Methods and apparatuses for digesting tissue

Embodiments of this disclosure relate to tissue digestion and, more particularly, to methods and apparatuses for varying the number, size, and/or location of one or more tissue compartments within a digestive fluid vessel. Some examples include partitions that may be selectively positioned within a vessel (and may be selectively removable from the vessel) to create one or more tissue compartments. The partitions may be positioned, repositioned and rearranged within the vessel to form one or more tissue compartments. The partitions may be solid or include apertures, and may be oriented in horizontally and/or vertically. Alternate embodiments include one or more selectively closeable apertures that permit digestive fluid to circulate along alternate pathways, which can permit tissue digestion with reduced digestive fluid levels. Still further embodiments include baskets that are selectively positionable within the tissue digester. The baskets may also include one or more selectively positionable and/or repositionable partitions.

FIELD

Embodiments of this invention relate to tissue digestion and, more particularly, to a method and apparatus for quickly and safely digesting animal tissue.

BACKGROUND

Many institutions generate organic waste that requires proper disposal. For example, veterinary offices frequently require disposal of dead, and possibly diseased, animal carcasses. For many years burial and incineration (cremation) were the primary manners in which such tissue was disposed. In recent years tissue digesters have been increasingly used as an alternative to burial or incineration for the orderly disposition of tissue. Alkaline hydrolysis, which exposes the tissue to a strong alkaline (or base) solution, is a process used in many tissue digesters. Most, if not all, of the tissue is digested (dissolved) in the tissue digesters, and the dissolved tissue is then considered safe to discharge into the environment. The mineral ash of bones and teeth typically remain at the end of the process (approximately only five percent of the original weight and volume of a carcass or body), but is sterile and easily crushed into a powder that may be used as a soil additive or presented to the family in an urn in much the same way as ash from a crematory. Since most tissue disposal systems are large and expensive, veterinary offices and others in need of disposing of smaller animal bodies, such as typical household pets, would have to use outside disposal services for disposing of dead animals such as hiring an animal crematory.

SUMMARY

Embodiments of the present invention provide improved low-temperature alkaline hydrolysis tissue digestion methods and apparatuses.

In accordance with one preferred embodiment of the present invention, a tissue digester with adjustable internal tissue compartments and adjustable alkaline digestive fluid levels that digests tissue (e.g., carcasses and/or cadavers) is disclosed.

In some embodiments, an apparatus comprising a housing containing a fluid vessel for holding digestive fluid; a wall positioned within the fluid vessel, the wall partially separating the fluid vessel into a pump intake plenum and a tissue compartment; the fluid vessel having a bottom area shared between the pump intake plenum and the tissue compartment, the bottom area permitting fluid communication between the pump intake plenum and the tissue compartment, and an upper opening permitting fluid communication between the pump intake plenum and the tissue compartment; and one or more substantially horizontal platforms positioned within the tissue compartment is disclosed.

In certain embodiments, the wall includes at least one intermediate opening permitting fluid communication between the pump intake plenum and the tissue compartment. In further embodiments, the apparatus also includes a baffle configured to selectively block one of the at least one intermediate opening.

In select embodiments, the disclosed apparatus further comprises a fluid pump operatively coupled to the housing and disposed in the pump intake plenum. In some embodiments, the fluid pump is arranged to circulate fluid between the pump intake plenum and the tissue compartment.

In further embodiments, the one or more substantially horizontal platforms are configured to permit vertical fluid flow within the tissue compartment. In some embodiments, the apparatus further includes one or more platform supports arranged to support each of the one or more substantially horizontal platforms within the tissue compartment.

In some embodiments, the disclosed apparatus includes one or more vertical separators positioned within the tissue compartment, the vertical separators dividing the tissue compartment into a plurality of sub-compartments.

In certain embodiments, the disclosed apparatus further comprises a heater operatively coupled to the housing, the heater including a heating element disposed in fluid vessel. In further embodiments, the housing further comprises a discharge port in fluid communication with the fluid vessel, the discharge port controlled by a drain valve, and an access panel providing access to the drain valve. In select embodiments, the disclosed apparatus also includes a control box operatively coupled to the housing.

In some embodiments, a method for digesting tissue comprising providing a tissue digester, the tissue digester including a fluid vessel; loading tissue onto a substantially horizontal platform within a tissue compartment within the fluid vessel; adding digestive fluid to the fluid vessel; engaging a fluid pump disposed in the fluid vessel; and digesting the tissue is disclosed.

In further embodiments of the method, the step of loading tissue onto a substantially horizontal platform includes the further steps of inserting an additional substantially horizontal platform into the tissue compartment, the tissue compartment partially separated by a wall from a pump intake plenum within the fluid vessel; and unblocking a selectively blockable opening in the wall.

In some embodiments of the method, the step of loading tissue onto a substantially horizontal platform includes the further steps of inserting an additional substantially horizontal platform into the tissue compartment, the tissue compartment partially separated by a wall from a pump intake plenum within the fluid vessel; blocking a selectively blockable opening in the wall; and loading tissue onto the additional substantially horizontal platform.

In certain embodiments of the method, the step of loading tissue onto a substantially horizontal platform includes the steps of: placing one or more vertical separators within the tissue compartment, thereby separating the tissue compartment into a plurality of sub-compartments; and loading tissue into one or more of the sub-compartments. In certain embodiments of the method, this step includes a further step of inserting an additional substantially horizontal platform into the tissue compartment, the one or more vertical separators registering with a vertical wall engagement location on at least one of the substantially horizontal platform and the additional substantially horizontal platform.

In further embodiments of the method, the step of digesting the tissue includes the step of maintaining the temperature of the digestive fluid at a predetermined temperature. In some embodiments, this step includes disposing a heating element in the fluid vessel.

In certain embodiments, the disclosed method includes the subsequent step of draining the digestive fluid from the fluid vessel through a discharge port in fluid communication with the fluid vessel.

This summary is provided to introduce a selection of the concepts that are described in further detail in the detailed description and drawings contained herein. This summary is not intended to identify any primary or essential features of the claimed subject matter. Some or all of the described features may be present in the corresponding independent or dependent claims, but should not be construed to be a limitation unless expressly recited in a particular claim. Each embodiment described herein is not intended to address every object described herein, and each embodiment does not necessarily include each feature described. Other forms, embodiments, objects, advantages, benefits, features, and aspects of the present invention will become apparent to one of skill in the art from the detailed description and drawings contained herein. The various apparatuses and methods described in this summary section, as well as elsewhere in this application, can be expressed as a large number of different combinations and sub-combinations. All such useful, novel, and inventive combinations and sub-combinations are contemplated herein, it being recognized that the explicit expression of each of these combinations is unnecessary.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to selected embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended; any alterations and further modifications of the described or illustrated embodiments, and any further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates. At least one embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features or some combinations of features may not be shown for the sake of clarity.

Any reference to “the invention” herein is a reference to an embodiment of a family of inventions, with no single embodiment including features that are necessarily included in all embodiments, unless otherwise stated. Further, although there may be references to “advantages” provided by some embodiments of the present invention, it is understood that other embodiments may not include those same advantages, or may include different advantages. Any advantages described herein are not to be construed as limiting to any of the claims.

Although specific quantities (spatial dimensions, temperatures, pressures, times, force, resistance, current, voltage, concentrations, wavelengths, frequencies, heat transfer coefficients, dimensionless parameters, etc.) may be used explicitly or implicitly herein, such specific quantities are presented as examples only and are approximate values unless otherwise indicated. Discussions pertaining to specific compositions of matter are presented as examples only and do not limit the applicability of other compositions of matter, especially other compositions of matter with similar properties, unless otherwise specifically indicated.

Depicted inFIGS. 1-10is a tissue digester100according to one embodiment of the present disclosure. Referring toFIGS. 1-4, tissue digester100includes a digesting housing140, a lid102(which covers the top of digesting housing140when in a closed position), fluid circulation member (for example, pump112), and a control box104. Digesting housing140includes one or more access panels142that may be removed to provide access to various components of tissue digester100. Tissue digester100further includes discharge port114for draining tissue and fluid from within tissue digester100and an optional heater157for heating the digestive fluid.

Referring now to the sectional views of tissue digester100depicted inFIGS. 5 and 6, fluid pump112is connected to pump motor110by pump drive shaft111. Pump drive shaft111extends through pump intake plenum144, which during operation is at least partially filled with fluid. Pump112, which may be a propeller (such as a ducted propeller), an impeller, or other type of pump as would be appreciated by one of ordinary skill in the art, circulates fluid within fluid vessel146in the directions depicted by fluid direction arrows113.

Within the fluid vessel146, wall148partially separates pump intake plenum144from tissue compartment150, leaving a bottom area146aof the fluid vessel146shared between the pump intake plenum144and tissue compartment150, and an upper opening156permitting fluid communication between the pump intake plenum144and tissue compartment150. In some embodiments, the wall148includes at least one intermediate opening152. Intermediate opening152may be selectively inhibited (e.g., blocked) by baffle154, such as by sliding baffle downward into an orientation that covers opening152. Fluid flows readily through opening152when it is not blocked by baffle154. When opening152is blocked by baffle154, fluid is inhibited from flowing through opening152. By selecting whether opening152is blocked or not blocked, the location(s) at which fluid enters the pump intake plenum144from tissue compartment150can be controlled. Opening152is sized to permit a flow of fluid from tissue compartment150to intake plenum144that is sufficient to avoid cavitation of pump112. In the illustrated embodiment, opening152is typically open (not blocked by baffle154) for low fluid level operation and typically blocked by baffle154for high fluid level operation.

Heater157, which includes heating elements158, is optionally included within fluid vessel146and used to heat the fluid during operation. As the fluid flows over heating elements158in direction113, heating elements158of heater157transfer heat to the flowing fluid. In some embodiments heater157is an electric heater, while in other embodiments heater is powered by steam or other heating means as would be appreciated by one of ordinary skill in the art.

Located within tissue compartment150are one or more tissue separators, also referred to as partitions. The partitions include substantially horizontal platforms160, which are labeled as platforms160a,160b, and160cdepending on their location within tissue compartment150. Tissue digester100creates a net upward vertical flow through tissue compartment150(and through the sub-compartments), although in alternate embodiments tissue digester100creates a net downward vertical flow, or an alternating net upward and new downward flow through tissue compartment150(and through the sub-compartments). Platforms160are configured to permit fluid to flow vertically (for example, in the upward direction) within tissue compartment150. In the depicted embodiment, the platforms160are screen-like structures that allow fluid to flow through each horizontal platform160while inhibiting undigested tissue of a minimum size or larger from moving through each horizontal platform160. In certain embodiments, the platforms160are substantially horizontal panels having perforations to permit fluid flow vertically through the platforms160.

Each horizontal platform160is supported by one or more platform supports162, which are labeled as supports162a,162b, and162cdepending on their location within tissue compartment150. In the illustrated embodiment platform supports162are depicted as being pegs that are received by complementary receptacles on horizontal platforms160, which act together to help properly position platforms160horizontally and vertically within tissue compartment150.

Optionally located within tissue compartment150are one or more vertically oriented partitions, for example, one or more vertical separators164. One or more vertical separators164may be used to separate the interior of tissue compartment150into multiple smaller tissue holding sub-compartments and may be solid, may include one or more apertures, and may resemble screen-like structures. For illustration purposes, there are six (6) tissue holding sub-compartments (labeled151athrough151f) depicted inFIG. 5. Each vertical separator164maintains its position during operation of tissue digester100to preserve the integrity of each of the smaller tissue holding sub-compartments. For example, each vertical separator164registers with a vertical wall engagement location166of platform support162to secure vertical separator164in position during the digestion process. Vertical separator supports168as best shown onFIG. 6, which in one embodiment resemble a comb-like structure, are optionally located within tissue compartment150to provide additional support for vertical separators164, such as to provide additional horizontal support for vertical separators160and to inhibit horizontal movement of vertical separators164during digestion.

Platform supports162are grouped at various locations within tissue compartment150to support the horizontal platforms160at various locations within tissue compartment150. For example, in the embodiment depicted inFIG. 5, the lowest of the three groupings of platform supports162are depicted as platform supports162aand denote the lowest level at which a horizontal platform160may be supported within tissue compartment150. Platform supports162bare arranged to support a horizontal platform160at a second position within tissue compartment150, and platform supports162care arranged to support a horizontal platform160at the uppermost position within tissue compartment150. Alternate embodiments include a single location or dual locations for positioning the horizontal platforms (a single grouping or two groupings of platform supports162), while other embodiments include four or more locations to meet various user needs.

Tissue digester100further includes operating valves106(seeFIGS. 5 and 6), which may include a back flush valve, a discharge ball valve and/or hot and cold water valves. In the depicted embodiment, the operating valves106are located in the housing140below the fluid vessel146. Access to operating valves106may be accomplished by removing one or more of the access panels142.

A temperature sensor170, which in one embodiment takes the form of a thermocouple, may be included to control the temperature of the fluid within fluid vessel146.

A pressure sensor172may also be included to automatically control the fluid level within tissue digester100.

In operation, a user places a horizontal platform160within tissue compartment150to support tissue during the digestion process. Typically, at least one horizontal platform160awill be placed at the lowest position within tissue compartment150and supported by platform supports162a, so that tissue may be loaded at the lowest point within the tissue digester. This lowest level horizontal platform160atypically remains in position and engaged with platform supports162aunless removal of this lowest level platform160ais required for cleaning. Other horizontal platforms (e.g.,160band160c) may also be placed in tissue compartment150as needed depending on the amount of animal tissue to be digested.

Tissue, for example animal mortalities, is initially weighed and loaded onto a horizontal platform160, such as horizontal platform160a. Vertical separators164may optionally be inserted to separate various groups of tissue. For example, if a number of household pets are being digested and the owners wish to keep the remains (i.e. ashes) of the individual pets, each pet can be loaded into an individual tissue digestion sub-compartment separated vertically by horizontal platforms160and separated horizontally by vertical separators164.

If tissue is loaded onto horizontal platform160aonly, thereby requiring only the lower portion of tissue compartment150to be used for digestion, baffle154would be removed to allow the digestion fluid to pass from tissue compartment150to pump intake plenum144through opening152. As such, the fluid flows into pump intake plenum144at an intermediate portion of plenum144, and at lower level than if baffle154was positioned to cover opening152, thereby facilitating the use of less digestive fluid than the amount required to run a fully loaded tissue compartment150. Horizontal platform160bwould typically be used to hold tissue within tissue compartment150and inhibit the tissue from moving into intermediate opening152, which could either block intermediate opening152or allow tissue to enter pump intake plenum144and potentially foul fluid pump112.

If more tissue than can be positioned on a single platform is to be digested (i.e., there is more tissue than can be held by horizontal platform160a), additional tissue may be loaded onto another platform, e.g. horizontal platform160b. Horizontal platform160ccould also be positioned to hold tissue within tissue compartment150. If required, additional vertical separators164could be installed between horizontal platforms160band160cto separate various groupings of tissue.

When horizontal platform160bis used to hold tissue, baffle154is typically positioned to block opening152, which in the illustrated embodiment is accomplished by sliding baffle154from an upper open position to a lower closed position. In this configuration, the digestive fluid will flow upward until reaching upper opening156, and then flow through upper opening156into pump intake plenum144.

For bulk processing of large amounts of tissue, such as when processing a single large carcass or a number of carcasses that do not need to be segregated, the tissue is placed on horizontal platform160a, baffle154is positioned to block opening152, and horizontal platform160cis placed in tissue compartment150to prevent tissue from entering pump intake plenum144. A sufficient amount of digestive fluid is then added to permit the digestive fluid to flow from tissue compartment150to pump intake plenum144through upper opening156and the digestive cycle is activated.

As can be appreciated from the above discussion, tissue digester may be arranged in multiple configurations to accommodate multiple requirements and processing scenarios.

Once the tissue is loaded, alkali is added in proportion to the weight of the tissue to be processed. A dry chemical may be added or, in other embodiments, a pump may add liquid chemical into the fluid vessel146. After addition of the alkali, lid102is closed and latched. The user may then activate the digestion process by using, for example, control box104. An automatic safety latch to maintain lid102in a closed position may optionally be included to prevent the user from accidently opening the tissue digester during digestion, which could result in the user being sprayed with digesting fluid. Tissue digester100then introduces water (hot or cold) into fluid vessel146until the proper volume is reached, at which point pump112is activated to circulate digesting fluid within fluid vessel146.

As best shown inFIG. 5, fluid is pulled downwardly from the pump intake plenum144through the pump112, which in the illustrated embodiment is a ducted propeller, and is moved to the bottom area146aof the fluid vessel146. The fluid flows along the bottom146aof fluid vessel146, which is optionally curved in the illustrated embodiment, and upwardly along the angled bottom146′ to horizontal platform160a. The fluid travels upwardly through the tissue compartment150, passing through the screen-like platform160aand all about the animal carcasses, lifting and moving the tissue around as the fluid circulates. The fluid then proceeds upwardly through platform160b.

If baffle154is not positioned over intermediate opening152, which typically corresponds to the situation where tissue is positioned on horizontal platform160aonly, the digestive fluid will flow out through intermediate opening152and back into the pump intake plenum144.

If the baffle154is positioned over opening152, which typically corresponds to the situation where tissue is positioned on horizontal platforms160aand160b, the fluid continues to flow upwardly through platform160c. Once the fluid passes the uppermost horizontal platform160, it flows out through upper opening156and back into the intake plenum144. The fluid level within compartment150may be slightly higher on the end opposite the opening152or156due to the flow pattern generated by pump112.

During operation, the fluid continues to circulate as the apparatus optionally heats the fluid (via heater158), and once the fluid reaches its predetermined operating temperature (for example, 199 degrees Fahrenheit), the system continues for a specified time (for example, 16 hours after reaching the predetermined operating temperature) to digest the animal tissue. Once the digestion cycle is complete, an optional CO2injection may be used to reduce the pH level of the digestion fluid. The fluid may then be back-flushed through the discharge port114to dislodge bone powder residues that may have settled and accumulated in the discharge port114. Once the discharge port114is clear, the drain valve115may be opened. A cold water co-flush may also be used to cool the wastewater while draining. Fluid discharge temperature is monitored and reduced during discharge via a discharge temperature sensor, such as thermocouple117.

Once the fluid vessel146is drained, it may be filled with fresh water and the fresh water circulated to rinse out any effluent residues. After the fresh-water rinse, the drain may again be back-flushed then opened to discharge the rinse water. A spray ball (not shown) optionally disposed in the lid102may be activated to provide a final rinse to the bone residues. This final rinse water may also go to drain.

When the digestion process is complete, the optional automatic safety latch can release and a control screen on the control box104can indicate to the user that the lid102may be safely opened. A hand spray nozzle (similar to a domestic kitchen sink sprayer) is optionally available for additional rinsing as needed. The bone remains may then be removed from within the housing.

Although the illustrated embodiments depict a single intermediate opening152in wall148, alternate embodiments include two or more intermediate openings152in wall148. Each intermediate opening152may be selectively blocked by a baffle154, such as by sliding baffle downward into an orientation that covers opening152. When tissue compartment150is at least partially filled with fluid to digest tissue, the fluid level will be at or above one or more openings152. Fluid will flow readily through the openings152that are not blocked by a baffle154, and fluid will be inhibited from flowing through the openings154that are blocked by a baffle154. By selecting which openings152are blocked and which are not blocked, the location at which fluid enters the pump intake plenum144from tissue compartment150can be controlled. Each intermediate opening152is typically sized to permit a flow of fluid from tissue compartment150to intake plenum144that is sufficient to avoid cavitation of pump112.

In situations where tissue digester100is to be filled to its maximum fluid capacity, which corresponds to the fluid level reaching upper opening156, each intermediate opening152will typically be blocked by its respective baffle154. In this configuration, the digestive fluid will flow upward until reaching upper opening156, and then flow through upper opening156into pump intake plenum144.

If less than the maximum fluid level is desired, the opening152corresponding to the desired fluid level in tissue compartment150will typically remain unblocked by a baffle154, while the openings152located below the fluid level in tissue compartment150are typically covered by their respective baffle(s)154. This configuration encourages upward movement of the fluid in tissue compartment150until reaching the maximum fluid level, at which point the fluid travels through an unblocked opening152and into pump intake plenum144. This upward movement tends to lift the tissue off the horizontal platforms160, helping the tissue move and encouraging rapid and complete digestion.

Depicted inFIGS. 11-16is a tissue digester200according to another embodiment of the present disclosure. Various components of tissue digester200are the same as corresponding components of tissue digester100except as otherwise indicated or illustrated, similar components being reflected by use of similar reference numbers or by similar depiction in the figures. In place of (or, in some embodiments, in addition to) the internal partitioning and baffling system located within tissue compartment150of tissue digester100, tissue digester200includes one or more baskets180. Each basket180includes side panels181and a bottom panel182(which is optionally removable). An upper panel183serves as a removable upper lid for basket180. Basket(s)180and upper panel183optionally include handles184to assist the user in handling upper panel183.

Panels181,182, and183may be solid or perforated with one or more apertures; however, in one particular embodiment side panels181are solid while bottom panel182and upper panel183are perforated with multiple apertures to form screen-like structures. One feature of the solid side panels181is their tendency to channel digestive fluid vertically through basket180. In one embodiment the perforations in the bottom panel182and/or upper panel183are ⅜ inches in diameter, although in alternate embodiments the diameter of the perforations are approximately ⅛ inch (which may have advantages in retaining smaller pieces of tissue within the basket while increasing the uniformity of the vertical flow throughout basket180and throughout each sub-compartment). Depicted inFIG. 15is an example embodiment of a bottom panel182with perforations sized and distributed to create a uniform vertical flow of fluid through basket180, and through the sub-compartments located between side panels181in basket180if utilized. In at least one embodiment, the upper panel183includes perforations as depicted inFIG. 15

Tissue digester200also includes a fluid pump112′ with a propeller that has been extended downward a few inches (e.g., 2 inches) from the position of the propeller in fluid pump112to increase the efficiency of fluid pump112′. In one particular embodiment, the propeller is located below the propeller's ducting.

One or more tissue separators (e.g., baffles188) may be selectively inserted into the interior portion each basket180. In some embodiments, an attachment mechanism, for example, one or more channels186, are used to position baffles118within basket180. When positioned within the interior of a basket180, baffle(s)188form individual compartments into which tissue (for example, animal carcasses) may be placed for digestion.

In some embodiments, a basket extension (sometimes referred to as a filler box) may be utilized to provide upward extensions of side panels181. For example, in the embodiment depicted inFIG. 16, basket extension190is similar to basket180and includes four side panels191(which may be similar to side panels181), but basket extension190does not include a bottom panel. In some embodiments the basket extension190includes mechanisms (for example, channels similar to channels186) for attaching baffles, while other embodiments (such as the depicted embodiment) do not include such mechanisms.

Use of baskets180in tissue digester200allow the user to create a plurality of configurations for digesting tissue. For example, one configuration is formed by placing a single basket180, which may have been further compartmentalized with one or more baffles188, in the bottom portion of tissue digester200. After loading the tissue into basket180(which may be accomplished prior to or after inserting basket180into tissue digester200) the user may place an upper panel183atop basket180and open baffle154in wall148. After positioning upper panel183atop basket180, the user may simply place solid (usually in powder form) alkali on the top of the upper panel183prior to closing tissue digester200and initiating the digestion cycle. This configuration digests a reduced amount of tissue with a reduced amount of fluid that circulates through basket180, through intermediate opening152, and back to fluid pump112, although in other embodiments the fluid can circulate in the opposite direction.

Another configuration is formed by the user placing two baskets180, either or both of which may have been further compartmentalized with one or more baffles188, into tissue digester200. After placing tissue within the lower basket180(which may occur before or after loading the lower basket180into tissue digester200), the upper basket180is placed on top of (or connected to) the lower basket180. The bottom panel182of the upper basket180will separate the bottom basket180from the upper basket180(acting as an upper panel for the lower basket180) and inhibits tissue from migrating between the two baskets180. Nevertheless, alternate embodiments include placement of an upper panel183on the lower basket180prior to placing the upper basket180atop the lower basket180. After loading tissue into the upper basket180, an upper panel183may be positioned over the upper basket180to inhibit tissue from migrating out the top of the upper basket180. When utilizing baskets with solid side panels181, it is possible to leave the intermediate opening152unblocked by baffle154without significantly affecting the performance of tissue digester200since, at least in part, the solid side panels181channel a sufficient amount of the digestive fluid through both baskets180to effectively digest the tissue within both baskets. This configuration digests an increased amount of tissue over the previously described configuration with fluid circulating through lower basket180, upper basket180, through upper opening156(and possibly also through intermediate opening152), and back to fluid pump112, although in other embodiments the fluid can circulate in the opposite direction.

Still another configuration is formed by the user placing a single basket180, which may have been further compartmentalized with one or more baffles188, in the bottom portion of tissue digester200. Either before or after placing the single basket180within the tissue digester to hundred, a basket extension may be placed on (or connected to) the upper portion of basket180, effectively extending the side panels181of the basket180upward. Since the effective height basket180is extended by using the basket extension, large animals may be placed into basket180. An upper panel183may be placed over the top of the basket extension prior to beginning a digestion cycle. In this configuration it is possible to leave the intermediate opening152unblocked by baffle154without significantly affecting the performance of tissue digester200. This configuration can digest larger animals than the previously described configurations with fluid circulating through lower basket180, basket extension.

While digesting tissue, advantages may be realized by moving digestive fluid slowly through tissue digester100or200to preserve the integrity of the bones during the digestive cycle. If too rapid a circulation is utilized, the bones will disintegrate leaving nothing to return to the owner of the deceased animal. In one example embodiment, a flow rate of approximately 500 gallons per minute produces a gentle enough flow to preserve the integrity of the bones. Additional advantages may be realized by flowing digestive fluid upward past the tissue as this assists in moving the tissue and increasing the rate of digestion.

In still further embodiments, a porous bag (such as one constructed of a non-digestible material such as nylon) may be utilized to further compartmentalize tissue digester100or200.

While illustrated examples, representative embodiments and specific forms of the invention have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive or limiting. The description of particular features in one embodiment does not imply that those particular features are necessarily limited to that one embodiment. Features of one embodiment may be used in combination with features of other embodiments as would be understood by one of ordinary skill in the art, whether or not explicitly described as such. Exemplary embodiments have been shown and described, and all changes and modifications that come within the spirit of the invention are desired to be protected.