DE102004013934A1 - Filtering plant, for purifying oils or fats used in food and also frying oil, comprises a pumping unit, a prefiltering unit and a filtering unit, where the pumping unit is connected before or after the filtering unit - Google Patents

Abstract

Filtering plant (1) (I), for purifying oils or fats used in food, comprises a pumping unit (20), for the oils or fats, and a filtering unit (30), where the pumping unit is connected before or after the filtering unit and the impurities that affect the foam development and/or the taste quality and/or aromatic characteristics and/or reducing the induction time of the oils or fats are removed. An independent claim is also included for a method of purifying oils or fats that are useful in food comprising applying pressure to the oils or fats and removing the impurities (that affect the foam development and/or the taste quality and/or aromatic characteristics and/or reducing the induction time of the oils or fats) before or after applying pressure.

Description

The The present invention relates to a filter system for cleaning of oils and fats that are useful in food, in particular of edible oils, which are used for frying.

heated frying oils arrive at the preparation of food as fried food Commitment. As fried food, e.g. Potatoes, pieces of meat and Vegetable pieces used. A batch of cooking oil is used for the successive preparation of a variety of pieces used the fried food. As part of the frying oil on or in the deep-frying piece remains, reduces the remaining oil in the frying container. On the other hand, contaminate Particles of frying pieces the frying oil increasingly. Also the environmental conditions, e.g. humidity, have an influence on the quality of the frying oil. To the Consumption of cooking oil To limit, so far, a replacement of the frying oil in a predetermined periods or after the preparation of a predetermined amount of fried food. This is the frying oil completely replaced.

The Preparation of frying pieces in frying oil, in the already other frying pieces have been prepared, has the consequence that residues of the previous frying pieces, the for example, may already be charred and toxic substances and unwanted Have odor, adhere to the later introduced Frittierstücken. Accordingly, the sensory qualities of the later introduced frying pieces and there may be a health risk.

Out The prior art already has cleaning devices for engines and gear oils As well as diesel fuels known that a pre-filter, a pump and a fine filter. Such cleaning devices are typically used to clean oil below 50 ° C. The focus such cleaning is due to the filtering out of particles, which makes a wear more mobile Cause parts, and of water, for example, by the Combustion process is generated. Due to the special design the filter on the conditions of oil in engineering and due the heightened quality requirements in the case of foods, in particular foods prepared by heating, it is not possible to use the cleaning devices for motor and gear oils for food.

The Object of the present invention is the disadvantages to eliminate the prior art and a filter system or a Procedure for cleaning oils and fats to be used in foodstuffs the frequency the total exchange of oil can be reduced and maintain quality of the oil over a long period of time can be. It also aims to improve the quality of food with this oil be prepared, kept constant. In addition, the frying process by the cleaning process with the filter system not in undesirable Be restricted.

These The object is achieved by a filter system according to claim 1 and a method solved according to claim 15.

The inventive filter system has a pumping device for the oils and fats and one of the pumping device upstream or downstream Filter device. By this filter device are contaminants in the oils or fats that cause foaming and / or taste quality and / or the odor properties of the oils or fats and / or the induction time of the oils or Reduce fats, remove. As a result, oils and fats are extended with one Induction time, i. with higher quality receive. Thus, the frying oil over a long period of time can not but only the loss will be replaced, with only small residues of impurities in frying oil available.

Of the Filter device is preferably preceded by a prefilter device, through the coarse particles in the oil or fat are separable. In this way damage to the Avoid pumping through coarse particles in the oil. The pre-filter device preferably removes components up to 50 microns, thereby adding the Filter device delayed is and a good efficiency of the pumping device under consideration the pre-filter device located in the suction mode is achieved.

It is favorable if the filter device carries out a cleaning of the oil or fat up to 3 μm, preferably up to 2 μm. Due to the small size of the remaining particles in the oil or fat particles toxic substances and undesirable odorant in the oil or fat can be formed to a lesser extent and surfactants and polymers are removed to a large extent. For such a result, the filter in the filter device preferably comprises cotton and pulp, more preferably activated carbon and teflon silk. With such substances, a thermostable filter can be produced over a wide temperature range Filtering secures. However, the filter may have any other composition adapted to the composition of the oil and / or the impurities.

With the filter system according to the invention can preferably oils or fats with a temperature of up to 180 ° C to be cleaned, which the Cleaning of frying oil when using this, i. while deep-frying, allowed.

The to be cleaned oils or fats are advantageously usable in the preparation of food, which in addition to the cleaning of oils or fats that are part of the food, including cleaning of oils or fats possible in which the food is introduced for preparation, preferably heated become.

Of the Use of the present invention can be applied to oils or fats with at least 80 ° C limited be, whereby the filter device in a favorable manner for a high temperature range.

The preferred use of the invention is in the purification of Frying oil. This is preferably cleaned in the bypass, whereby the frying process must not be interrupted and at the same time a high oil quality and quality of the prepared Food can be hedged.

The Filter device preferably removes water as impurities and food residues, so that the foaming of the purified oil is reduced is and sooted Particle new fried food can not affect.

Corresponding the method according to the invention pressurization of the oils or fats and, prior to or downstream, filtering the oils or fats to degrade the quality Impurities from the oil or remove fat. In the method, the above are preferred regarding the Device cited Restricting features applicable.

Further developments according to the invention are the subject of the dependent claims.

The The present invention will become apparent with reference to the accompanying drawings described in which:

1 shows a schematic, perspective view of the filter system according to the invention according to a first embodiment,

2 is a schematic representation of the operation of a superfine filter or a filter device, and

3 a perspective view of the ultrafine filter according to the invention.

below The present invention will be described in detail.

1 shows schematically the filter system according to the invention, for cleaning oils and fats, which are used in food. As the oil to be cleaned, for example, vegetable oil, olive oil, rapeseed oil, rock oil, pumpkin seed oil, edible oil, frying oil are usable. The oil may be cold frying oil or heated frying oil. In this case, the temperature range for the heated cooking oil to be cleaned is preferably in the range of 80 to 200 ° C, more preferably at maximum 180 ° C, and most preferably in the range of 150 to 170 ° C.

The Cleaning of frying oil through the filter system according to the invention can be done in offline mode, i. with fryer off, the temperature of the frying oil is lower than the frying temperature is and for example, the room temperature. In this case can the inlet and the outlet of the filter system discharge into a frying container. alternative can do this at the filter plant a storage for contaminated oil and a Memory for purified oil be provided so that the contaminated oil in the filter system is done, the filtering and after a certain time the purified oil is removed. This is especially advantageous if too little in the vicinity of the fryers Space is provided to the heated cooking oil, in the frying pieces to be prepared and that is in the deep-frying container.

The Advantages of the filter system according to the invention are particularly strong when they are used to clean heated cooking oil is used. The filter system is operated in bypass, i.e. that the inlet and the outlet of this in the frypot the fryer open, preferably with a big one Distance, so that the boisterous cleaned oil is not mixed with the sucked in oil to be cleaned to a large extent.

following will affect the oil and summarizing the fat in the cleaning process as a liquid based.

The filter system 1 has a prefilter 10 , a pump 20 and a fine filter 30 on.

The pre-filter 10 , the pump 20 and the fine filter 30 are preferably mounted on a common base plate, through which a simple transport of the filter system according to the invention is possible. This base plate can either be placed on a caddy or even has feet and / or transport wheels over which a shift of the filter system is possible. Due to the ease of transportability of the filter system according to the invention, it can be brought to any location with little effort, for example, to the frying a large kitchen. In the case of offline operation, the storage means for liquid to be cleaned and purified liquid may be attached to the caddy.

The example provided with a housing made of polypropylene pre-filter 10 preferably performs a mechanical filtration of the liquid to be cleaned and has, for example, a washable wire mesh with a dirt pick-up of about 500g and a power of about 35 l / h. The mesh size of the wire filter insert is in the range of 30 to 50 microns, preferably about 32 microns. The pre-filter 10 operates preferably in the suction mode, so that mechanical impurities in the liquid to be cleaned, through the pre-filter 10 be removed, do not interfere with the functioning of the pump.

The liquid to be purified passes from an inlet port 2 via a connecting cable 4 to the pre-filter and is preferably cleaned in this, mechanical components.

When exiting the pre-filter, the viscosity of the liquid should preferably be at most 150 mm ² / s, to ensure trouble-free operation of the pump 20 make sure. The liquid leaving the pre-filter is supplied via a pump connection line 5 the pump 20 fed.

The pump 20 is preferably a thermostable pump of any type, which is operable in the temperature range of 20 to 200 ° C. For example, the pump is an external gear or internal gear pump. Due to the heat-resistant design of the pump 20 is to pay particular attention to the type of shaft seal, which may be a PTFE / carbon radial seal, for example, to prevent leakage. The outlet pressure is for example at most 5 bar, more preferably 4.5 bar, to a sufficient pressure for the micro-filter 30 to provide and implosion of the downstream ultrafine filter 30 to avoid.

The pressure connection of the pump 20 is over a gauge 21 at which the discharge pressure of the pump is displayed, whereby an undesirable pressure is detected at an early stage. With the pressure connection of the pump 20 is also via a Feinstfilter connection cable 22 a pressure relief valve 23 connected to the outlet port 3 via a connecting cable 24 is connected and responds, for example at about 5 bar. Parallel to the pressure relief valve 23 is the finest filter 30 intended. In this way, through the pressure relief valve 23 an undesirable pressure difference at the micro-filter 30 be avoided.

The finest filter 30 is preferably a membrane filter for microfiltration. 30 shows the basic structure of a superfine filter, as used by Kleenoil Filtration Limited, South Milford, Leeds, United Kingdom, in cross-section. The basic construction of the ultrafine filter according to the invention is comparable.

The ultrafine filter has a preferably cylindrical filter housing 31 on, with the over a fixing screw 34 a filter cover 32 is connected and in the bottom in the axial direction of an inlet port 35 is trained. The fixing screw 34 is preferably in the middle in the filter cover 32 provided and in the filter housing 31 screwed. The fixing screw 34 radially surrounding is an insertion channel 38 provided for the liquid, which in the radial direction through an inner wall 33a a filter cartridge 33 is limited and into a distribution cavity 38 passing through the filter cover 32 is limited, opens and the via the entry port 35 the the pump 20 leaving liquid is supplied.

The filter cartridge 33 is in the, preferably made of metal, filter housing 31 sealed in such a way that liquid in the distribution cavity 38 only through the filter cartridge 33 to the axially opposite portion of the filter cartridge 33 arrives. On to the filter cover 32 opposite section of the filter cartridge 33 are preferably annular Flüssigkeitsaustrittsnuten 39 in the filter housing 31 provided to the out of the filter cartridge 33 leaking purified liquid to a liquid outlet 36 to guide the axially in the filter housing 31 is provided.

In the 3 in a perspective view shown filter cartridge 33 comprises cotton, pulp and preferably activated carbon and Teflon silk and is formed, for example, in the form of a tightly wound wood-containing paper with long fibers, so that water is absorbed by the paper and unwanted particles such as food leftovers on this, but the liquid, such as frying oil that can pass filter cartridge. The structure of the filter cartridge 33 and also the finest filter 30 is not limited to the above configuration, but may be adjusted depending on the liquid to be filtered and the impurities contained in the liquid.

The filter cartridge 33 of the ultrafine filter 30 filters out bound water, which causes the surfactant-induced foaming in the heated frying oil. Furthermore, through the filter cartridge 33 Also, breadcrumbs and other food residues, including polymers and surfactants that cause the formation of unwanted odors, retained, thereby improving the taste quality of frying oil. After filtering through the fine filter 30 Only suspended particles smaller than 3 microns, more preferably less than 2 microns, remain in the frying oil.

The water absorption of the ultrafine filter 30 is preferably at most 500 ml, the dirt pickup preferably at most 1 kg and the filter power preferably at most 168 l / h to achieve a satisfactory cleaning.

Residual oils from the Filtering can preferably mixed in an amount of 0.5 to 1% diesel or fuel oil so that these are residual oils can be recycled without separate disposal.

According to the invention oils or Fats that can be used in food, by a procedure Pre-filtering, pressurization by means of pump and ultrafine filters cleaned.

following be a test arrangement and the test results in relation to the cleaning effect of the filter system according to the invention accordingly the first embodiment described above.

The Experimental setup had a prefilter for separating coarse Frying residues, a pump and a microfilter for separation of the smallest particles as described above on. The filtration was carried out at a flow rate of 0.6 l / min. Used cooking oil, that for 12 hours at 180 ° C for the Deep-frying of mainly potatoes and Wiener schnitzel used and that was suitable for frying vegetable oil without additives, was sucked off the bottom of a 10-liter canister. The filtrate was then returned to the canister. It was filtered for 2 hours, with the freshly filtered oil with the unfiltered oil was mixed.

The used oil was dark and contained frying residues from the mentioned foods.

in the Result has been shown that the used oil has been completely clarified because no visible particles or cloudiness templates.

at the subsequent Stability investigation Statements on the stability of the oil were determined by means of Ranzimat. Were at 120 ° C 20 l of air per minute through the oil blown, resulting in a strong oxidation. The following is the induction time, i.e. the time to a strong increase in the oxidation, of filtered and unfiltered oil compared.

As from the above table was the induction time of used oil due Deep frying greatly reduced, which also on the oil Residues, like bread crumbs and potato pieces is due. Furthermore, charred particles have already been observed in the used oil, removed according to the invention were.

The extended Induction time with filtered oil indicates an improvement in oil quality.

Further could when heated, filtered oil Lower foaming could be observed and could be done in the microscope no particles larger than 3 μm observed become.

Consequently is the filtration according to the invention of oil then particularly advantageous if the frying oil at a high consumption over a longer Period not complete replaced, but only the frying loss is replaced. there As a result of filtration, particles are also removed which are the cause for unwanted substances to be in the oil can. It will be so by the regular removal of food residues from the frying oil toxic substances, such as e.g. carcinogenic heterocyclic aromatic amines, and undesirable odorant, when heating high protein foods such as e.g. Potatoes and meat are produced, to a lesser extent.

It let yourself thus with a supplement the frying loss by fresh oil and the filtering according to the invention an increase the oil quality and a longer Durability until the entire oil exchange achieve.

at an inventive second embodiment, not shown the pre-filter is integrated into the micro-filter, preferably the prefilter is located above the ultrafine filter and is preferably the pre-filter upstream of the pump and the micro-filter of the pump downstream. Such an arrangement can reduce the space requirement, so that increased Number of fields of use, such as Fryers in kitchens with little space, available stands.

The The present invention thus relates to a filter system for Cleaning of oils or fats that can be used in food. This filter system has a filter device and a pumping device, whereby the sensory and qualitative properties of food interfering Substances in the oils or fats at least partially removable from the oils or fats are. The preferred use of the invention is in the purification of heated oils or Fats, in particular frying oil.

Claims (15)

Filter system ( 1 ) for cleaning oils or fats which can be used in foods, with a pump device ( 20 ) for the oils or fats, and a filter device ( 30 ), the pumping device ( 20 ) is upstream or downstream and is removable with the impurities in the oils or fats which affect the foaming and / or flavor quality and / or odor properties of the oils or fats and / or reduce the induction time of the oils or fats. Filter system according to claim 1 with a prefilter device ( 10 ), through which the oils or fats of the pumping device ( 20 ), the pressurized oils or greases of the filter device ( 30 ) by the pumping device ( 20 ) are zulleitbar. Filter system according to claim 2, wherein the prefilter device ( 10 ) the contaminants of substantially up to 50 microns are removable. Filter installation according to one of the preceding claims, wherein the filter device ( 30 ) the impurities conditions of substantially up to 3 microns, preferably up to 2 microns, are removable. Filter installation according to one of the preceding claims, wherein the filter device ( 30 ) has a filter that has cotton and pulp. Filter device according to claim 5, wherein the filter device ( 30 ) further comprises activated carbon and teflon silk. Filter unit according to one of the preceding claims, which is designed in such a way that this for cleaning of oils or fats having a temperature of up to 180 ° C, can be used. Filter unit according to one of the preceding claims, wherein the oils or fats can be used in the preparation of food. Filter system according to claim 8, wherein the oils or Fats in the preparation of food under heat can be used Filter unit according to one of the preceding claims, which is designed in such a way that this for cleaning of oils or fats having a temperature of at least 80 ° C, can be used. Filter system according to one of the preceding claims Cleaning of frying oil. Filter systems according to one of the preceding claims, wherein the contaminants passing through the filter device ( 30 ) are water and / or food leftovers. Filter systems according to one of the preceding claims, wherein the filtering by the filter device ( 30 ) with respect to a frying process in the oils or fats to be cleaned in the bypass. Filter system according to claim 2 or according to one of claims 3 to 13, when dependent on claim 2, wherein the prefilter device and the filter device in one piece are formed. Process for cleaning oils or fats involved in food can be used, with the steps: Pressurizing the oils or Greases, and before or after pressurization filtering the oils or fats to remove the impurities in the oils or fats that cause foaming and / or the taste quality and / or the odor properties of the oils or fats and / or the induction time of the oils or reduce fats.