Blocked orifice tube sensor for citrus juice extractor

A juice extractor includes a strainer tube mounted to receive juice and pulp of a fruit. An orifice tube reciprocates within the strainer tube and has an ejection port and is configured to generate pressure and separate juice and pulp, collect core, and discharge core out of the ejection port. A sensor is positioned adjacent the orifice tube and configured to sense material ejected from the ejection port.

FIELD OF THE INVENTION

The present invention relates to the processing of fruit and vegetables, and more particularly, this invention relates to a citrus juice extractor that includes a sensor configured to detect a blocked orifice tube and associated methods.

BACKGROUND OF THE INVENTION

Citrus juice extraction on a commercial scale is advantageously performed with a juice extractor. For example, an inline juice extractor manufactured by the assignee of the present invention includes opposing cups such as upper and lower cups that move relative to one another along a reciprocal path of travel. The sides of both the upper and lower cups typically include fingers that support a fruit so that it can be squeezed without bursting. The fingers of the upper cup interdigitate or intermesh with those of the lower cup. An orange, other citrus fruit or some types of vegetables can be fed, for example, to the bottom cup by a cam-operated feeding device. The upper and lower cups are then brought together so that the respective fingers of the cup intermesh and the fruit therebetween is accordingly squeezed.

Sharp, typically circular, cutters are positioned in the top and bottom cups. As the cups move relative to each other, the fruit is pressed against the cutters, which cut plugs from both the top and bottom portions of the fruit as the interdigitating fingers of the two cups mesh together. The cutting of the plug from the top portion of the fruit promotes separation of the peel from the internal portions of the fruit (i.e., juice and pulp). The plug cut from the lower portion of the fruit allows the internal portions of the fruit to be forced down into a strainer tube positioned just below the lower cup cutter. The strainer tube, in turn, is positioned within a manifold.

After the internal portions of the fruit have been squeezed into the strainer tube, an orifice tube moves upward into the strainer tube applying pressure to the internal portions of the fruit. This causes the juice and juice sacs, due to their small particle size, to flow through small holes of the strainer tube and into the juice manifold, thus separating out the juice and pulp.

Further details relating to the citrus juice extractor may be found in commonly assigned U.S. Pat. No. 5,970,861 to Suter et al.; U.S. Pat. No. 5,992,311 to Suter et al.; U.S. Pat. No. 7,156,016 to Schrader et al.; and U.S. Patent Publication No. 2009/0081338 to Mathews et al., and the entire contents of each reference which are incorporated herein by reference.

One of the design and engineering goals with this type of juice extractor has been to develop components used within the extraction process that will maximize yield and quality and increase productivity in extractor feed efficiency. One method for attaining these goals has been to provide automated systems that measure and control a juice extractor's performance when feeding fruit and extracting juice to ensure high product quality and overall yield. It is therefore desirable to sense or detect when poor fruit feeding or blockage occurs within the various juice extractor components that would negatively affect both juice yield and quality.

SUMMARY OF THE INVENTION

A juice extractor includes a strainer tube mounted to receive juice and pulp of a fruit. An orifice tube reciprocates within the strainer tube and has an ejection port and is configured to generate pressure and separate juice and pulp, collect core, and discharge core out of the ejection port. A sensor is positioned adjacent the orifice tube and configured to sense material ejected from the ejection port.

In an example, the sensor is configured to monitor the output of material ejected from the ejection port and determine when the orifice tube is blocked. In another example, opposing cups, such as upper and lower cups, are configured to support the exterior of a fruit. The drive mechanism is connected to the orifice tube and operative to reciprocate the orifice tube within the strainer tube. An extractor frame mounts the sensor in a position to be adjacent to the ejection port when the orifice tube is reciprocated into a position where core would be discharged.

In another example, the sensor includes a sensor body. A target plate is supported by the sensor body and configured to move a distance indicative of the density and force of material that is ejected from the ejection port and strikes the sensor. A proximity sensor is supported by the sensor body and configured to sense movement of the target plate. In another example, a processor is connected to the proximity sensor and receives and processes data regarding movement of the target plate and determines the extent of blockage in the orifice tube.

In another example, a magnet is connected to the sensor body and target plate and configured to bias the target plate from the sensor body. A first magnet is positioned adjacent the sensor body and a second magnet is positioned adjacent the target plate and repels each other to bias the target plate from the sensor body. A shaft extends through the sensor body and has a first end connected to the proximity sensor and a second end connected to the target plate through which movement of the target plate is transmitted to the proximity sensor. A target plate seal engages the sensor body and the target plate and provides a seal therebetween.

A method is also disclosed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially toFIGS. 1 and 2, a citrus juice apparatus10is now described. The apparatus10illustratively comprises a plurality of N citrus juice extractors15a-15n, each illustratively including a first juice output16a,16nand a second juice output19a,19neach having a flow of juice therethrough, and which feed into a common header20. In other embodiments, each juice extractor15a-15nmay include only one juice output, for example, or more than two outputs, for example. Each extractor15a-15nillustratively includes a plurality of pairs of extractor cups, and associated drive components17a-17noperatively connected to a controller18a-18nas will be appreciated by those skilled in the art. Further details of a representative juice extractor15aare disclosed in the above-identified U.S. Pat. No. 7,156,016 to Schrader et al.; U.S. Pat. No. 5,970,861 to Suter et al.; U.S. Pat. No. 5,992,311 to Suter et al.; U.S. Patent Publication No. 2009/0081338 to Mathews et al.

A juice finisher22is illustratively positioned at the output of the juice header20. Both the juice extractors15a-15nand the juice finisher22are representative of citrus juice processing devices that upon malfunction cause an undesired material release into the citrus juice output. Those of skill in the art will appreciate other similar citrus juice processing devices that may benefit from the undesired material detection devices and methods described herein.

In the illustrated example and as described in the incorporated by reference '338 published patent application, any of the juice extractors15a-15n, upon a malfunction, causes an undesired material release along with the flow of juice into a respective juice output. This malfunction typically occurs when the strainer tube86(FIG. 2) fails causing the undesired material release. A respective undesired material release (UDMR) detector21a-21nis illustratively coupled to a first juice output19a-19nfor detecting the undesired material release. A respective detector21a-21nis associated with each juice extractor15a-15nand coupled to its first juice output19a-19n. This permits identification of the failed extractor when a plurality of extractors are used, as will be appreciated by those skilled in the art. In addition, an undesired material release detector21a-21nmay also optionally send a signal to the respective controller18a-18nof the juice extractor15a-15nsuch as to stop the malfunctioning extractor.

In addition to or in place of the detectors21a-21nfor the extractors15a-15n, an undesired material release detector25may be positioned downstream from all of the extractors inline with the common header20as shown in the bottom portion ofFIG. 1. In this variation, the output from the undesired material release detector25may be coupled to the controllers18a-18nof all of the extractors15a-15nor to another control device for the group of extractors as will be appreciated by those skilled in the art.

Yet another undesired material release detector27is illustratively coupled downstream from the citrus juice finisher22. The output of the detector25is illustratively coupled to the controller23of the juice finisher22, and may shut down the finisher upon detecting an undesired release of the material. The undesired material release detector27for the juice finisher22may be used alone or in combination with any of the other detectors21a-21n,25as described above.

Referring toFIG. 2, a portion of a basic juice extractor unit50defining a juice extracting position of a juice extractor is illustrated. A moveable extractor cup80is mounted on a common cross bar, i.e., a cup support member, also referred to as the cup beam82in the illustrated embodiment. The cup beam82interconnects other moveable extractor cups, in one example, a total of five extractor cups, but that number can vary depending on design. The cup beam82reciprocates by a cam drive (not shown) contained in an upper portion of a juice extractor in this non-limiting embodiment. The fixed extractor cups54, e.g., lower extractor cups in the illustrated embodiment, are rigidly positioned relative to the extractor frame52and mounted on a cup bridge57. The moveable and fixed extractor cups80,54are formed as interdigitated extractor cups that have fingers84that intermesh together when the moveable extractor cup80engages fixed extractor cup54.

The moveable and fixed extractor cups80,54and their associated components, such as the prefinisher strainer tube86, the orifice tube56, and associated cup bridge57, form one juice extractor unit as shown inFIG. 1. A number of juice extractor units50can be ganged together in one juice extractor to increase production. The typical juice extractor machine includes five juice extractor units positioned at respective juice extracting positions. A fruit feeder (not shown) can work as a cam-operated device and includes feeding fingers, which deposit a single fruit in the fixed extractor cup54, such as by tossing the fruit into the extractor cup after receiving the fruit from the feeder table formed as a fruit guide assembly.

The cam-operated drive system in the upper part of the juice extractor forces the moveable extractor cup80into the fixed extractor cup54and as this occurs, the fruit F is pressed against the circular cutter90located at the top of the prefinishing strainer tube86. This cutter90cuts a plug in the bottom of the fruit to allow the internal portions of the fruit access to the strainer tube86. Another cutter92also cuts a plug in the top of the fruit to permit separation of the peel from the internal portions of the fruit, such as the pulp. As the fingers84of the extractor cups54,80interdigitate or mesh together, the inner portion of the fruit, such as the pulpy juice, is forced down into the strainer tube86contained within the juice manifold94. The peel surfaces do not contact the juice and any contamination by the extractives in the peel is minimized. The peel falls away outside the juice manifold94and can be collected by the peel screw conveyor, for example, (not shown) typically located under the extractor platform that mounts the various components and discharged into a hopper or other waste disposal container and conveyed through an exterior wall to a truck or trailer for further processing.

The continuing stroke of the moveable extractor cup80and the presence of a restrictor, for example, in the form of blockages, force the juice-bearing portion of the fruit through the perforated wall of the strainer tube86. This perforated wall is formed by small strainer tube holes98, which allow discharge of juice into the juice manifold94.

Back pressure is preferably applied into the orifice tube, for example, by a hydraulic device such as described in the incorporated by reference U.S. Pat. No. 5,992,311 or by limiting the size of the size of a restrictor. The orifice tube56reciprocates within the strainer tube86to compress any entrapped fruit particles and force any remaining juice through the perforated wall of the strainer tube. Core material, such as section membrane and seeds, are ejected typically from the lower portion of the orifice tube through an orifice tube ejection port97(FIG. 3) during reciprocating movement of that orifice tube. This cycle of juice extraction is then complete.

FIG. 3illustrates the orifice tube56that includes at its lower end the orifice tube ejection port97. The lower end of the orifice tube includes a cylindrically configured orifice tube support member102with a threaded portion104. The support member102is received into an orifice tube beam and associated drive mechanism103(FIG. 2). The orifice tube beam supports the various orifice tubes, which are driven by the drive mechanism. This orifice tube beam would reciprocate, reciprocating the orifice tubes56within the strainer tubes86. An adjustment nut106aids to secure the support member102to a mounting mechanism on the orifice tube beam and drive mechanism103(FIG. 2). It is possible to use more advanced designs such as disclosed in U.S. Pat. No. 5,992,311 that use hydraulic control of back pressure.

Additionally, the amount of juice yield and the type of juice can be varied by using different strainer tubes with different size holes98. Additionally, the back pressure into the orifice tube can be changed to vary the juice yield and type of juice such as disclosed in U.S. Pat. No. 5,992,311. Peel oil, such as liberated by the shredding action of the moveable and fixed cups' fingers, typically can be washed by water sprays around the extraction cups.

During the whole fruit extraction process described above with the illustrated citrus juice extractor, a whole fruit is separated into four major components in a near simultaneous fashion. These components includes: (1) pulpy juice; (2) peel; (3) frit (small pieces of peel); and (4) core material (membranes, seeds, peel plugs).

As the orifice tube56moves upward compressing the material within the strainer tube86, solid material such as the peel caps, seeds and membrane material is compressed and forced into a center bore hole of the orifice tube56. Back pressure is applied to this material by the compression force applied to the longitudinal hole, i.e., bore, that runs almost the entire length of the orifice tube, thus preventing the material from instantly being ejected out of the tube and causing the juice to be lost through this exit. During normal operation, the orifice tube56can hold as many as five to six extracted cores at a given time depending on the size and variety of the fruit being processed. The juice extractor is designed such that these cores are ejected in sequential order. When ejected, the core material is pushed out of the orifice tube56with varying degrees of force. This core material may also be ejected as a single component or as scattered debris with each of the components ejected disassociated with the other components from the same piece of fruit. In some instances, a piece of foreign material enters the juice extraction process and plugs the center bore hole of the orifice tube, preventing proper flow of the core material from being ejected through the ejection port97. The orifice tube is thus blocked, i.e., plugged, which causes a loss of yield and reduction in juice quality.

In those instances when the orifice tube56becomes blocked with material that prevents ejection of the core material that normally passes through the bore and out of the ejection port97, pressure within the strainer tube86can increase to a level that damages the strainer tube. In addition, if that high pressure is transferred hydraulically up into the fruit as it is being compressed, the peel can improperly rupture in the cup causing an explosion of the remaining contents of the orange within the cup and impair the capability of the various juicing components from collecting the juice and solids.

In accordance with a non-limiting example, the juice extractor includes a blocked orifice tube detector system that determines when an orifice tube is blocked and incapable of passing material through the orifice tube. This system in one example can identify which tube in a processing facility is blocked. Use of this system reduces both yield loss and degradation of juice quality when the bore of the orifice tube is plugged. A second benefit derived by the detection of ejected material from the orifice tube56is the ability to determine if a cup is not receiving fruit or if the rate of fruit entering the cup is such that the extractor loses efficiency in overall production.

This blocked orifice tube detector system provides instantaneous monitoring of the material that is ejected from the orifice tube through an ejection port97while the juice extractor is running. In one non-limiting example, the detector system includes five sensors one for each of the orifice tubes that typically are mounted for vertical movement in a single juice extractor. An example sensor110is shown inFIG. 3and positioned near the ejection port97of its respective orifice tube56.

A RPM sensor105(FIG. 2) is typically incorporated with a juice extractor machine. This RPM sensor is illustrated as a block module inFIG. 2and can be mounted in an appropriate position to sense orifice beam movement during extractor operation. It is typically an off-the-shelf sensor and formed as a proximity detector that measures the presence of the orifice beam. When the orifice beam moves in front of the sensor, the extractor has made a complete extraction cycle as 1 RPM. In a non-limiting example, the RPM sensor105is an 18 mm proximity device with extended range of up to 12 mm designed for food grade applications and operates similar to an IFM Effector model IGT205. Each RPM sensor105has a threaded connector to aid in its insertion and removal on the RPM sensor mounting frame. This connector cooperates with a molded cable that is typically a M12 three or four pin connector, depending on the manufacturer of the sensor. This cable is routed along a RPM sensor mounting frame and diverted outside the extractor where it is terminated to an I/O device monitored by the extractor control system.

Each sensor110(FIGS. 3-7) used to sense material ejected from the orifice tube is mounted via a mounting assembly (not shown) and supported typically by the extractor frame. A control system, such as a processing unit that can also operate the juice extractor, can receive data from each sensor110for processing. Each sensor110is illustrated inFIGS. 3-7and is designed to operate within the extremely harsh environment of a juice extractor. Each sensor can measure both large and small particles ejected out of the orifice tube56while being immune to the environment that applies both high vibration loading as well as high temperatures ranging from <50° F. to >160° F., including saturated humidity. This illustrated sensor110withstands harsh environments, but remains sensitive to measure when core material is ejected from the ejection port97by contacting the ejected material.

As illustrated, each sensor110is placed in front of the ejection port97on the orifice tube. Due to the variability of the size and mass of the material ejected from the ejection port97of the orifice tube56, which is often determined by the fruit type and size range, the gap distance from the impacted target plate area forming the end of the sensor to the ejection port97ranges from 0.25 inches to as much as 1.0 inches. Typically, this gap is set based on the season because of climate impact on fruit and based on which predominate fruit is being processed. An example gap distance for optimum performance on oranges ranging in the small to average size is from about 0.5 to 0.75 inches. Limes having less than a two-inch diameter would have an optimum gap distance from about 0.25 to 0.5 inches. Typically once a sensor110has been set for a given location on a line of extractors, the gap does not need to be changed during the season once fruit has begun to be processed on that extractor.

Each sensor110is designed to be struck by the material ejected from the ejection port97. Testing indicates that the contact pressure from this material on the sensor110can be as low as 15 grams and as high as 300 grams for a period less than 5-60 milliseconds in duration and the sensor remains operable. The sensor110can operate at a wide range of juice extractor speeds. The forces applied to the sensor110, as well as its duration, vary dramatically based on fruit size and type of fruit and yet under many different circumstances, the sensor is operable. The sensor110can be used in many different fruit processing stages on a juice extractor and on many different types of fruit typically processed in citrus extraction worldwide throughout the citrus industry.

The sensor110can be coupled to a high speed data collection control system, such as part of the processing unit or controllers18a-18nshown inFIG. 1. The data from a sensor110, both on an individual juice extractor basis and on a line basis of multiple juice extractors such as shown inFIG. 1, can be used to extrapolate when a failure of either a blocked orifice tube or lane blockage has occurred and provide detailed information to the serviceman as to the location where the problem has been detected.

During normal operation, that material forced through the center of the orifice tube is ejected on a first-in, first-out basis from the ejection port97of the orifice tube. This ejected material strikes the sensor110that is located directly in front of the ejection port as best shown inFIG. 3. The sensor110is fixed and mounted on a stationary frame assembly for the juice extractor. The sensor110does not move as compared with the orifice tube56, which as noted before, moves in a vertical up and down motion at a high rate of speed dependent on the RPM of the juice extractor machine. Typically, the cycle rate for this vertical orifice tube movement is between 100 and 120 times per minute. By nature of the design of the sensor and the corresponding controls monitoring the sensor, output speed does not impact the performance of the sensor.

Referring now toFIG. 4, a more detailed and exploded perspective view of the sensor110is illustrated. The sensor includes the following non-limiting components: target plate120; target plate seal122; target plate seal shield124; target plate mounting screw126; target plate repelling magnet128; sensor body130; sensor body repelling magnet132; sensor body shaft134; sensor body vent port136; sensor body shaft end screw138aand washer138b; proximity sensor140and a snap clip or clamp150that fits around the body130and is received into the grooves130alocated at the end of the sensor body130. This clamp150receives and secures a flexible “boot” or cover that is designed to extend over the body and make it more air and water tight and provide a better seal. This prevents liquid intrusion into the sensor. In some instances and depending on the operating environment to which the sensor is subjected, the vent port136may not be required, but typically the sensor110will include the vent port.

FIG. 5is a fragmentary plan and partial sectional view of the sensor andFIG. 6is a detailed sectional view of the sensor110taken along lines6-6inFIG. 5. The vent port136in the embodiment ofFIG. 5communicates with the internal cavity130aformed in one end of the sensor body that receives the two magnets128,132and also receives an end of the sensor body shaft134, which is received within a longitudinal bore130bextending from one end of the sensor body and into the internal cavity130a. The vent port136vents that cavity130asuch as by communicating with the internal cavity as inFIG. 5or with the longitudinal bore130bas shown inFIG. 6. The target plate120includes a hub member120athat is received within the end of the sensor body at the internal cavity. The target plate mounting screw126is secured into the end of the sensor body shaft134and the other sensor body shaft end screw138ais received in the other end of that shaft134. The components are secured together.

FIG. 6is a sectional view and also shows representative but non-limiting examples of dimensions that could be used to form the sensor110. The sensor body140could have a diameter “A” of about 1 inch in a non-limiting example. The height “B” of the sensor110from the end of the proximity sensor to the target plate seal shield124is about 4 inches and in a non-limiting example about 3.9 inches but can range depending on specific applications and design. The length “C” from the end of the body member130to the target plate seal shield is about 2.5 inches and the distance “D” between the rear of the target plate seal and target plate seal shield is about 0.5 inches. The diameter “E” of the target plate is about 3 inches in a non-limiting example.

FIG. 7is a complete perspective view of the sensor110showing various components. The two opposing magnets as the target plate repelling magnet128and the sensor body repelling magnet132advantageously keep the target plate120away from the sensor body130. In one example, the two magnets128,132are neodymium magnets and formed as high density flux, ring magnets. The repelling force imparted by these magnets is not impacted by the high “g” forces of vibration found in the juice extractor. These vibrational forces are created by the vertical forces applied by the juice extractor and the “ringing” non-linear forces developed from the platform surface that mounts the juice extractor. These non-unidirectional vibrations prohibit the use of typical methods associated with sensors of this type.

The sensor body shaft134can be formed as a titanium alloy shaft and configured to extend through the magnet128,132cores and allow for detection of low pressure spikes applied to the target plate seal shield124and transmitted through the target plate seal122to the target plate120when in contact with the core material. Stainless steel material typically has some amount of ferrous material in its composition. Because any ferrous material passing through the magnets128,132will be attracted to the magnets and thereby affect the free movement of the shaft134, field evaluation has shown that an optimum material used for the shaft134is titanium. Use of plastic for this shaft is unsuitable due to the flexibility of the material. Other non-ferrous materials such as copper is subject to severe oxidation due to the sensor environment.

This method of isolation for the shaft134allows for movement of the target plate seal shield124, the target plate seal122, and target plate120, which is attached to the sensor body shaft134, inducing it to move towards the rear of the sensor110in proportion to the movement of the target plate120. The sensor body shaft134is not affected by the flux of the magnets128,132. Thus, only minor frictional loss occurs from movement of the shaft134. At the opposite end of the shaft134, an end screw138ais received into the detection area140aof the proximity sensor140, which is typically a m12 food grade proximity sensor similar to an IFM effector MODEL IFM203. The time in which the sensor is located within the detection range of the proximity sensor varies depending on the density of the material striking the target plate120and the force with which it was ejected from the orifice tube56through the ejection port. While not critical, the time duration of detection must be sufficient to allow for any control system to monitor that a signal has been produced by the proximity sensor140. Typically, this is not less than 5 milliseconds. Through empirical testing it has been determined that the repelling magnets128,132are optimally formed as ring magnets as a N52 neodymium magnet and a N42 neodymium magnet that is 0.5 inches by 0.1875 thick and include a 0.219 inner diameter. A preferred pretreatment of coating the magnets with an epoxy sealant and/or plating is necessary to prevent degradation of the magnetic material.

The sensor110includes the flexible rubber seal122, which prevents particles from entering the sensor body allowing free movement of the body with minimum restriction to movement. Due to the abrasiveness of the core material striking the target plate120and thus dislodging the seal from the target, the protective target plate seal shield124sandwiches the seal122to the target plate120, preventing direct contact to the seal surface. This seal has been designed to be highly flexible allowing for minimum resistance to the movement of the target plate and its associated parts. This is primarily achieved by the selection of material, such as high strength silicon of about 30 durometer in a non-limiting example, and the use of a bellow style design as illustrated.

FIGS. 3-5and7show the vent port136, which is mounted near the contact point of the seal122to the sensor body130and communicates with the internal cavity130aand the longitudinal bore130b. Due to the extreme environmental variations and the sensitivity of the sensor110to applied forces, the internal areas of the sensor body are required to be vented to equalize pressure on both sides of the target plate120as the target is oscillating in its horizontal position when struck by material and then forced back by the repelling force of the magnets128,132. To prevent contamination of the sensor110from suctioning in unwanted solids or liquids within the surrounding area of the sensor, the vent port136is either connected at its end to a manifold open to the atmosphere in a clean area or connected to a high capacity filter used with each sensor. The end of the vent port includes a filter to connect to a hose such as a vacuum hose or other connector. Details of the construction of the vent port are explained above relative to the description ofFIG. 5. If used with venting, the filter is typically a sintered metal filter used which allows gas flow exchange while holding back water or juice from getting into the sensor body.

Testing has been conducted to determine how well the sensor operates. The sensor110has detected the ejected material from fruit that is less than 1.5 inches and greater than 4 inches. In addition, different types of citrus fruit have been processed, including lemons, limes, oranges and grapefruit under laboratory testing conditions at John Bean Technologies Corporation's research facility in Lakeland, Fla.

At the conclusion of initial testing, enhancements had been made to the sensor to provide sealing of the sensor body130. The target plate seal122had been added. After development of the seal122to fit between the sensor body130and the target plate120, testing was reviewed and after two months of testing, the target plate seal shield124was added. The target plate seal is fabricated using high strength silicone that is 30 durometer in one non-limiting example. Once the target plate seal122was modified to prevent contamination of the internal operation of the sensor body130, it was found that the internal cavity needed to be vented. This led to the introduction of the vent port136and additionally a vent port manifold or vent port filter. If used, the filter is typically a sintered metal filter used which allows gas flow exchange while holding back water or juice from getting into the sensor body.