Modular fermenting tank for biogas production by wet fermentation

Abstract

A modular fermenting tank for production of biogas by wet fermentation consisting of a shell comprising input and output chamber separated by a wall, input and output pipe of these chambers, and mounting input ports to each chamber, wherein the shell of the fermenting tank consists of an inner shell of the fermenting tank being in direct contact with an organic substrate, wherein the inner shell is flexibly fitted in an outer shell of the fermenting tank, wherein a thermally insulating material is placed between the inner shell and the outer shell. The outer lateral walls of the input chamber and of the output chamber are provided with circulating nozzles for agitating of the organic substrate and liquids, wherein the chambers are favourably provided with a watering manifold, heating tubes, and overflow collecting edge connected to a collecting drain. The chambers of the fermenting tank are provided by the ceiling with cameras and reflectors. The shell of the fermenting tank is provided with auxiliary inputs for dosing of auxiliary substances to both chambers of the fermenting tank.

Description

[0001] Modular fermenting tank for biogas production by wet fermentation

[0002] Field of the invention

[0003] The present invention relates to a fermenting tank for a biogas plant. The invention is embodied as a mobile vessel device that can be used to transform biomass into energy, and it is installed in a low-substrate source location and does not require much electricity.

[0004] Background of the invention

[0005] Increasingly, biogas fermenting plants are being built to process bio-waste and biodegradable municipal waste. These plants are built in two technological variants: dry or wet fermentation. Each technology poses its benefits and drawbacks, and is used for different substrates.

[0006] The wet fermentation process is relevant for the purposes of the present application. The most frequently employed method involves processing of input material in the form of a liquid capable of being pumped with an average dry matter content of up to about 12%. It is a continuous biological process running in big airtight agitated vessels - modular fermenting tanks, which may be arranged horizontally, vertically, or in combination. A substrate is conveniently dosed to the tanks continuously. In the fermenting tanks, steady temperature of about 35°C up to 41°C is maintained under mesophilic conditions, or about 55°C up to 60°C under thermophilic conditions. The thermophilic process is characterized in deeper disintegration of organic matter, higher biogas production, but lower process stability. The process operates within a specific, stable status, and as such, fundamental operating parameters must be observed. Some of them need to be taken into account already during the design stage: the size of fermentors and their efficiency (depending on agitation), loading of fermentors with organic matter input, concentration of ammonia nitrogen in the fermentors.

[0007] People have known about the process of making biogas and producing methane using organic substances for more than 2,000 years. Owing to increasing disparity between energy demand and supply for people, various renewable energy systems have been developed, however, the primary concerns include energy costs and safety, as well as release of harmful gas and other pollutants from the conventional energy production methods. These have resulted in a broad spectrum of technological advances in the domain of alternative energy sources. One of the alternative energy sources is therefore biomass for the energy production, which has become globally attractive as a clean and sustainable energy source.

[0008] Over the last decades, there have been many attempts to build biogas stations or systems that produce biogas on a large scale and meet the requirements of the industry and companies.

[0009] These systems have typically been associated with high cost, complexity, inefficient agitation, lower yields, and abnormal functioning under different climatic conditions. To date, it has not been possible to provide the user with a ready-made fermenting tank in a biogas system to facilitate plug-and-play operation; such systems have included assembling of various components or equipment on site, further making installations laborious.

[0010] Biogas digester tanks operate by mixing a substrate with various reactants in the inner biogas vessel and causing wear on the agitator blades, therefore the digester tank consumes a large amount of energy in the agitating process, resulting in higher operating costs.

[0011] Technical solutions of the prior art are those known for example from CN 101760366 or US 2020 / 0172449. In the prior art solutions, the agitation of input materials inside the fermenting tank is time-consuming, because it occurs at a lesser extent and makes it ineffective. In said technical solutions, a volume for agitation of feeding materials is a connection pipe between the tanks or fermenting chamber, and at a later time in the tanks by agitators or naturally, wherein agitation of the feeding materials occurs ineffectively, which results in lower yield of the biogas production. The conventional fermenting tanks have focused on agitating of the substrates using a pressure difference by controlling their flow through the pipe and therefore, no continuity in agitation of the substrate is achieved, and effective agitation of the substrate is also not provided.

[0012] Common fermentation tanks have heating systems placed inside to maintain a favourable internal temperature during the agitation of the substrates and the production of the biogas, but after such heating systems are used continuously for a certain period of time, a certain amount of substrate or biomass sticks to the elements of the heating system and forms a thick layer, which further acts as an insulating layer causing a reduction in the heating rate, thereby rendering the heating system ineffective due to the failure caused by the formation of a thick layer. The operation of the heating system placed inside the fermenting tank also causes problems for repair works of the fermenting tanks.

[0013] These technologies for converting of the biomass into energy require a permanent installation on site, and most of them are primarily used for large substrate sources (in the order of higher tens of tons per day).

[0014] The closest related art of the present solution is the biogas production facility according to WO 2011 / 077358 A3 and then also according to WO / 2021 / 152628A1. These technical solutions use a double-chamber fermenting tank with a PON (Power of Nature) agitating system, and they are provided with an auxiliary immersed pump-based agitating system. According to said patents, the fermenting tank for biogas production includes: an outer wall provided with at least one input for the biomass delivery and at least one output for the produced biogas output, wherein the outer wall comprises two interconnected vessels, each configured for transfer and exchange of the biomass with the adjacent vessel using a blending mechanism for biogas production, and at least one agitator capable of allowing natural and continuous self-agitation of the biomass in the interconnected vessels without the need of any discrete energy source to ensure the biomass is mixed for the required period of time. Said interconnected vessels are divided by a partitioning wall placed vertically in a sealed volume and designed to be provided with a plurality of perforations to provide the method for natural effective agitation of the biomass between the adjacent interconnected vessels.

[0015] The technical solution known from WO 2011 / 077358 A3 is time-consuming for building permit as well as subsequent construction. It requires the need for special concrete surface treatments for corrosive substrates (slurry, special wastes from specific plants), but even so, the service life of the concrete structure is reduced. The need for special technological procedures is associated with an increased carbon footprint due to the construction technology (formwork, concreting, construction waste). Upon commissioning, the technical solution does not allow scaling the system up by another fermenting tank. Also, easy dismantlement and recommissioning elsewhere is not possible and therefore, the technical solution has zero second usage at another site. Also, the plant has difficult and technologically complex thermal insulation of the plant as a whole.

[0016] Some drawbacks from WO 2011 / 077358 A3 are eliminated by WO 2021 / 152628 Al, where factory series production as well as scalability may be applied, meaning that the fermenting tanks can be added or removed according to the customer's needs. The technical solution can also be flexibly handled on site, easily dismantled and put back into operation elsewhere. Thanks to its low construction readiness requirements, installation is possible within a few days. However, neither this technical solution is perfect. A steel construction of the fermenting tank requires special surface treatment of the internal metal walls of the fermenting tank to ensure corrosion resistance. However, this resistance may not be fully provided. The required special surface treatment of the internal metal walls of the fermenting tank is highly susceptible to scratching, and thus to coat distortion and to corrosion. The entire design of the technical solution has a high thermal transmittance, which results in increased thermal energy requirements / ineflficiency of thermal (thermic) energy management.

[0017] For all known fermenting tanks, the outer wall consists of a single shell, which is either made of concrete (in the case of a tank usually located in the ground) or a steel shell. Both materials degrade and deteriorate on contact with aggressive organic substrates. There are also significant heat losses between the fermenting tank and the surrounding environment, which makes the fermentation process less efficient and requires additional heating and therefore increased operating costs.

[0018] The inventor's object was to develop a fermenting tank solution that consists of installing a portable, modular, easy-to-assemble device of a size suitable for a decentralized solution for small biomass sources (units of tons / day). Also, the object was to design a plant that operates under reduced energy consumption to effectively minimize operating costs, as well as the plant with low maintenance costs and a short maintenance time required. It is further an object of the present invention to provide a method of producing biogas that increases the extent of blending of the biomass within the digester, thereby maximizing biogas production. Last but not least, the inventor's object was to devise a solution whose interior, which comes into contact with the organic substrate, does not suffer under its chemical aggressiveness, and also a solution which, in order to save the need for additional energy, does not have such energy losses with the surrounding environment, thanks to which it works effectively under a wide range of climatic conditions. Summary of the invention

[0019] Said drawbacks are eliminated by a modular fermenting tank for biogas production by wet fermentation consisting of a shell that provides the tank divided into an input chamber with an input pipe and an output chamber with an output pipe, wherein both the chambers are interconnected in upper part by a biogas blending pipe having upturned U shape and separated by a vertical perforated partitioning wall, and furthermore consisting of an mounting input ports to each of the chamber, wherein the mounting input ports are located in a ceiling of the shell, characterized according to the present invention in that the shell of the fermenting tank consists of an inner shell of the fermenting tank, which is in direct contact with an organic substrate, wherein the inner shell is fitted in a flexible way in an outer shell of the fermenting tank, wherein a thermally insulating material is placed between the inner shell and the outer shell.

[0020] Favourably, the outer lateral walls of the input chamber and of the output chamber are provided with circulating nozzles to agitate the organic substrate and liquids. The input chamber and the output chamber may be provided at their ceiling with a watering manifold to distribute and moist a dry crust created on the level of the liquid organic substrate, wherein the chambers are further provided at the perforated partition wall with heating tubes fitted upstream from the circulating nozzle, wherein both chambers are provided in their upper part at the substrate level with an overflow collecting edge connected to a collecting drain.

[0021] In each of the chambers there may be cameras attached on the ceiling by the perforated partition wall to visually check agitation and liquid level surface, to continuously monitor the substrate level, and to shoot both chambers of the fermenting tank. Additional reflector may be provided for the cameras.

[0022] The outer shell of the fermenting tank is favourably provided with auxiliary inputs for dosing of auxiliary substances to both chambers of the fermenting tank, wherein both inputs are located next to the mounting input ports.

[0023] The advantage of the invention lies in several fundamental considerations that make the operation of the fermenting tank a more efficient and economical device compared to the competitive state of the art.

[0024] The double shell design of the fermenting tank reduces heat loss and permits use of a different material for the inner shell and for the outer shell. For the inner shell, a plastic material being resistant to aggressive chemical environment of the organic substrate is usually used. Owing to the reduction of heat loss and insulation of the outer environment, the substrate is heated much better, and the biogas is produced faster, and the need for additional energy to heat the substrate is reduced. The circulating nozzles in the technical solution provide improved circulation of the substrate and its constant motion, which helps to avoid crusting on the surface. Even in the case of the formation of such a crust, the technical solution is provided with a watering manifold that moistens and softens the hard crust, which then sets it in motion again or causes it to pulp or sink. The advantages of the technical solution is its outstanding maintenance-free design or elimination of repeated entry inside the fermenting tank thanks to the installed cameras and additional reflectors, if any. Auxiliary substances may be dosed to the chambers of the fermenting tank due to the input for dosing of the auxiliary substances without the internal environment of the fermenting tank being lost (loss of the generated biogas).

[0025] The aim of the modular fermenting tank is to build highly standardized biogas plants operating on the principle of continuous wet fermentation. The modularity is characterized in pre-arrangement of industrially prefabricated modules supplied to a customer and installed in a couple of days. In this regard, the plant may be easily installed, scaled up or scaled down. The main object of the present invention is to use the biomass at place of its origin to produce the biogas with the downstream production of electricity and heat, and to refine otherwise waste inputs into bio methane and bio fertilizers. The modular fermenting tanks are of various sizes and transportable on roads. The whole empty fermenting tank may be handled by a crane.

[0026] Explanation of drawings

[0027] The invention will be explained in detail using a drawing, in which Figure 1 illustrates a cross section of the fermenting tank with indication of all its components. Fig. 2 illustrates a view on the outer rear wall of the fermenting tank. Fig. 3 illustrates a view on the upper outer wall of the outer shell of the fermenting tank. Exemplary embodiment of the invention

[0028] A pre-arranged biomass of a organic substrate enters to an inner shell 1 of a fermenting tank through an input pipe 3, wherein the shell 1 is made from a homopolymer plastic material (HP plastic material) and fitted in an outer shell 2 made from a steel supporting frame 2. The inner shell 1 of the fermenting tank is divided into two chambers, an input chamber a of the fermenting tank and an output chamber lb of the fermenting tank. The input chamber la and the output chamber lb of the fermenting tank are vertically separated by a perforated partitioning wall 7 and at the same time, they are interconnected by an blending pipe 5 having shape of upturned “U” in ceiling of the fermenting tank close to the partitioning wall 7 as well as ports in the perforated partitioning wall 7 and the interconnection pipe and overflow edge fixtures 10 and fixtures 11 from the fermenting tank.

[0029] The plastic inner shell 1 of the fermenting tank is totally resistant to corrosion and its lifecycle is approximated to be more than 25 years.

[0030] After the organic substrate enters the input chamber la of the fermenting tank, the surface levels between the input chamber la of the fermenting tank and the output chamber lb of the fermenting tank are automatically levelled through the perforated partitioning wall 7. The partitioning wall 7 is perforated at its lower portion by the bottom of the chambers la, lb, and the perforation includes three ports.

[0031] The excessive and residual contents of the substrate flows out by the output pipe 4 of the output chamber 1 of the fermenting tank. The agitation of the substrate occurs, among others, by an agitation assembly consisting of a screw pump 13 located on the rear outer side of the fermenting tank, circulating nozzles 9 placed in both chambers la, lb of the fermenting tank on their outer walls, and two substrate suction types for the screw pump 13 through control fixtures, in particular for the first suction type by the fixture 10 of a overflow collecting edge 8a where the fixture 10 conducts the substrate from a collecting drain 8b located by the overflow collecting edge 8a placed in both chambers la, lb of the fermenting tank on the perforated partitioning wall 7. The suction from the collecting drain 8b permits circulation of the substrate clumps and crusts, if any, and injection thereof to the volume of both chambers la, lb of the fermenting tank by the circulating nozzles 9, and for the second suction type by the fixtures 11 from the fermenting tank that collect water from the volume of both chambers la, lb of the fermenting tank.

[0032] Displacement of the screw pump 13 flows to the circulating nozzles 9, however to either the first or the second chamber la, lb of the fermenting tank. A watering manifold 14 is connected from the displacement pipe line of the screw pump 13. The watering manifold 14 moisturizes surface of the fermenting tank level in case a dry crust is created.

[0033] Cameras 12 that scan the surface level of both chambers la, lb of the fermenting tank, are placed on the ceiling near the partitioning wall 7 to continuously monitor the substrate levels in both chambers la, lb of the fermenting tank.

[0034] The structure of the double- wall fermenting tank comprises the inner shell 1 and the outer shell 2, wherein the inner shell 1 being in direct contact with the organic substrate is made from PP-H (Polystone P homopolymer) plastic material and flexibly fitted inside the outer shell 2 of the fermenting tank made from a steel frame. A thermally insulating material is placed between the inner shell 1 and the outer shell 2 of the fermenting tank. The static calculations and structure design are rated to working range of the fermenting tank at an outdoor temperature -25°C to +45°C and an internal substrate temperature 10°C to 45°C. The structure can handle expansion and shrinking of different materials used (plastic / metal) across the working temperatures. The plastic design of the inner shell 1 provides corrosion resistance compared to either concrete or stainless steel structures, and permits processing of highly corrosion aggressive substrates.

[0035] The screw pump 13 provides the required flow rate and the downstream circulating flow. Connection of the screw pump 13 permits two variants of the substrate suction:

[0036] 1) from the fermenting tank volume by the fixtures 11,

[0037] 2) from the overflow collecting edge 8a from the level by the fixtures 10.

[0038] Input ratio of the drawn substrate may be controlled via control valves of individual suction branches.

[0039] Primarily, the agitation of the organic substrate is provided by the PON system consisting of the partitioning wall 7 of the blending pipe 5. The agitation system is the main agitation system that reduces kW / h consumption required for operation of the plant in a rapid way. PON produces up to 10% more biogas than traditional mechanical agitating systems. The blending pipe 5 is used to pass the generated biogas which, when entering from the input chamber la to the output chamber lb, applies pressure on the digestate in the output chamber lb, which results in swinging the level, and therefore shifting of a part of the contents from the output chamber lb to the input chamber la through the perforated partitioning wall 7. This process does not require external added energy and provides agitation on the physical basis. The biogas flow through the blending pipe 5 is always only downstream from the input chamber la to the output chamber lb.

[0040] In addition, an auxiliary / starting agitation system is installed to agitate the substrate during commissioning of the fermenting tank. This is provided by two concepts of solution.

[0041] The first concept provides agitation by a propeller agitator 19, where the propeller agitators 19 are placed in each of the chambers la, lb in the upper half portion of their outer wall.

[0042] The second concept is a system of agitating circulating nozzles 9, the screw pump 13, the collecting edge 8a, the collecting drain 8b, and the control fixtures 10, 11, 20. The fixture 20 opts for preferential flow between the chambers la, lb and connects to the circulating nozzles 9 via a pipeline.

[0043] The overflow collecting edge 8a and the collecting drain 8b are placed on both sides of the perforated partitioning wall 7 towards each chamber la, lb and extend across the length of the partitioning wall 7. Considering the need to place the overflow collecting edge 8a above the average and regular digestate level, the placement of the overflow collecting edge 8a with the collecting drain 8b on the overflow edge 8a is made in the upper portion of the perforated partitioning wall 7 close to the ceiling of each chamber la, lb.

[0044] The variability of the agitating concepts provide a lot of options for processing and blending of different specific substrates with specific properties.

[0045] A heater element and function thereof as a breaker of the circulating flow:

[0046] A heating tube 15, which provides the required technological temperature of the mesophilic environment ranging from 36°C to 41°C for optimum disintegration of the organic substrates, is placed upstream the circulating nozzles 9 in order to break the flow and homogenize heated water in the volume of the fermenting tank. The heating tube is placed in each chamber la, lb near the perforated partitioning wall 7, i.e., on the opposite side of each chamber la, lb than the circulating nozzles 9. The heating tube 15 extends from the bottom of each chamber la, lb and has an unlimited height, however, extending above the digestate level is not desirable.

[0047] Solution to concerns related to potential crust or foam on the fermenting tank level:

[0048] The fermenting tank is provided in its upper short portion by the overflow collecting edge 8a with the collecting drain 8b under a theoretical overflow level. When either crust or foam creates, suction of the screw pump 13 is reconfigured using the fixtures 10 of the overflow edge to the suction from the overflow collecting edge 8a.

[0049] Circulating agitation motion of the substrate, which breaks when crossing across the heating tube 15, flows from lateral portions of the chambers la, lb of the fermenting tank to the collection drain 8b by the perforated partitioning wall 7.

[0050] Watering device:

[0051] The fermenting tank is provided with a surface level watering manifold 14 for when there is a need to disintegrate and moisturize the dry crust, which may occur in some cases on the digestate and prevents permeating of the biogas to a bag. The watering manifold 14 has form of a tube with nozzles extending across the width of both chambers la, lb of the fermenting tank.

[0052] The inputs 16 for dosing of auxiliary substances to both chambers la, lb of the fermenting tank are placed on the outer shell 2 of the fermenting tank next to the mounting input ports 6 and used for feeding of auxiliary substances (enzymes, bacteria, oils) to the fermenting tank without any heat and produced biogas loss inside the chambers la, lb of the fermenting tank. The input 16 comprises a pipe outlet DN 50 provided with a flange. A valveintermediate piece-valve-hopper / funnel is mounted on the flange to dose both loose as well as liquid auxiliary substances. Both the input 16 and the mounting input port 6 go through both shells 1, 2 of the fermenting tank inside the chambers la, lb. The mounting input ports 6 are provided with transparent visors.

[0053] Inspection monitoring cameras:

[0054] Cameras 12 are installed in both chambers la, lb of the fermenting tank to visually check the agitation status and the surface level. The cameras provided with a lighting reflector are provided on the perforated partitioning wall 7 in the volume of the inner shell 1 of the fermenting tank. The cameras 12 monitor the surface level area and the collecting drain 8b under 130° angle view.

[0055] The biogas generated in the fermenting tank accumulates in (not shown) gas bag being placed on the upper side of the fermenting tank and accessible via a safety ladder. The biogas bag is made from a heavy-duty and biogas-approved EPDM foil. The biogas enters through not shown gas duct in the ceiling of the output chamber lb of the fermenting tank.

[0056] Considering modularity of the technical solution, and therefore mutual serial connectivity, not all fermenting tanks may include the output to the external bag.

[0057] To clean the fermenting tank or to drain the digestate in case of an emergency, a discharge system is installed consisting of a discharge pipe 17 and a discharge valve 18, which are placed on the wall of the output chamber lb by the bottom thereof. The discharge valve 18 and the discharge pipe 17 act also as a safety feature.

[0058] Input substrates and fermenting of the digestate in the fermenting tank (process description)

[0059] A mixture of biodegradable organic substrate is fed to the input chamber la of the fermenting tank through the input pipe 3. The level is balanced based on the principle of communicating vessels through the perforated partitioning wall 7 between the input chamber la and output chamber kb. The organic digestate, which has already been fermented, exits through the output pipe 4.

[0060] For the fermenting process to operate correctly, agitating of the digestate must be provided under optimum operating conditions provided by the heating tubes 15 and the PON (Power of Nature) agitating system embodied by the blending pipe 5. If needed, auxiliary agitating systems are used depending on type of the input organic substrate either through the circulating nozzles 9, pump 13 or mechanical propeller agitator 19. During the fermenting process, the biogas generates and accumulates in the external bag.

[0061] Industrial applicability

[0062] The invention finds its place in all plants where biological waste is generated capable of being processed by the fermentation into a biogas component. The modular fermenting tank for the biogas production may be located near agricultural / farming production sites such as cow houses or pig farms, or industrial facilities where animal waste is generated at an elevated level, e.g., slaughterhouses. Other applicable plants include municipalities and processing of the biodegradable biomass by fermentation, including sludge from water treatment plant, and e.g., zoological gardens, composting plants.

[0063] In view of the current search for alternative and non-fossil fuels, the invention is also a green operation for island or community energy production.

[0064] List of reference numerals

[0065] 1 inner shell of the fermenting tank la input chamber of the fermenting tank lb output chamber of the fermenting tank

[0066] 2 outer shell of the fermenting tank

[0067] 3 input pipe

[0068] 4 output pipe

[0069] 5 blending pipe

[0070] 6 mounting input port

[0071] 7 perforated partitioning wall

[0072] 8a overflow collecting edge

[0073] 8b collecting drain

[0074] 9 circulating nozzles

[0075] 10 overflow edge fixture

[0076] 11 fixture from the fermenting tank

[0077] 12 camera

[0078] 13 screw pump

[0079] 14 watering manifold

[0080] 15 heating tube

[0081] 16 input for dosing of auxiliary substances

[0082] 17 discharge pipe

[0083] 18 discharge valve

[0084] 19 propeller agitator

[0085] 20 blending nozzle fixture

Claims

PATENT CLAIMS1. A modular fermenting tank for biogas production by wet fermentation consisting of a shell that provides the tank divided into an input chamber (la) with an input pipe (3) and an output chamber (lb) with an output pipe (4), wherein the chambers (la, lb) are interconnected in upper part by a blending pipe (5) having upturned U shape and separated by a vertical perforated partitioning wall (7), and furthermore consisting of an mounting input ports (6) to each of the chamber (la, lb), wherein the mounting input ports are located in a ceiling of the shell, characterized in that the shell of the fermenting tank consists of an inner shell (1) of the fermenting tank, which is in direct contact with an organic substrate, wherein the inner shell (1) is fitted in a flexible way in an outer shell (2) of the fermenting tank, wherein a thermally insulating mass is inserted between the inner shell (1) and the outer shell (2).

2. The fermenting tank according to claim 1 characterized in that the outer lateral walls of the input chamber (la) and of the output chamber (lb) are provided with circulating nozzles (9) to blend the organic substrate and liquids.

3. The fermenting tank according to claim 1 characterized in that the input chamber (la) and the output chamber (lb) are provided at their ceiling with a watering manifold (14) to distribute and moist a dry crust, wherein the chambers (la, lb) are further provided at the perforated partition wall (7) with heating tubes (15) fitted upstream from the circulating nozzles (9), wherein the chambers (la, lb) are provided in their upper part at the substrate level with an overflow collection edge (8a) connected to a collecting drain (8b).

4. The fermenting tank according to claim 1 characterized in that in each of the chambers (la, lb) there are cameras (12) attached on the ceiling by the perforated partition wall (7) to visually check agitation and the liquid level surface, to continuously monitor the substrate level, and to shoot both chambers (la, lb) of the fermenting tank.

5. The fermenting tank according to claim 4 characterized in that the cameras (12) are provided with a lighting reflector.

6. The fermenting tank according to claim 1 characterized in that the outer shell (2) of the fermenting tank is favourably provided with the auxiliary inputs (16) for dosing of auxiliary substances to both chambers (la, lb) of the fermenting tank, wherein both inputs (16) are located next to the mounting input ports (6).

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