping a liquid fumigant through a second channel into the mixing chamber; mixing the liquid fumigant and the heated inert gas in the mixing chamber to form a fumigant comprising a mixture of hot gas and vaporized fumigant, allowing the fumigant to flow out of the mixing chamber, and directing the fumigant from the fumigant equipment outlet to the area to be fumigated.

[0030] In some instances, the inert gas is selected from the group consisting of nitrogen, helium, and carbon dioxide. In some instances, the liquid fumigant is ethyl formate. Attached Figure Description

[0031] To facilitate understanding of this disclosure, embodiments will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of a fumigation apparatus according to an example of this disclosure; Figure 2 yes Figure 1 A perspective view of the fumigation equipment, in which the shell has been partially removed to allow the internal components to be seen; Figure 3 yes Figure 2 A side view of the fumigation equipment, showing the heater and mixing chamber; Figure 4 This is a schematic diagram of the components of a fumigation device according to an example of this disclosure; Figure 5 This is a flowchart illustrating a method for controlling the output temperature via a controller of a fumigation device, according to an example of this disclosure; Figure 6 This is a further flowchart illustrating, according to an example of the present disclosure, a method for controlling the output temperature via a controller of a fumigation device; Figure 7 This is a schematic diagram illustrating the operation of a controller controlling the output temperature of fumigant, based on an example of this disclosure; and Figure 8 This is a schematic diagram illustrating a control loop for controlling a heater, based on an example of this disclosure. Detailed Implementation

[0032] First refer to Figures 1 to 4 An example of fumigation equipment 100 is shown, which is used to vaporize a chemical fumigant, typically a liquid chemical agent, for application as a fumigant. A fumigant is a gaseous substance used to kill insects, nematodes, and other animals or plants that damage stored food or seeds. A chemical fumigant is a chemical agent that can be vaporized to form a fumigant.

[0033] Fumigation equipment 100 is particularly suitable for vaporizing chemicals with properties such as flammability, which are otherwise unsuitable or undesirable for use as fumigants. However, vaporization equipment 100 can be used to vaporize any chemical desired for use as a fumigant, including but not limited to ethyl formate, methyl bromo, 1,3-dichloropropene, chloropicrin, and propylene oxide. Fumigation equipment vaporizes chemicals by mixing a hot gas stream with a liquid chemical stream. Because some chemicals, such as ethyl formate, are highly flammable, the equipment uses a non-flammable gas to heat the chemical. The non-flammable gas can be, for example, an inert gas, such as, but not limited to, nitrogen, helium, or carbon dioxide.

[0034] It is desirable that the temperature of the fumigant (which comprises a mixture of hot gas and vaporized chemical agent) remain at or above the boiling point of the chemical agent as it leaves the device. Otherwise, the chemical agent may condense prematurely, resulting in incomplete or ineffective fumigation. When the hot gas stream mixes with the chemical agent stream, the temperature of the mixture is partly determined by the temperature and flow rate of the hot gas stream. The flow rate of the hot gas stream is particularly important because the higher the gas flow rate, the higher the temperature of the fumigant ejected from the device. Therefore, a first aspect of this disclosure proposes measuring the temperature of the fumigant leaving the fumigation equipment and dynamically controlling the flow rate of the gas stream based on the measured temperature to maintain the fumigant stream leaving the equipment at a predetermined temperature or higher.

[0035] In some prior fumigation equipment designs, incomplete mixing and vaporization of the hot gas and chemical agent has been found, which may lead to suboptimal fumigation. Therefore, a second aspect of this disclosure proposes a mixing chamber in which a hot gas flow enters through an inlet at a first end of the mixing chamber, and a chemical agent flows through an inlet at a second end of the mixing chamber opposite to the first end. This promotes turbulence and more complete mixing and vaporization of the chemical agent as the hot gas and chemical agent flows into the mixing chamber in opposing directions.

[0036] In some instances, components of the fumigation equipment may be retained or otherwise housed within housing 102. Housing 102 may include a frame and a cover. Examples are shown in Figure 1 The housing 102 may contain a polymer case. The polymer case is expected to be portable, lightweight, and waterproof, pressure-resistant, and dustproof. For example, the case could be a pelican™ style case. The case can be formed from copolymer polypropylene using an open core and solid wall construction.

[0037] The fumigation equipment 100 can be portable. For example, the fumigation equipment 100 can be presented as a substantially compact and transportable unit. Portability allows the equipment 100 to be easily moved from one processing location to another by a single operator. The portability and compactness of the fumigation equipment 100 enable it to be used in small areas such as small grain silos as well as larger areas such as warehouses, buildings, and ship cabins.

[0038] refer to Figure 1 The fumigation equipment 100 may include a first inlet 1, a second inlet 2, and an outlet 3. The first inlet is used to receive a stream of non-flammable gas, the second inlet is used to receive a stream of liquid chemical agent, and the outlet is used to spray a fumigant comprising a mixture of hot gas and vaporized chemical agent. Figure 1In the example shown, a first inlet 1 for non-flammable gases is adjacent to a second inlet 2 for liquid chemicals. The fumigation equipment may also include a control panel 4, which may be in the form of a display and connected to a controller for controlling the operation of the fumigation equipment. For example, the control panel 4 may be used to start and stop the flow of chemicals and non-flammable gases into the equipment, and to display and / or set the temperature and flow rate. The enclosure may contain a hinged lid 5. The fumigation equipment may have a power inlet 101 for receiving electricity.

[0039] The first inlet 1 can be fluidly connected to an external non-flammable gas source 11, such as a cylinder or gas generator, using a flexible tube or hose. The second inlet 2 can be fluidly connected to an external chemical agent source 13, such as a container of liquid chemicals, using a flexible tube or hose.

[0040] refer to Figure 4 The fumigation equipment 100 includes a first channel 10 leading from a first inlet 1 of the equipment to a mixing chamber 60 and a second channel 20 leading from a second inlet 2 of the equipment to the mixing chamber 60. In use, the mixing chamber 60 is used to mix a heated non-flammable gas stream with a chemical fumigant liquid stream, and to output a fumigant containing a mixture of hot gas and vaporized chemical fumigant from a mixing chamber outlet 66.

[0041] The fumigation equipment includes a gas regulator 12 for guiding a flow of non-flammable gas along a first channel 10 from a non-flammable gas source 11 to a first inlet 62 of a mixing chamber 60. In some instances, a pump or compressor may be used instead of a gas regulator, but gas regulators are cheaper and easier to control by the equipment's controller 40. In most cases, even if a pump or compressor (internal or external) is present to direct gas flow through the first channel 10, a gas regulator is still present to better control the pressure and flow rate of the gas in the first channel. The gas regulator, pump, or compressor is controlled by the controller 40.

[0042] The apparatus 100 further includes a chemical agent pump 22 for guiding a chemical fumigant flow along a second channel 20 from a chemical fumigant source 13 to a second inlet 64 of a mixing chamber 64. The apparatus also includes a heater 50 for heating a non-flammable gas flow in the first channel 10 to provide a hot gas flow to a first inlet 62 of the mixing chamber 60.

[0043] As mentioned above, the mixing chamber 60 includes a first inlet 62 ('hot gas inlet'), a second inlet 64 ('chemical agent inlet'), and a mixing chamber outlet 66. The first inlet receives a hot gas stream, the second inlet receives a chemical fumigant stream, and the mixing chamber outlet outputs the hot gas and chemical fumigant mixture. The fumigation equipment outlet 3 is in fluid communication with the mixing chamber outlet 66 and is used to spray the hot gas and chemical fumigant mixture ("fumigant") from the equipment. The fumigation equipment outlet 3 thus directs the fumigant into the surrounding atmosphere. The outlet 3 may have an orifice of sufficient size to maintain sufficient pressure to force the chemical / gas mixture outward, toward and into the area to be treated, and to minimize chemical condensation.

[0044] An insulated delivery tube, such as a hose (not shown), may be connected to fumigation equipment outlet 3 to help guide the fumigant to the area to be fumigated. The delivery tube should be long enough to deliver the chemical / gas to the treatment area, but also short enough and of appropriate diameter to avoid any significant cooling and condensation of the vapor as it travels from outlet 3 to the treatment area.

[0045] In some instances, a vaporization coil 70 may be present between the outlet 66 of the mixing chamber 60 and the outlet 3 of the fumigation equipment. The vaporization coil is a hollow coil. The vaporization coil may have a first end in fluid communication with the outlet 66 of the mixing chamber and a second end in fluid communication or fluid communication with the outlet 3 of the fumigation equipment. The mixing chamber 60 may be relatively small, for example, the size of a cigarette box, such as 80 to 12 cubic centimeters. The vaporization coil may be relatively long, for example, between 2 meters and 6 meters in length. The diameter of the vaporization coil may, for example, be between 8 mm and 20 mm. In one instance, the vaporization coil is 3.5 m long and has a diameter of 12 mm. The vaporization coil 70 allows the chemical fumigant to be completely vaporized and mixed with the hot gas stream before being sprayed from the fumigation equipment. Because the vaporization coil 70 is coiled, it is relatively compact despite its length, which allows it to be fitted inside the housing of the fumigation equipment, such as… Figure 2 and 3 As best shown. For example, in one instance, although the length of the tube coil is 3.5 m, it can be assembled from start to finish in a space of 26 cm.

[0046] The device may include a temperature sensor 72 for measuring the temperature of the gas-chemical fumigant mixture exiting the fumigation device outlet 3. The temperature sensor 72 may be located at or near the outlet 3. The device includes a controller 40 for controlling a gas regulator, pump or compressor 12, and / or chemical pump based on the temperature measured by the temperature sensor 72, to maintain the hot gas-chemical fumigant mixture exiting the fumigation device outlet at a predetermined temperature or higher. The predetermined temperature may be equal to or higher than the boiling point of the chemical fumigant to be used. In the case of ethyl formate, the predetermined temperature is at least 54 degrees Celsius. In some instances, the predetermined temperature may be at least 5 degrees Celsius, at least 10 degrees Celsius, or at least 15 degrees Celsius higher than the boiling point of the chemical fumigant. This allows for some cooling as the mixture of hot gas and vaporized chemical agent exits the fumigation device and comes into contact with ambient air. Otherwise, such contact with ambient air could cause the fumigant to condense upon exiting the device, especially in winter. In some instances, the predetermined temperature is 60 degrees Celsius or higher, in some instances it is 65 degrees Celsius or lower, and in others it is 70 degrees Celsius or higher.

[0047] The controller 40 may be an electronic device, such as a processor, microprocessor, programmable logic controller, field-programmable gate array, application-specific integrated circuit, etc. The controller may include a processor and a machine-readable storage medium, such as read-only memory, random access memory, or solid-state memory, which stores instructions executed by the processor to perform the control methods described herein.

[0048] The controller can be configured to receive the temperature of the output fumigant from the temperature sensor 72 and automatically control the gas regulator, pump, or compressor 12 to dynamically adjust the gas flow rate in the first channel 10 to achieve the desired output temperature. The desired output temperature can be referred to as the predetermined output temperature. As mentioned above, the predetermined output temperature can be equal to or higher than the boiling point of the chemical fumigant, ensuring that the chemical fumigant remains largely vaporized and does not condense immediately upon leaving the equipment.

[0049] In some instances, the fumigation equipment may further include a gas flow meter 19 for measuring the flow rate of the gas in the first channel 10, and the controller 40 may be configured to control the gas regulator, pump or compressor 12 and / or chemical pump 22 based at least in part on the flow rate measured by the gas flow meter 19. The gas flow meter may be located upstream of the heater 50 in the first channel 10, thus measuring the flow rate of cold or unheated gas before it is heated.

[0050] In some instances, controller 40 is configured to use a negative feedback loop to control gas regulator 12 to dynamically regulate the flow rate of gas passing through first channel 10, so as to maintain the temperature of the hot gas-chemical fumigant mixture at fumigation equipment outlet 3 at a predetermined temperature or higher. In some embodiments, controller 40 may control the flow rate using an air pump or gas compressor instead of a gas regulator.

[0051] Figure 5 This is a flowchart illustrating an example control method 500 using a controller with a negative feedback loop. At block 510, the controller 40 receives the temperature of the fumigant exiting the equipment outlet 3 from the temperature sensor 72. At block 520, the controller determines whether the measured temperature is too low or too high compared to a desired target temperature ('predetermined temperature'). If the measured temperature is too low, at block 530, the controller 40 increases the gas flow rate in the first channel 10. If the measured temperature is too high, at block 540, the controller decreases the gas flow rate in the first channel 10.

[0052] The flow rate of hot gas has a significant impact on the temperature of the fumigant output from the equipment, as the faster the flow, the more heat is transferred to the outlet. If the hot gas flow rate is too slow, the outlet temperature will drop below the predetermined temperature, and the chemical fumigant will not fully vaporize, or may condense within the equipment or upon contact with outside air, resulting in ineffective fumigation. Due to its high latent heat of vaporization, the gas passing through ethyl formate tends to cool rapidly, and in some cases, may even freeze if the gas temperature or flow rate is too low. On the other hand, if the flow rate is too high, this wastes gas (since inert gases are not free, there is a cost), may cause overheating, thereby damaging the equipment, and may even cause the concentration of the chemical fumigant to drop below the effective fumigation level. Therefore, the controller is configured to automatically control the gas flow rate and dynamically adjust the equipment as needed to achieve the desired flow rate.

[0053] In other instances, the controller may adjust the heater temperature and / or the pumping rate of the chemical agent, and / or instead adjust the airflow rate. However, typically, the pumping rate of the chemical agent will be set according to the fumigation requirements. Generally, fumigation will need to be completed within a set time and requires a set amount of chemical fumigant (e.g., ethyl formate). The specific volume of fumigant chemical required for fumigation can be calculated based on the type of fumigant and the volume of the space to be fumigated. Increasing the volume of fumigant may exceed toxicity limits and is expensive, as fumigants are more expensive than inert gases. Decreasing the fumigant rate will increase fumigation time, which is undesirable, as fumigation typically needs to be completed within a set time period for commercial purposes. Similarly, the heater is typically operated at its highest temperature to maximize the flow rate available for vaporization and reduce the time required to vaporize the reagent and deliver the fumigant. However, raising the heater temperature too high can damage equipment components. For these reasons, in some embodiments, it is advantageous to control the fumigant output temperature by adjusting the gas flow rate rather than the heater temperature or the chemical agent pumping rate.

[0054] Therefore, in some instances, the controller 40 can control the chemical agent pump 22 and / or heater regardless of the temperature measured by the temperature sensor 72 and the flow rate of the gas stream measured by the gas flow meter 19. Thus, in some embodiments, the rate of the chemical agent pump 22 may be independent of the temperature of the output fumigant and the flow rate of the gas in the first channel 10.

[0055] The controller 40 can change the flow rate of gas passing through the first channel by adjusting the pressure of the main gas regulator 12. Increasing the pressure increases the flow rate, while decreasing the pressure decreases the flow rate. The flow rate at a given pressure will depend on various factors, including the external environment in which the fumigant is injected, such as the back pressure generated by the external environment depending on the sealing of the container or area being fumigated, whether there are leaks in the container, temperature, and other conditions. In addition to varying by location, the flow rate achieved at a given pressure may differ during the fumigation process because the degree of back pressure changes as the fumigated area fills with fumigant and if the container exhaust is blown out during fumigation or other events. Therefore, the required pressure will depend on environmental conditions. Therefore, simply using the same pressure for all fumigations, or allowing the user to set the pressure and maintain a fixed pressure throughout the fumigation process, may not be effective. Therefore, the controller can employ a dual control loop, where the outer loop targets the desired output temperature of the fumigant, and the inner loop targets the flow rate that will achieve the desired output temperature. In this way, the device can take into account the differences between different fumigation environments and the dynamic changes in conditions.

[0056] Figure 6This is a flowchart of a control method 600 implemented by controller 40 according to an example employing a dual control loop. At block 610, controller 40 receives the temperature of the fumigant leaving equipment outlet 3 from temperature sensor 72. At block 620, the controller determines whether the measured temperature is too low or too high compared to a desired target temperature ('predetermined temperature'). If the measured temperature is too low, then at block 630, controller 40 determines a target flow rate or flow change that will provide the desired target temperature for the output fumigant. At block 640, the controller determines control parameters for adjusting a gas regulator, pump, or compressor, which will deliver the target flow rate or flow change determined at block 630. At block 650, the controller controls the gas regulator, pump, or compressor based on the adjustment of the control parameters determined in block 640. Therefore, it will be understood that in Figure 6 In the middle, boxes 610 to 630 serve as external control loops, while boxes 640 to 650 serve as internal control loops.

[0057] Controller 40 may be a PID controller. In some instances, the controller may use the desired output temperature of the fumigant as the setpoint and the measured output temperature as the process value. The controlled variable may be the regulator's pressure. In some instances, the first control loop may target the output temperature and output the desired flow rate as the setpoint for the second control loop, which may measure the flow rate as the process variable and control the regulator's pressure as the control variable.

[0058] Figure 7 An example configuration of a PID controller 700 according to an embodiment of this disclosure is shown. The controller uses a target temperature 710 of the fumigant as a setpoint. A comparator 720 compares the target temperature with the actual temperature 770 at outlet 3 as measured by temperature sensor 72. The comparator 720 outputs the result of this comparison to a step function F(x) 730, which maps the comparator output (temperature difference) to a target flow rate. The step function F(x) 730 outputs the target flow rate to a second comparator 740, which compares the target flow rate with the actual flow rate of gas in the first channel 10, as measured by flow meter 19. The second comparator 740 takes the difference between the target flow rate and the measured flow rate as input and outputs to a PID module 750. The PID module 750 determines the control parameters of the regulating gas regulator 760 to meet the target flow rate and controls the gas regulator accordingly. Through the fluid dynamics of the fumigation equipment, conceptually represented by F(x), this will ultimately lead to the achievement of the target output temperature. In this way, the controller dynamically adjusts the flow rate of the hot gas stream to maintain the temperature of the fumigant leaving the equipment at a desired level.

[0059] Gas source 11 may be an inert gas source. In some instances, the gas is one or more of nitrogen, carbon dioxide, or helium. The gas source may be housed in a container or tank suitable for storing compressed gas, such as a cylinder, the volume of which provides a sufficient amount of gas for at least one treatment application of the chemical agent as a fumigant. In other instances, gas source 11 may be a gas generator capable of producing a sufficient amount of inert gas by extracting inert gas from the atmosphere as needed. Non-limiting examples are pressure swing adsorption (PSA) or membrane separation (MS) nitrogen generators. In one embodiment, the gas source is a nitrogen generator capable of producing high-quality (>99%) nitrogen. The nitrogen generator provides dry, filtered, and heated air through a set of specially designed filter membranes. These membranes separate the nitrogen from CO2 and O2 exhaust gases and deliver the nitrogen to a delivery tube or other suitable conduit for delivery to the inlet of regulator 12.

[0060] The second inlet 62 of the mixing chamber may include a nozzle for atomizing the liquid chemical before or during its entry into the mixing chamber. The nozzle may, for example, be flush with the wall of the mixing chamber or may extend a short distance into the mixing chamber. By atomizing the liquid chemical, the nozzle promotes faster vaporization of the chemical upon contact with the hot gas flow in the mixing chamber. In some instances, the nozzle is a hydraulic atomizing nozzle. A hydraulic atomizing nozzle is a nozzle that receives a liquid flow and atomizes the liquid without mixing the liquid with a separate gas flow. Hydraulic atomizing nozzles can contrast with air or gas atomizing nozzles, which mix a liquid flow with a gas to achieve atomization. Using a hydraulic atomizing nozzle may slow down vaporization in the mixing chamber compared to using an air or gas atomizing nozzle, which may help prevent the equipment from overheating or heating up too quickly.

[0061] In some instances, such as Figure 4 As shown, the mixing chamber 60 is configured such that a first inlet 62 is located at a first end of the mixing chamber, and a second inlet 64 is located at a second end of the mixing chamber opposite to the first end, such that the hot gas flow 56 and the chemical agent flow 26 enter the mixing chamber from opposite directions. This helps to generate turbulence, which enhances the mixing of the chemical fumigant with the hot gas, promotes the vaporization of the chemical fumigant, and helps to ensure a more uniform distribution of the fumigant within the fumigant / gas mixture. In some embodiments, the mixing chamber outlet 66 is located on a sidewall that engages with the first and second ends of the mixing chamber, such that the hot gas and chemical fumigant mixture flows out of the mixing chamber through the outlet 66 in a direction substantially perpendicular to the direction in which the hot gas flow 56 and the chemical agent flow 64 enter the mixing chamber.

[0062] As mentioned above, the gas regulator 12 is in fluid communication with the gas source 11 via inlet 1. The gas regulator 12 controls the gas pressure in the section of the first channel 10 before the heater 50. The pressure of the gas regulator can be controlled by a controller to deliver the desired flow rate of gas in the first channel and / or the temperature of the fumigant output by the device, as described above. In some instances, the pressure can be 2-3 bar. In some instances, the flow rate of gas in the first channel, as measured by flow meter 19, can be 300 liters / minute to 400 liters / minute. In some embodiments, flow rates far exceeding this may pose a risk of overheating the device and / or damaging internal components.

[0063] Gas regulator 12 may be in fluid communication with heater 50. Gas regulator 12 may guide airflow from gas regulator 12 to heater 50 along first channel 10. Heater 50 may be an inline air heater in which gas enters through heater inlet 52 at a first end and exits through heater outlet 54 at a second end. Heater 50 may be designed for large gas flows and rapid heating of gas introduced into heater 50. Heater 50 may be able to heat gas introduced into heater 50 to a considerably high temperature while substantially maintaining the ambient temperature outside heater 50. Heater 50 may be powered by a power source (not shown), such as a single-phase power supply.

[0064] The fumigation equipment may include a second temperature sensor 56 for measuring the temperature of the hot air in the first channel 10 near the heater 50 and sending information about the measured temperature to a controller 40. The controller 40 may dynamically adjust the temperature of the heater 50 using a PID loop targeted to a specified temperature. An example configuration of the heater's PID control loop 800 is shown in [illustration]. Figure 8 The desired heater temperature 810 is used as the setpoint input to comparator 820. The comparator compares the desired temperature 810 with the actual temperature 850 measured by the second temperature sensor 56. Comparator 820 outputs the difference to PID module 830, which determines appropriate control parameters (such as input current or voltage) for adjusting heater 840 and controls heater 840 accordingly to achieve the desired heater temperature. As mentioned above, the desired heater temperature can be fixed throughout the process and set at a level that maximizes throughput without exceeding an upper limit that could damage components of the fumigation equipment.

[0065] Controller 40 controls both the on / off function of heater 20 and manages the temperature. In some instances, heater 20 is programmed to heat to temperatures from approximately 180°C to 500°C. In some instances, it is from approximately 240°C to approximately 320°C or up to approximately 500°C. The higher the heater temperature, the higher the gas flow rate, while still heating the gas to a sufficient temperature. Throughout the fumigation process, the heater temperature can be maintained at a constant level. In many cases, the equipment can be operated with the heater at or near its maximum temperature to maximize flow rate and reduce the time required for chemical vaporization and fumigant application. The heater temperature should be selected below levels that would damage internal components of the equipment, such as pipes or tubes forming the first passage between the heater and the mixing chamber. Therefore, in some instances, the temperature of the gas leaving the heater can be maintained at 320°C or lower.

[0066] The higher the boiling point of a chemical agent, the more energy is required to vaporize it. Ethyl formate has the highest boiling point among the most commonly used commercially available chemicals used in fumigation. Therefore, device 100 can be used to vaporize other chemicals with lower boiling points (such as, but not limited to, methyl bromide and propylene oxide). Device 100 can be used to vaporize various chemicals (including flammable and non-flammable chemicals) by appropriately adjusting and controlling the temperature of the heater 50 in use.

[0067] The gas enters the heater 50 at or near the first end 52, can be heated to a desired temperature inside the heater 50, and exits from the opposite end through the heater outlet 54. Due to cooling as the gas passes through the first channel 10 from the heater outlet 54 to the mixing chamber 60 inlet 62, and due to the latent heat required to vaporize the liquid chemicals in the mixing chamber 60 and the vaporization coil 70, the temperature of the heater 50 may be significantly higher than the temperature of the fumigant leaving the fumigation equipment. Therefore, the temperature of the hot gas and chemical fumigant stream exiting the mixing chamber outlet 66 and the fumigation equipment outlet 3 may be lower than the temperature of the heater 50. In some examples, the heater can heat the gas to 300-400°C, and the temperature of the mixture of hot gas and vaporized chemicals exiting the fumigation equipment outlet can be 54-70°C.

[0068] The chemical pump 22 can be positioned in fluid communication with the chemical source 13. The chemical source 13 can be external to and separate from the device 100, allowing the device 100 to extract, direct, and utilize chemicals from any source or container of any size, thus providing a substantially unrestricted source of chemicals for the device 100. This offers a significant advantage over prior art vaporization devices, where the volume of the chemical and the application range of the vaporization device are limited by the volume of a container, tank, or other such chamber that forms part of the device itself. Separating the chemical source from the device 100 also provides a safety advantage, resulting in minimal chemical residue in the device 100 after use, thereby mitigating the risks of toxicity and / or flammability.

[0069] In some instances, liquid chemicals can be pumped at a rate of 15-17 liters per hour. In others, it is approximately 15.8 liters per hour. In some instances, the rate can be set such that delivery of the fumigant to the area to be fumigated can be completed within 10-15 minutes. In some instances, the pumping rate of the chemical pump can be set such that 3 liters of liquid chemicals can be vaporized and delivered as fumigant within 10-15 minutes (approximately 14 minutes in some instances). The ratio of hot gas to vaporized chemicals in the fumigant output from the mixing chamber and fumigation equipment outlet will depend on the corresponding flow rates of the gas and liquid chemicals. As mentioned above, the gas flow rate is primarily used to control the output temperature and maintain it above a predetermined temperature. However, the concentration of fumigant in the output mixture should not exceed the safe level for human operation, and in the case of flammable chemicals, it should be kept below the lower explosive limit (LEL). The lower explosive limit of ethyl formate is approximately 2.8% of the volume of vaporized ethyl formate: the volume of a non-flammable gas (e.g., nitrogen), or 92 g / m³. 3 Ethyl formate. In some instances, it has been found that for every 3 liters of liquid ethyl formate pumped into the mixing chamber, 4,500-6,000 liters of non-flammable gas (as measured by a flow meter) are fed into the mixing chamber.

[0070] Some known fumigation devices require the operator to measure a fixed amount of chemical agent and introduce it into the device's container before each use. This necessitates handling the chemical agent and increases the risk of exposure to potentially toxic substances. The device 100 of the present invention reduces this risk because the operator does not need to measure and introduce the fixed amount of chemical agent. These known fumigation devices typically heat the chemical agent in the container. Introducing the chemical agent into the container will cause the reagent to vaporize upon contact with the heated elements within the container if the container is not allowed to cool sufficiently between chemical applications. Therefore, once the device has exhausted its fixed amount of chemical agent, it must be stopped and cooled before it can be refilled. The device 100 of the present invention avoids the need for a cooling period between the respective applications of chemical agent, thereby improving operational efficiency.

[0071] like Figure 2 As shown, heater 50 can be positioned above mixing chamber 60 to prevent any condensed chemicals from dripping from mixing chamber 60 into heater 50, which could cause a fire due to the flammable nature of some chemicals.

[0072] The first channel 10 may include one or more flexible material tubes. The first channel may further include one or more heat-resistant material tubes, such as metal tubes, adjacent to the heater 50 and leading from the heater 54 outlet to the first inlet of the mixing chamber 62. The second channel may include one or more flexible material tubes connecting the inlet 2 to the chemical pump 22 and the second inlet 64 of the mixing chamber. The second channel may contain or be coated with a corrosion-resistant material. For example, a material capable of delivering chemicals such as organic solvents without significant degradation, such as silicone, polyethylene, fluorinated ethylene propylene, or Teflon. The mixing chamber 60 may be formed of heat-resistant and corrosion-resistant materials, such as, but not limited to, stainless steel.

[0073] The fumigation equipment may have a third channel 30 serving as a purge line. The third channel 30 is in fluid communication with the gas source 11 and connects to a second channel 20 upstream of the mixing chamber 60. For example... Figure 4 As shown, the third channel 30 may have a valve 34, such as a solenoid valve, which, when open, allows airflow through the third channel 30 to reach the second channel 20, and thus purges the chemicals in the second channel 20. This helps maintain the lifespan of the fumigation equipment, as prolonged exposure, even when the second channel is formed of or coated with a corrosion-resistant material, can lead to deterioration and failure, especially if the channel is not cleaned and chemical residues remain in the second channel. Purges can also be used when the fumigation equipment will subsequently be used with different fumigants to prevent undesirable chemical reactions from occurring in the equipment.

[0074] The third channel 30 can be connected to the first channel 10 via a purge regulator 32. The purge regulator and / or purge valve 34 can be used to prevent backflow of chemicals into the first channel. In other embodiments, a separate one-way valve can be provided for this purpose. In the illustrated embodiment, the purge valve 34 is a two-way valve, in a first state connecting the purge regulator 32 and / or the first channel 10 to a second channel downstream of the purge valve 34, and in a second state connecting the chemical source and / or the second channel upstream of the purge valve 34 to a second channel downstream of the purge valve, the second channel leading to the second inlet 64 of the mixing chamber.

[0075] In some instances, such as Figure 4 As shown, the chemical pump 22 is positioned downstream of the point where the third channel 30 engages with the second channel 20 (i.e., downstream of the purge valve 34), allowing the chemical pump to be purged. This helps prevent pump degradation, which, surprisingly, occurs even in so-called corrosion-resistant pumps due to the corrosive nature of some chemical fumigants.

[0076] like Figure 4 As shown, the controller 40, gas regulator 12, pump 22, and gas flow meter 19 can be housed within a housing 102 configured to provide an oxygen-reduced environment 8. Other components, particularly electronic control components, can also be housed within the oxygen-reduced environment to reduce fire risk. A portion of the first channel 10 passing through the housing 102 may include a purge vent 16 for injecting gas from the gas source 11 into the housing to expel oxygen from it. This achieves an oxygen-reduced environment. An oxygen sensor 42 can be housed within the housing 102, and the controller 40 can be configured to shut off the heater 50 in response to the oxygen sensor detecting oxygen in the housing. Since the same gas source 11 is used to purge the housing and supply gas for heating through the heater, the oxygen sensor is able to detect the presence of any significant level of oxygen in the gas flowing into the heater. In response to detecting an oxygen level above a certain threshold, the controller 40 can automatically shut off the heater 50 to prevent or reduce fire risk. For a period of time after the heater is shut off, the controller 40 can continue to allow gas to flow through the channel 10 and into the heater 50 to cool the heater.

[0077] The fumigation equipment 100 described herein is suitable for surface application, including treating empty containers, to reduce the risk of pest infestation once materials such as bulk goods are introduced into the containers.

[0078] A method of fumigation using the fumigation apparatus 100 described above may include: flowing inert gas through a first channel 10 to a heater 50, heating the inert gas, and allowing the heated inert gas to enter a mixing chamber 60; pumping a liquid fumigant through a second channel 20 into the mixing chamber 60; mixing the liquid fumigant and the heated inert gas in the mixing chamber 60 to form a fumigant comprising a mixture of hot gas and vaporized fumigant in the mixing chamber 60, allowing the fumigant to flow out of the mixing chamber, and directing the fumigant from the fumigant apparatus outlet to the area to be fumigated. The combined mixture of gas and chemical agent exiting the outlet 3 may be applied as a film to the surface of the treated area, making the surface appear wet, but potentially evaporating rapidly from the treated surface. The surface temperature of the treated surface is increased by applying a hot gas flow, which facilitates the evaporation of the chemical agent.

[0079] In some instances, the inert gas may be one or more of nitrogen, helium, and carbon dioxide. In some instances, the liquid fumigant may be ethyl formate, propylene oxide, or methyl bromoethane. In some instances, the liquid fumigant is ethyl formate.

[0080] In use, the chemical source 13 and the gas source 11 can be locally placed in the device 100 and the area to be treated. The gas source 11 and the chemical source 13 are each connected to the device 100 via a first inlet 1 and a second inlet 2, respectively. If the gas source is a gas generator, such as a nitrogen generator, the gas source is activated until the desired gas purity is achieved. When the gas source is nitrogen, a nitrogen purity of >99%, more preferably about >99.4%, is preferred.

[0081] The chemical agent can be drawn into the device 100 by the action of pump 22 and guided towards the second inlet 64 of the mixing chamber 60 via the second channel 20. Gas can be guided from the gas source 11 towards the heater 50 via the first channel 10 by gas regulator 12. As described above, the heater 50 can be operated by controller 40, and the pressure of the gas regulator is controlled by the controller.

[0082] The gas is heated in heater 50, and the hot gas exits through heater outlet 54 and is directed toward the first inlet 62 of mixing chamber 60. The hot gas flow 56 then contacts a stream of liquid chemical particles entering mixing chamber 64 via a nozzle (not shown) at the second inlet 64. This vaporizes the liquid particles and mixes them with the vaporized chemical particles in mixing chamber 60 and vaporization coil 70, forming a vaporized chemical / gas mixture. This vaporized chemical / gas mixture is a fumigant suitable for application to the treatment area. The reagent / gas mixture is directed toward and exits outlet 3 and can be applied to the treatment area via an insulated delivery tube (not shown).

[0083] After fumigation of the treated area is completed, the equipment 100 can be shut off or powered off, thereby stopping the flow of gases and chemicals. The equipment 100 can be used for additional treatment applications at any subsequent time, if necessary. While vaporizing the chemicals and applying the fumigant may take anywhere from 10 to 40 minutes, depending on the size of the shipping container, warehouse, or area to be fumigated, fumigation typically takes several hours because the fumigant settles and remains on the applied surface for a certain period.

[0084] If an additional treatment application requires the use of a different chemical than that used in the previous application, the device 100 can be purged with gas or rinsed or cleaned with a suitable liquid to remove any residue of the first chemical, as described above. Since no chemical is stored in the device 100 during any application and the vaporization of the chemical is essentially complete, very little chemical residue remains in the device 100 after use, which significantly speeds up the cleaning process.

[0085] Those skilled in the art will understand that various changes and / or modifications can be made to the above embodiments without departing from the broad general scope of this disclosure. Therefore, the embodiments of the present invention should be considered illustrative rather than restrictive in all respects.

Claims

1. A fumigation apparatus, comprising: A mixing chamber, comprising a first inlet, a second inlet, and a mixing chamber outlet, wherein the first inlet is used to receive a hot gas flow, the second inlet is used to receive a chemical fumigant flow, and the mixing chamber outlet is used to output a mixed flow of hot gas and chemical fumigant. A gas regulator, pump, or compressor, said gas regulator, pump, or compressor being used to guide a flow of non-flammable gas from a non-flammable gas source along a first channel to the first inlet of the mixing chamber; A heater for heating the non-flammable gas flow in the first channel to provide a hot gas flow to the first inlet of the mixing chamber; A chemical agent pump is used to guide a flow of chemical fumigant from a chemical fumigant source along a second channel to the second inlet of the mixing chamber; The fumigation equipment outlet is in fluid communication with the mixing chamber outlet for spraying the mixture of hot air and chemical fumigant. Temperature sensor, the temperature sensor being used to measure the temperature of the gas-chemical fumigant mixture stream exiting the outlet of the fumigation equipment; as well as A controller for controlling the gas regulator, pump or compressor and / or the chemical agent pump based on the temperature measured by the temperature sensor, to maintain the hot gas and chemical fumigant stream exiting the fumigation equipment outlet at a predetermined temperature or higher.

2. The fumigation apparatus of claim 1, further comprising a gas flow meter for measuring the flow rate of the gas flow in the first channel, and wherein the controller is configured to control the gas regulator, pump or compressor and / or the chemical pump based at least in part on the flow rate measured by the gas flow meter.

3. The fumigation apparatus according to claim 1 or 2, wherein the controller uses a negative feedback loop to control the gas regulator, pump or compressor to dynamically adjust the flow rate of the gas passing through the first channel to maintain the output temperature of the hot gas and chemical fumigant mixture at the predetermined temperature or higher.

4. The fumigation equipment according to any one of the preceding claims, wherein the controller controls the gas regulator, pump, or compressor based on the temperature measured by the temperature sensor, and the chemical pump is independent of the temperature measured by the temperature sensor and / or the flow rate of the gas flow measured by the gas flow meter.

5. The fumigation apparatus according to any one of the preceding claims, wherein the predetermined temperature is at least 54 degrees Celsius.

6. The fumigation apparatus according to any one of the preceding claims, wherein the temperature of the hot gas and chemical fumigant stream exiting the outlet of the fumigation apparatus is lower than the temperature of the heater.

7. The fumigation apparatus according to any one of the preceding claims, wherein the controller is configured to control the gas regulator, pump, or compressor such that for every 3 liters of chemical fumigant pumped through the second channel by the chemical pump, 4,500 to 6,000 liters of gas flows through the first channel.

8. The fumigation apparatus according to any one of the preceding claims, wherein the second inlet of the mixing chamber comprises a nozzle for atomizing the liquid chemical agent entering the mixing chamber.

9. The fumigation equipment according to claim 8, wherein the nozzle is a hydraulic atomizing nozzle.

10. The fumigation apparatus according to any one of the preceding claims, wherein the first inlet of the mixing chamber is located at a first end of the mixing chamber, and the second inlet of the mixing chamber is located at a second end of the mixing chamber opposite to the first end, such that the hot gas flow and the chemical agent flow enter the mixing chamber from opposite directions, thereby generating turbulence.

11. The fumigation apparatus of claim 10, wherein the mixing chamber outlet is positioned on a sidewall engaging with the first end and the second end of the mixing chamber, such that the hot gas and chemical fumigant mixture flows through the outlet and exits the mixing chamber in a direction substantially perpendicular to the direction in which the hot gas and the chemical agent flow enter the mixing chamber.

12. The fumigation apparatus according to any one of the preceding claims, further comprising a vaporization coil having a first end in fluid communication with the outlet of the mixing chamber and a second end forming or in fluid communication with the outlet of the fumigation apparatus.

13. The fumigation apparatus according to any one of the preceding claims, having a third channel serving as a purge line, the third channel being in fluid communication with the gas source and engaging with the second channel upstream of the mixing chamber, the third channel having a valve that, when open, allows the airflow to pass through the third channel to reach the second channel and purge the chemicals in the second channel.

14. The fumigation apparatus of claim 13, wherein the chemical pump is located downstream of the point where the third channel joins the second channel, such that the chemical pump can be purged.

15. The fumigation apparatus according to any one of the preceding claims, wherein the controller, the gas regulator, the pump, and the gas flow meter are housed within a housing configured to provide an oxygen-reduced environment.

16. The fumigation apparatus of claim 15, wherein the portion of the first channel through the housing includes a purge exhaust port for injecting gas from the gas source into the housing to expel oxygen from the housing.

17. The fumigation apparatus of claim 15 or 16, wherein an oxygen sensor is disposed inside the housing, and wherein the controller is configured to shut off the heater in response to the oxygen sensor detecting oxygen in the housing.

18. The fumigation apparatus according to any one of the preceding claims, wherein the heater is positioned above the mixing chamber.

19. The fumigation apparatus according to any one of the preceding claims, wherein at least one of the following is present: the second channel comprises a corrosion-resistant material; at least a portion of the first channel extending from the heater to the mixing chamber comprises a heat-resistant material; the vaporization coil is heat-resistant and corrosion-resistant; and the portions of the second channel and the first channel extending from the regulator to the heater are formed of a flexible material; the flexible material of the second channel is coated with a corrosion-resistant material.

20. The fumigation equipment according to any one of the preceding claims, wherein the chemical fumigant is ethyl formate.

21. The fumigation apparatus according to any one of the preceding claims, wherein the non-flammable gas is an inert gas.

22. The fumigation apparatus according to any one of the preceding claims, wherein the gas source is located outside the fumigation apparatus.

23. The fumigation equipment according to any one of the preceding claims, wherein the chemical source is located outside the fumigation equipment.

24. The fumigation apparatus according to any one of the preceding claims, further comprising a second temperature sensor for measuring the temperature of hot air in the first channel near the heater and sending information about the measured temperature to the controller, wherein the controller is configured to control the heater.

25. A fumigation apparatus, comprising: A mixing chamber, comprising a first inlet, a second inlet, and a mixing chamber outlet, wherein the first inlet is used to receive a hot gas flow, the second inlet is used to receive a chemical fumigant flow, and the mixing chamber outlet is used to output a mixed flow of hot gas and chemical fumigant. A gas regulator / pump / compressor, the gas regulator / pump / compressor being used to guide a flow of non-flammable gas from a non-flammable gas source along a first channel to the first inlet of the mixing chamber; A heater for heating the airflow in the first channel upstream of the mixing chamber to provide a hot airflow to the first inlet of the mixing chamber; A chemical agent pump is used to guide a flow of chemical fumigant from a chemical fumigant source along a second channel to the second inlet of the mixing chamber; The fumigation equipment outlet is in fluid communication with the mixing chamber outlet for spraying the mixture of hot air and chemical fumigant. The first inlet of the mixing chamber is located at a first end of the mixing chamber, and the second inlet of the mixing chamber is located at a second end of the mixing chamber opposite to the first end, such that the hot gas flow and the chemical agent flow enter the mixing chamber from opposite directions, thereby generating turbulence.

26. A method for fumigating using the fumigation equipment according to any one of the preceding claims, wherein the method comprises: The inert gas is allowed to flow through the first channel to the heater, where it is heated and the heated inert gas is allowed to enter the mixing chamber. The liquid fumigant is pumped through the second channel into the mixing chamber; The liquid fumigant and the heated inert gas are mixed in the mixing chamber to form a fumigant that comprises a mixture of hot gas and vaporized fumigant, and allows the fumigant to flow out of the mixing chamber and directs the fumigant from the fumigant device outlet to the area to be fumigated.

27. The method of claim 26, wherein the inert gas is selected from the group consisting of nitrogen, helium and carbon dioxide.

28. The method according to claim 26 or 27, wherein the liquid fumigant is ethyl formate.

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