Typically, upon harvest, an agricultural commodity is placed in jute bags, boxes and/or stored in large enclosures, such as sheds, warehouses, or silos. Agricultural commodities after harvest are often infested with insects that can consume or damage substantial amounts of the commodity.
One approach to prevent these losses is to fumigate the commodity during storage and/or immediately prior to or after shipping.
Gas fumigants have been used for decades for disinfesting closed environments infested with or suspected to be infested with insect pests such as weevils, bugs, moths and cockroaches, either mature or in various larval stages or in the form of eggs. Such fumigation is particularly used for the disinfestation of agricultural bulk commodities such as, for example, non-food commodities, processed foods, raw commodities and fresh commodities.
Phosphine (PH3) has been a preferred gaseous fumigant for stored grain and similar particulate commodities because any residue of the fumigant will be lost or oxidized to a harmless phosphate when the grain or other commodity is processed to produce a food. Examples of the fumigation of grain with phosphine are found in the specifications of, for example, WO91/00017; U.S. Pat. Nos. 4,059,048; 4,200,657; 4,756,117; 4,812,291; 5,411,704 and 10,296,863. The entire teachings and disclosures of which are incorporated by reference herein.
The phosphine concentration pattern with the fumigation enclosure area can be influenced by, for example, temperature, air pressure and humidity. Phosphine gas concentration initially rises more or less steeply up to a maximum and from there drops asymptotically to zero at a rate which depends on phosphine losses due to leakage, decomposition or other causes. In extreme cases this may result in the phosphine concentration dropping so rapidly that complete killing of the pests, in particular their pre-adult stages, cannot be ensured. As a general rule it is preferred in phosphine fumigation to maintain lethal pesticidal gas concentrations as constantly as possible over a prolonged fumigation period. A skilled worker can refer to the teachings of U.S. Pat. No. 10,296,863 which discloses conventional calculations of air properties, boundary conditions, mass convective boundary conditions, optimization of fumigant dosage and treatment duration, how to account for gas flow within porous media, insect mortality in relation to gas levels, and various other models for estimating effective gas concentrations. The entire teachings and disclosures of U.S. Pat. No. 10,296,863 are incorporated by reference herein.
Accordingly, it would be desirable to be able to regulate the phosphine gas concentration pattern during fumigation and to maintain the desired lethal concentrations or pattern of concentrations over a prolonged period of fumigation by the controlled addition of fumigant gas.
Phosphine gas sensors serve to monitor the phosphine concentration in the enclosed fumigation area to ensure exposure sufficient to eradicate unwanted pests. Typically, phosphine gas is circulated through the stored commodity either by the natural convection currents that are present in the storage area or by active recirculation of air through the commodity using, for example, recirculation ducts. Examples can be found in, for example, U.S. Pat. Nos. 4,200,657 and 4,756,117. However, some commodities are very densely packed which creates an insulation effect whereby air/gas currents do not equally penetrate the interior of the community container. The air/gas circulation within the inner most areas of a densely packed commodity container can be significantly lower than the air/gas flow in the outer areas of a densely packed commodity container. Thus, the concentration of phosphine gas reaching the densely packed inner storage areas is often insufficient for the complete killing of pests. The industry has attempted to monitor the interior regions of a commodity container by means of gas sampling. However, this is problematic as negative pressures are created by the sampling pumps within the commodity container.
Some commercial sensors are designed to be inserted into the stream during commodity loading resulting in random placement of the sensor within the bin/truck/container. This is problematic as there is no way to retrieve the sensor to service or charge. It is also very problematic if the sensor is lost in the grain or commodity mass and is inadvertently introduced into the supply chain. A loose chip from a damaged or fragmented sensor could contaminate an entire batch of commodity resulting in substantial loss.
Thus, the need exists to monitor the supply of phosphine to all regions of the bulk-stored commodity in levels sufficient to eradicate unwanted pests. Moreover, phosphine gas is very corrosive and tends to quickly degrade or corrode electronics. Thus, the need exists for a phosphine sensor in which the electronic components are housed within an airtight sealed environment. A goal of the present invention is to provide a sensor that is able to accurately measure the gas concentration within the interior region of a bulk-stored commodity. A further goal of the present invention is to provide a sensor that is able to accurately measure the gas concentration within an ambient environment. A further goal of the present invention is to provide a sensor that is able to accurately measure the gas concentration within an ambient environment and within the interior region of a bulk-stored commodity. A further goal of the present invention is to provide a phosphine sensor device that is protected from the corrosive effects of the phosphine gas over an extended period. A further goal of the present invention is to provide a method a gaining access/space to place a sensor within the inner areas of a sealed commodity container. Upon further study of the specification and appended claims, further goals, objects and advantages of this invention will become apparent to those skilled in the art.
One embodiment of the present invention relates to a gas monitoring device comprising a perforated tip detachably connected to an enhanced gas tight housing unit having a rod end and a base end. The base end comprises a sensor, a sealed gap (155) between the bottom (111) of the sensor and a parts unit (139) containing a communication module (140) having a telemetry unit with an antenna, a processor (145), a circuit board (150) and an internal on/off switch. The rod end is narrower than the base end. Preferably, the elongated rod end of the housing is between 12 to 36 inches long. Preferably, the rod end is between 0.5 to 1 inch in diameter. Preferably, the perforated tip is between 0.5 and 2 inches long. Preferably, the base end is 4 to 10 inches wide and 2 to 6 inches tall. Preferably, the housing unit is made of a shock absorbing plastic.
A further embodiment of the present invention relates to a two piece commodity probe comprising a hollow outer sleeve with a tapered wall at a first end and a collar on a second end and a removable inner core with a spike on a first end and a collar on a second end. The inner core fits within the hollow outer sleeve and the spike extends beyond the tapered wall at the first end of said outer sleeve.
A further embodiment of the present invention relates to a method of monitoring the gas concentration within a fumigated commodity sample comprising inserting a two piece commodity probe into a commodity sample. The method advantageously does not require external gas sampling pumps. External gas sampling is often problematic and results in unreliable concentration data. The present method uses a two piece commodity probe comprising a hollow outer sleeve with a tapered wall at a first end and a collar on a second end and a removable inner core with a spike on a first end and a collar on a second end. The inner core fits within the hollow outer sleeve and the spike extends beyond the tapered wall at the first end of said outer sleeve. After placement in the commodity, the inner core is removed and a gas monitoring device is inserted into the hollow outer sleeve. The preferred gas monitoring device comprises a perforated tip connected to a gas tight housing unit having a rod end and a base end. The base end comprises a sensor and a sealed gap between the bottom of the sensor and the parts unit, a battery capable of wireless charging and an internal on/off switch. Connecting wire connects the sensor to the circuit board. The rod end is narrower than the base end.
Preferably, the gas monitoring method of the present invention measures phosphine gas concentration in parts per million. The data is collected and transmitted via a telemetry based communication unit at preset intervals and sent to cloud storage and/or cell phone.
Various features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
As used herein the term “perforations” or “perforated” refers to openings which allows airflow to reach the interior of the elongated hollow rod. They can be any size and shape (e.g., slots, holes, ovals, squares) which allow air into the interior of the elongated hollow rod to reach the sensor in the base unit. Preferably, the perforations are within the tip end of the elongated hollow rod which is about the top 50% of the elongated hollow rod.
The tip perforations can be any size and shape (e.g., slots, holes, ovals, squares) which allow air to reach the sensor. Several contemplated variations are depicted in
As used herein the term “Commodity container” refers to an enclosed environment containing stored commodities (e.g., vertical storage, tanks, flat storage (loose construction), farm bins, bunkers, tarped ground storages, railcars, barges, ship-holds, mills, warehouses, chambers, or silos). Commodity container can also include sub-containers stored with a larger enclosed environment such as, for example, cartons, wooden barrels, jute bags, woven bags, woven poly, supersack, bales, mesh bags, paper bags and/or plastic/poly bags.
Typical commodities requiring fumigation include, for example, non-food commodities, processed foods, raw commodities and fresh commodities.
Non-food Commodities include, for example, processed or unprocessed cotton, wool and other natural fibers or cloth, clothing; straw and hay; feathers, human hair, rubberized hair, vulcanized hair, mohair, leather products, animal hides and furs, tobacco, tires (for mosquito control), wood, cut trees, wood chips, wood products, bamboo products, paper, paper products, psyllium seed, psyllium seed husks, dried plants, flowers, seeds (such as grass seed, ornamental herbaceous plant seed and vegetable seed).
Processed food commodities include, for example, processed candy and sugar, cereal flours and bakery mixes, cereal foods (including cookies, crackers, macaroni, noodles, pasta, pretzels, snack foods and spaghetti), processed cereals (including milled fractions and packaged cereals), cheese and cheese byproducts, chocolate and chocolate products (such as assorted chocolate, chocolate liquor, cocoa, cocoa powder, dark chocolate coating and milk chocolate products), processed coffee, corn grits cured meat products, dried fish, dates, figs, dried eggs, egg yolk solids, dried milk, dried powdered milk, non-dairy creamers, non-fat dried milk, dried or dehydrated fruits (such as apples, dates, figs, peaches, pears, prunes, raisins, citrus and sultanas), processed herbs, spices, seasonings, condiments, malt, processed nuts (such as almonds, apricot kernels, brazil nuts, cashews, filberts, macadamia nuts, peanuts, pecans, pistachio nuts, walnuts and other processed nuts), processed oats (including oatmeal), rice (brewer's rice, grits, enriched and polished), soybean flour and milled fractions, processed tea, dried and dehydrated vegetables (such as beans, carrots, lentils, peas, potato flour, potato products and spinach), yeast (including primary yeast) wild rice and other processed foods.
Raw Commodities include, for example, almonds, animal feed & feed ingredients, barley, brazil nuts, cashews, cocoa beans, coffee beans, corn, cottonseed, dates, filberts, flower seeds, grass seeds, legume vegetables (dried), millet, oats, peanuts, pecans, pistachio nuts, popcorn, rice, rye, safflower seeds, sesame seeds, sorghum, soybeans, sunflower seeds, triticale, vegetable seeds, walnuts and/or wheat.
Fresh commodities include, for example, alfalfa, avocado, banana (including plantains), cabbage, citrus, citron, dill, eggplant, endive, grapefruit, kumquat, legume vegetables (succulent), lemon, lettuce, lime, mango, okra, orange, papaya, pepper, persimmon, pimento, salsify tops, sweet potato, tangelo, tangerine and/or tomato.
The parts unit contains a telemetry unit (32) which transmits collected data via wireless data transfer mechanisms (e.g., using radio RFID, ultrasonic, infrared systems, cellular telephone networks (e.g., GSM networks using SMS)). Preferably, the antenna is located toward the outer periphery of the parts unit in the region closest to the base unit housing.
In preferred embodiments the gas monitoring device stands between about 22 to 38″ tall. The tapered end of the elongated rod is perforated which allows for air/gas movement within the space. The elongated rod is detachably removable from the base. Thus, in certain environments it is desirable to place a removable filter medium within the rod so that it sits above, or adjacent the sensor contained within the base. The filter will protect the sensor from particulate matter and solid dust particles. The sensor operably connects to the circuit board located in parts unit of the base end (130). The base end is preferably 4″ to 10″ wide and 2″ to 6″ tall with a wall sloping inward towards the juncture with the rod end forming a cone shaped round base. In a preferred embodiment the base is adapted to support the device in a free-standing upright position such as depicted in
Generally, the base end is 4 to 10 inches wide and 2 to 6 inches tall. Preferably, the base end is 6 to 9 inches wide and 3 to 5 inches tall. Most preferably, the base end is 7 to 8.5 inches wide and 3.5 to 5 inches tall. It should be recognized that the base unit width is sufficient to support the housing unit in an upright position when placed on a support such as a floor. See, for example,
The base end of the device houses a data processer which may also contain internal memory. The data processor is configured to execute instructions in the memory and to read and write data to and from the memory. Preferably, the base unit contains enough memory to capture, for example, at least 30 days of data.
The base end also contains a parts unit (139) containing a communication module (140) having a telemetry unit with an antenna. The telemetry unit sends data preferably via non-Wi-Fi or Bluetooth means. Telemetry based communications such as SMS/GMS can work without the internet on mobile devices allowing push notifications in cases where the gas concentration thresholds dip above and/or below a preset level. The device is capable of worldwide communication. The telemetry unit includes an antenna operably connected to a radio transmitter configured to wirelessly transmit data. Preferably, the antenna is located in the outer periphery of the parts unit (the edge of the parts unit closest to the base unit housing). The telemetry device can send data to cloud storage where it can be processed into visually presentable data and graphic depictions of the fumigation process. The telemetry unit can be adapted to transmit gas (e.g., Phosphine) ppm data at selected preset intervals e.g., every 2, 4, 6, 8, 12, 24 hours. To save on battery life, the device may operate in a sleep mode in between selected intervals. The device may be a configured for a higher power usage awake mode and a lower power usage sleep mode thus extending battery life.
The base unit also houses a power supply e.g., battery (133) which may be operably coupled to the memory chip, the data processor, the radio transmitter, on-off switch and/or the sensor. Preferably, as the base unit (130) is sealed the power supply is a battery capable of wireless charging. Wireless charging, is also referred to as induction charging, and consist of two primary induction coils. One is housed in an external ‘charging base’, which is also commonly referred to as the ‘mat’. The external charging mat is responsible for generating an alternating current (AC) from within the mat. The other induction coil is located in the bottom half of the base device. Together, these two coils make up an electrical transformer.
When the base device is placed on a charging mat, it receives and harvests energy from a magnetic field, and uses it to power or recharge the battery.
The base unit may also optionally contain an LED power indicator, an ON/OFF indicator and a charge indicator. Moreover, as the unit is sealed the base unit also contains a magnetic on/off switch operably coupled to the power supply. The magnetic switch allows the sealed device to be turned on/off without an external connection into the sealed housing. A FOB associated with the unit may be used to activate the magnetic on/off switch. A cleaning tool may also be included with the FOB to allow cleaning of the perforations in the sensor tip.
Due to the corrosive nature of phosphine gas the electronic components housed within the base (in particular the antenna) must be protected in an airtight sealed environment. The sensor is sealed to the housing with rubber O-rings (156) and the base unit openings are sealed. Sealing of sensor with o-rings and providing an airtight seal to the base unit often does not provide sufficient long term protection from corrosion as it was discovered that the sensor itself is slightly permeable to the ambient air. The permeability of the sensor allows corrosive phosphine gas to reach the interior of the base unit resulting in early degradation of the of the base unit components with long term use. However, placement of additional sealant within the base unit itself needs careful consideration to protect against device failure. Sealant could transfer unexpected force to the data processor and telemetry unit, which could result in mechanical failure or be too insulating and cause thermal failure. Moreover, a suitable sealant must itself be non-corrosive to the interior components of the base unit. The above mentioned failure concerns were addressed, in part, by placing a gap filled with a suitable sealant between the bottom of the sensor and the parts unit (139) containing a communication module (140), a processor (145) and a circuit board (150). Most preferably, the gap sealant is a RTV silicone. The antenna is located on the periphery of the parts unit. The leads from the sensor to the circuit board run through the gap.
Preferably, the base unit is composed of two housings halves. The top half (151) and bottom half (152) are joined together with a chemical resistant adhesive/sealant. The adhesive/sealant used to join the top and bottom of the housing may be the same as or different from the adhesive/sealant used in the sealant gap between the bottom of the sensor and the circuit board. Preferably, the adhesive/sealant is a urethane, polysulfide, latex or silicone based sealant such as, for example, a silicone rubber. Preferably, the silicone adhesive/sealant has good flow-ability, low shrinkage, exhibits a high-temperature resistance, is acid and alkali resistant, and exhibits ageing resistance. The sealant is selected to be non-corrosive to the interior components of the base unit and with careful consideration of thermal insulating properties and aging resistance. Most preferably, the sealant is a RTV silicone (room-temperature-vulcanizing silicone). RTV silicones typically have a quick cure time and are commercially available as one-component products or mixed from two-components (a base and curative). RTV adhesive/sealant also allows for easier separation of the two base unit housing halves if repair or adjustments are required. In a preferred embodiment, sealant is also placed in a tongue groove that runs around the joining edge of the base unit halves. In certain embodiments the sealant may also applied to screws, which join the two housings halves of the base unit (top and bottom).
Additional protection is provided by application of a conformal coating to the base unit interior components. A conformal coating is a thin polymeric film, which conforms to the contours of the parts unit to protect the components against moisture, dust, chemicals, and temperature extremes. Conformal coatings are breathable. These coatings are not sealants. Conformal coatings also prevent current bleed between closely positioned components. Typically, conformal coatings are 10-250 μm thick.
Coatings can be applied in a number of ways, including brushing, spraying, dispensing and dip coating. Furthermore, a number of materials may be used as a conformal coating, such as acrylics, silicones, urethanes and parylene. Humiseal 1A33™ is a preferred commercially available conformal coating available from CHASE Corp. in Pittsburgh PA.
Telemetry based communications such as SMS/GMS can work without the internet on mobile devices allowing push notifications in cases where the gas concentration thresholds dip above and/or below a preset level. The device is capable of worldwide communication. The telemetry unit includes an antenna operably connected to a radio transmitter configured to wirelessly transmit data. The parts unit contains an antenna and a tuner circuit. To avoid overheating and distortion the antenna is preferably located on the outer periphery of the parts unit (towards the base unit housing).
Probe
Some embodiments are device is designed to be compatible with a 2-piece stainless probe unit used for the optional mode of inserting the device into a commodity.
End Use Software
The device includes software for fresh air calibration. Preferably, the unit zeros itself out when turned on. The device also includes calibration software which follow industry guidelines for gas concentration.
The base unit is adapted to transmit gas (e.g., Phosphine) ppm data at selected preset intervals e.g., every 2, 4, 6, 8, 12, 24 hours. The data, along with a time stamp, can be processed and accessed through a dashboard for viewing a graphical evaluation and/or reports of the fumigation concentration over time. Prior to fumigation, each job will be assigned a unique name (location and date) and each gas monitoring device is assigned a unique code (e.g., 4-digit unit ID). The unique location and unique device code associated with that fumigation are entered via the dashboard and named with a relevant name (e.g., warehouse number, silo number, container number, tarp number, etc.). During the fumigation, if a concentration received is below a preset ppm level, the software will send out an email and/or SMS notification to alert a predetermined group. Once the fumigation is over, the software will generate a post fumigation graph of phosphine concentrations in ppm vs. time in hours. The software allows access for guests invited to view the results of only that specific fumigation and the specific base units associated with it. Once the fumigation is over, the job will be finalized, and base units “released” from assignment.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the disclosure in any way whatsoever.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
Number | Date | Country | |
---|---|---|---|
63408599 | Sep 2022 | US |