CN1028069C - Ashptic food processing apparatus and method - Google Patents

Abstract

The present invention provides an aseptic food processing apparatus which is greatly improved and is capable of pumping food, and an aseptic food processing method. The present invention provides accurate, uniform and aseptic cooking conditions (e.g., time, temperature and pressure) and preserves the integrity of particulates in the food product at the same time. A stable and relatively high systematic pressure can be obtained by combining a down stream metering device and an upper stream constant pressure pump. Meanwhile, an accurate temperature control is carried out, and the partial steam flash evaporation inside the apparatus, which has harmful effect on the product quality is eliminated. By adopting the aseptic food processing apparatus and method, aseptic processing to heterogeneous phase food materials with low acidity, such as stewing food and pungent food can be safely carried out in an industrial scale.

Description

Ashptic food processing apparatus and method

The present invention briefly relates to a kind of relevant available pump conveying, particularly the significant improvement equipment of the sterile processing process of the heterogeneous food of low acidity.More particularly, invention relates to so a kind of method and apparatus, this equipment is to make the product flow rate constant by one, and the upstream that places heat exchanger and the metering device of holding material pipe downstream and to be placed on flow process makes food material stream keep basically that the device of constant voltage is common to be formed.

A plant-scale traditional tinned food processing method and a tinning method are the can of earlier selected raw-food material being packed in general, subsequently can is sealed, and and then under the condition that heats up and pressurize, this tinned food is used the Steam Heating quite a while.Such processing method was used many years, yet but still had many great difficulties.For example, the cost of this can process is considerable, and this is not only because the consumption of this process energy is big, and for filling food containers head in being suitable for loading the seasonal period of tinned food, must section store the can of a large amount of various costlinesses earlier.In addition, cause the organoleptic attribute (as: taste, color and uniform particles) of food to decay inevitably for the needed quite harsh conditions of cooking of cooker head food.

Therefore, food processor improves the organoleptic attribute and the nutritive value of food for when reducing cost, and has worked out the method that some improve food processing in the several years in the past.In these methods, there is a suggestion will adopt so-called sterile processing and packing exactly.Say that briefly handle for food being carried out asepticize, process need comprise the packing continuously cooking process in order to sterilize before, and packs subsequently under aseptic condition.The technology of sterile processing food is developed in 1940's at first.But just in recent years, food processors just begin this technology of extensive use.Compare with the tinned food processing technology that custom is adopted, the advantage of sterile food processing is many-sided, for example: can cut down the consumption of energy and packing cost, and have higher processing speed.In addition, this sometimes method is improved the effect of food organoleptic attribute in addition.

The sterile processing of food mainly concentrates on the homogeneous phase of a class as pudding and fruit juice or the product aspect of fluidised form at present.In addition, the many kinds in this series products all have stronger acidity (pH＜4.6), and wherein needed boiling temperature and digestion time are all lower and few.And in this case, food is owing to processing is handled to such an extent that the improper toxic action to the person that produces can be ignored.

The sterile processing process of the high acidity food of this homogeneous phase generally comprises the decontamination system that uses a pressurization and asepticize.There is a positive displacement pump that raw-food material juice amount is also transported continuously to processing sections the front of this system.Processing workshop section comprises that heat exchanger that one or more is elongated and one section retain the pipeline of food in order to the centre, also have a series of cooling heat exchangers in order to cooling food at last.Generally also be equipped with pneumatic backpressure valve to produce certain throttling action and to keep the pressure of system in the downstream of processing sections.

Claim in the management rules of related food sterile processing: asepticize (sterilization) process of food material stream should be decided by their time one temperature conditions in holding the material pipe.Therefore, food is heated to the needed time of sterilising temp being arranged in the heat exchanger of holding material pipe front, and the time that is stopped in their what its pipelines in office just can not count.Therefore, in order to set up a safety,, guarantee that the accuracy of time one temperature relation of food in holding the material pipe is extremely important in industrial feasible process.

At present relevant management rules are also stipulated: measuring pump must be placed in the upstream of holding the material pipe, and must make the material can be in needed flow rate current downflow.Therefore, the metering system of front material enter the heat exchanger of taking the lead and hold the material pipe before, the flow rate of food material under the upstream extremity of system of processing must measure (that is,, all constant product flowrate should be able to be arranged) no matter how pressure changes thereafter.

Above-mentioned system can provide satisfied result for the stronger homogeneous phase food material of acidity, and still, this system is for as soup stock, stew, and the more weak heterogeneous food of the such class acidity of pungent food then is extremely invalid.For example, the existence of backpressure valve is unallowable for heterogeneous food in fact in the system.Because food material can produce sizable blocking action in by this valve, thereby making to be smashed to pieces inevitably by the food particle of this valve degrades, sometimes even mashed.So the someone advises adopting the device of other type to process the heterogeneous food of processing faintly acid.One of them suggestion is exactly to adopt a revolving positive displacement pump to replace being positioned at the backpressure valve in processing sections downstream.Because the service speed of downstream pump is lower than preposition measuring pump, therefore formed system pressure.Another idea is exactly to adopt a sterile pressurized surge tank to reach the purpose that produces system pressure.Though these two kinds of methods can realize low acidity, heterogeneous food are carried out sterile processing theoretically, all have very serious defective.In fact, existing these major defects are so to be difficult to overcome so that up to the present, industrial yet there are no that a cover adopts this class idea low acidity, heterogeneous food are carried out the equipment of sterile processing.Even if in order to reach industrialized purpose, people have extremely extensive interest for this class technology of exploitation and equipment, situation also still like this.

The subject matter of above-mentioned technology is before boiling and holding the material section, promptly just measures the problem of food material flow at the upstream extremity of equipment.No matter also promptly how pressure condition all must the constant material flow rate of generation for this metering method.In any industrialized production process, for the flow rate that makes food material keeps constant, the change of normal material output all will cause measuring pump to increase or reduce identical pressure; In this case, the pressure variation is inevitable.It should be noted that because the pulsation of this pressure may cause the local flash distillation of steam generation in the boiling heat exchanger.So general usual practice is that system pressure is maintained a little higher than steam desired pressure of flash distillation (for example than preventing that the needed pressure of flash distillation from exceeding 0.069-0.106MPa) under the boiling temperature of being got that prevents.If but the system pressure fluctuation is too big, as this situation that measuring pump is contained in the upstream, this is contingent, and promptly Zhuan Zhi some some areas also may be not enough to stop the pressure state that produces flash distillation.As a result, the steam flash distillation has been come out, and food then " has boiled " in steaming plant.This not only can destroy food material needed steady and continuous flowing when the equipment, and even more serious be that its consequence also may cause the granule materials fragmentation to degrade.This flash distillation of what is more important also can change for temperature relation of necessary important time one of aseptic boiling, even also may cause the product of non-sterilization.

To one of this problem possible solution be simply system pressure is brought up to one be enough to compensate in any typical operation operate under the high pressure of the normal pressure pulsation that may run into.Yet this suggestion may cause another difficult problem again: owing in common equipment, adopt so high pressure to tend to cause harsh processing conditions, and cause the food decomposition to degrade.Therefore food processor just makes oneself to be absorbed in a dilemma condition as when the measuring pump of constant flow rate is used in boiling and the upstream of holding the material pipe unit.Promptly on the one hand, if system pressure is only remained under the situation of a little higher than flashing pressure, because the inevitable pressure fluctuation that the upstream measuring pump is brought may cause the generation of local flash distillation.And on the other hand, use higher relatively pressure for fear of any local flash distillation takes place, but this fact itself just may cause degrading of food.

The present invention has overcome these above-mentioned difficulties, and provides a kind of available pump is carried, and particularly as the heterogeneous food of low acidity of soup class, stew and pungent food one class, carries out the equipment that significant improvement is arranged of sterile processing.Put it briefly, the invention provides a cover can carry out the food material of a kind of available pump conveying of sterile processing and boiling continuously under pressurized conditions equipment.This equipment comprises that a cover carries the positive pressure pump of moving material stream with the pressure of substantial constant, and the continuous processing device that matches of constant voltage conveying device therewith.Comprise in this processing unit (plant) such as one in order to the moving material stream of pressurization is heated to the indirect heat exchanger of needed processing temperature, and place this heater downstream keep the device of a period of time in order to the material flow that will pressurize and heat, the effect of this device is to guarantee that food material realizes aseptic boiling.At last, for the food material that makes the equipment of leaving can keep the flow rate of substantial constant, complete equipment be provided with in the downstream of holding materials device one with the crew-served metering device of processing unit (plant).

In satisfied especially a collection of structure, preferably select the device of a reciprocating piston pump for use as the constant voltage pumping.The double acting piston pump that use kansas, u.s.a city (Kansas) Oran-Parker's (Overland Park) Marlen research company is produced has been obtained good especially result.This pump can operated under the constant compression force pattern or under the pattern of constant flow rate.But according to needs of the present invention, this pumping installations needs to operate under the pattern of constant pressure.Marlen formula pumping installations is at United States Patent (USP) 4,097, is described in 962.We have quoted this patent data for reference only specially in the present patent application.

Carry out indirect heat exchange in order to make continuous pressurization food material flow same thermal medium (as the water vapour of partition), thereby food material stream is heated to needed boiling temperature, and the device of heated food material preferably includes one or more indirect heat exchanger.At this, the indirect heat exchanger that can adopt can be miscellaneous, yet for many concrete processing conditions, finds that already it is the most suitable scraping the formula heat exchanger of pulling.

As constitute a whole food processing apparatus part what hold that materials device adopts is used traditionally structure, it is to have the elongated pipe material of holding of certain size to be constituted by one basically, its effect is to make therein the material flow that moves continuously keep a period of time, is enough to during this period of time guarantee that food material is finished consumes and sterile processing.

Except these above-mentioned process, typical processing unit (plant) also should be included in food material by holding after the material pipe cooling device that makes it to cool off.Here preferentially adopt indirect cooling heat exchanger once more.In this case, cooling medium adopts cooling water often.

As previously mentioned, the downstream metering device preferably adopts rotary pump, and for example the Waukesha by Abex company casts those devices that branch provided.The function of this metering device is to make the food material stream that has carried out aseptic boiling in the downstream of holding the material section to be kept constant flow rate.It promptly is the main cause that the present invention can obtain excellent achievement that this downstream metering device and upstream constant pressure pump conveying device combine.

Fig. 1 is the general flowchart of sterile processing equipment of the present invention.

Fig. 2 is the simple flow process similar with Fig. 1, but the system of sterile processing equipment wherein adopts two systems of processing parallel with one another.

Fig. 3 then be the part sectioned view of the preferential reciprocating piston pump conveying device that adopts, in the actual food product first being processed system being carried out disinfection with hot water also is to adopt this device.

These figure are carefully looked in backspace now, Fig. 1 especially, and sterile processing equipment 10 roughly comprises the following device and system, that is: in order to the upstream constant pressure pump 12 of the continuous food material stream that produces substantial constant pressure; Continuous processing device 14; Downstream metering device 16; And at last with the numeral 18 disinfection with hot water systems that schematically illustrate.Say to such an extent that know again a little, be equivalent to U.S. Patent number 4,097, the sort of pump described in 962 at the pump shown in Fig. 1 12.This pump (see figure 3) comprises a material chamber 20, have in material chamber the inside a pair of can be reciprocal, tubular sleeve 22 and 24 placed side by side.Two pistons 26 and 28 by the fluid dynamic operation place corresponding tubular sleeve 22 and 24 respectively.The port of export in material chamber 20 has a pair of feed pipe 30 and 32, and they communicate with tubular sleeve 22 and 24 with pipeline respectively.Feed pipe 30 and 32 the port of export and a reversal valve 34 join.In the reversal valve back then is from pumping installations delivery outlet pipe 36 with material.Also comprise a pair of pneumatically-operated penstock 38 and 40 at the equipment shown in Fig. 3, this two valve connects with corresponding feed pipe 30 and 32 mutual street in operation; About the important function of this two valve (38 and 40), will explain afterwards.

Processing unit (plant) 14 comprises that scraping that one or more designs routinely pull formula heat exchanger 42, and a material inlet pipe 44 and a material outlet pipe 46 are arranged on the heat exchanger.In addition, heat exchanger is provided with external jacket, thereby the effect of external jacket system passes to steam or other heat transferring medium heats the material that passes through heat exchanger inside.It all is universal that certain these are scraped the formula heat exchanger of pulling, and the user can buy by various channels.

Processing unit (plant) 14 comprises that also an elongated insulation holds material pipe 48, and this size of holding the material pipe should stop certain hour to guarantee to realize aseptic boiling therein even as big as making food material.The same with heat exchanger noted earlier, also be completely normal, and right and wrong Changshu is known for those skilled in the art.

In processing unit (plant) 14 in the arranged downstream of holding material pipe 48 cooling device.This cooling device comprises that a series of scraping pull formula heat exchanger 50 and 52.Just as shown in FIG., heat exchanger is to be one another in series to join.For cooling effectively by the food material in the heat exchanger, cooling heat exchanger need comprise that one allows the structure (in figure do not represent this part structure) of cooling medium (as cooling water) by external jacket.

As previously mentioned, the design of pump 12 is to make it under the pressure of substantial constant continuous material flow is sent to processing unit (plant) 14.For this reason, between the inlet tube 44 of the outlet 36 of pump 12 and boiling heat exchanger 42, connect with suitable pipeline 54.Similarly, pipeline 56 is in order to outlet that connects heat exchanger 42 and the inlet tube of holding material pipe 48.With the exception of this, also need a pipeline be used for will hold the port of export and the cooling heat exchanger 50 and 52 of material pipe 48 couple together, at last, in order will to cool off and to be sent to measuring pump 16 through the good food material of sterile processing, the outlet in heat exchanger 50 and 52 is connected to outlet conduit 58.

As shown in scheming to go up, pump 16 links to each other with pipeline 58, then is connected to a triple valve 62 by pipeline 60 after pump 16.As shown in fig. 1, valve 62 can be opened the food material that processes with transmission and arrive conventional sterile packaging machine.Because the operation of pump 16 is to be to measure the food material flow, guarantees that just the flow rate of material can remain basically unchanged, like this, food stream just is sent to packing machine with sustained flow rate by pipeline 60 and valve 62.

Equipment shown in Fig. 1 also comprises the decontamination system 18 of water.In order to reach this purpose, between valve 62 and foregoing penstock 38 and 40, be connected with pipeline 64.(these penstocks link to each other with 12).Pipeline 64 is communicated with an interstation again and connects cooling heat exchanger 66, also is connected with triple valve 68 and check-valves 70 thereafter.At last, water source 72 links to each other with valve 68, has a surge tank (constant voltage jar) 74 to link to each other with pipeline 64 in the running between valve 68 and check-valves 70.

When device 10 runnings, by reinstating the disinfective action that system 18 realizes equipment.Under this operator scheme (being the operator scheme that water carries out system's sterilization), pump 12 is used as a feed pump.For this reason, need sleeve 22 is seen Fig. 3 with 24() prolong, and be fixed in the material chamber 20.Valve 68 is opened so that water can be by water source 72 inflow pumps 12.Open valve 62 to connect pipeline 60 and 64.During water carried out disinfection, valve 38 and the 40 round actions with piston 26 and 28 opened and closed successively, at first water are drawn in tubular sleeve 22 and 24, subsequently, because not stopping transport of piston is moving, water is arranged through pipeline 30 and 32 again, and water just can inject decontamination system fully like this.

The water of pumping was heated in heat exchanger 42 in cycle period, and by holding material pipe 48 and cooling heat exchanger 50 and 52.Water and then by pipeline 58 and pump 16 feeds heat exchanger 66 at last.In this heat exchanger, the same cooling medium of the disinfectant of circulation (as cooling water) carries out indirect heat exchange and is cooled off.In some cases, heat exchanger 66 can not wanted yet.

After having finished disinfecting steps, (the general available 144 ℃ hot water of this operation circulated 30 minutes), system has obtained preheating, and has been aseptic.In other words, all are ready, can feed food material.At this moment water system should be turned off, and material is directly delivered to pump 12.Under this operator scheme, tubular sleeve 22 and 24 ties up to material chamber 20 interior back and forth movements so that in turn the food material filling is advanced in the sleeve by the regular hour pass.Finish dash fill out after, piston 26 is just arranged material with 28 motion and is delivered to processing unit (plant) 14 through carrier pipe 30,32 and valve 34.The front is mentioned, and during carrying food material with pump, pump 12 is to be under the pattern of constant voltage operation, so can produce the moving material stream of substantial constant pressure.In fact, by means of the Marlen pump of preferentially being selected for use, the pressure condition of operation can maintain with selected rated pressure differ less than approximately ± level of 0.035MPa on.Under the common situation, to adopt system pressure about 0.35-1.06MPa for the most desirable.

Under any circumstance, the material flow of constant pressure always at first by the heat exchanger 42 of heating usefulness, is heated to desired temperature at this with material.Under the situation of the low acidity food of processing, this temperature is taken as about 132-149 ℃ usually.After material heats in heat exchanger, deliver to by pipeline 56 and to hold material pipe 48.The size system of holding the material pipe is designed to allow the food material stream of the interior continuous motion of pipe be able to keep time enough under boiling temperature, thereby guarantees to realize aseptic boiling.Say that briefly this time range approximately is about 10 seconds to 20 minute.For most food processing conditions, this section is held the material time and is approximately about 30 seconds to 1.5 minute.

Well-done food leave hold material pipe 48 after, feed cooling heat exchanger 50 and 52.Be cooled to satisfy the needed temperature of packing at this food material, this temperature generally is taken as 21-27 ℃.Material after cooling off enters measuring pump 16 by pipeline 58 then, and this measuring pump is guaranteed can flow out processing unit (plant) 14 with constant flow rate through aseptic well-done food.Subsequently, these foods valve 62(this valve under this operational circumstances of flowing through is opened) be discharged to sterile packaging machine (packing machine does not show in the drawings).

Fig. 2 represents another kind of specific embodiment of the present invention, and wherein adopting a single pump 12 is the two groups of 14a of processing unit (plant) branch and 14b feed in parallel mutually.Since these two independently processing unit (plant) section 14a and 14b substantially be consistent at the device shown in Fig. 1 14, except the symbol of in addition " a " and " b ", all be to adopt here similarly with reference to number.In all cases, the represented device of respective digital is identical among the device that similar numeral marked and Fig. 1.Under any circumstance, can see all that single pump 12 is by pipeline 54,54a and 54b link to each other with the processing unit (plant) 14a and the 14b of parallel connection.So corresponding material affluent-dividing just as the situation that Fig. 1 described, carries out boiling, is incubated and holds material and cooling by processing unit (plant) son field 14a and 14b one by one.Each back of two machining cells all respectively meets each rotary metering pump 16a and 16b.

The effect of these pumps is identical with corresponding pump 16 described in Fig. 1.But only drive this two pump 16a and 16b simultaneously here with a motor 76.Under this situation, in fact two pumps turn round under identical rotating speed, thereby guarantee substantially the same with the flow rate of two bursts of material flow of 14b from processing unit (plant) son field 14a respectively.In addition, owing to only adopted a pump 12, be identical basically with pressure condition in the 14b therefore at two processing unit (plant) son field 14a.Come material stream passed piping 60a and the 60b of self-pumping 16a and 16b to deliver to a public carrier pipe 78.Valve 62 is connected in the pipeline 78.Deliver to sterile packaging machine by the homologue materials flow that processing unit (plant) son field 14a parallel with one another and 14b send out through valve 62.

Can see in addition, also comprise a water disinfection system 18 in the equipment of Fig. 2.Similar with foregoing situation, and with reference to Fig. 1, identical parts are to compile with identical number.The method of operating of the water system in the method for operating of the water system in Fig. 2 equipment and Fig. 1 equipment also is identical.

According to adopting consistent the showing of actual tests that equipment provided by the invention carried out, the present invention is used to process obtains uniform good result when containing the low heterogeneous material of acidity of the such class of food of particle such as stew and other.In one group of such test, employing has Marlen 700 type double acting piston pumps that material chamber and fluid (waterpower) the drive constant pressure pump as the upstream, and face is scraped the heat exchanger of pulling the formula indirect heat exchange heat exchanger as boiling (with steam as heat medium) and cooling (with water as cooling medium) usefulness with Alfa-Laval.Waukesha133A or 25RF(be not with the material chamber) positive displacement pump as measuring equipment.Getting the diameter of holding the material pipe is 50.8 meters, and its total length is 2.81 meters, and total capacity is 4.92 * 10 ^-3Rice ³, and the placement that is inclined upwardly.The food of being tested comprises simmered beef, chicken noodles, and seafood food, and sweet and sour pork etc.Several food in duration of test production all prove to have to be had identical with the tinned food of common production or than they better quality.Particularly with the integrality of architectural feature, uniform particles and the formation of the taste of food, food itself etc. during as the standard of measurement quality quality, this conclusion is just particularly evident.And generally always be better than the food that obtains with boiling method usually with the particle color and luster of the food that the present invention produced, and the color and luster of its condiments and thick gravy is much light.The boiling temperature that is adopted is 144 ℃ in test, and cooking pressure then remains on about about 0.69-0.83MPa.Material is 1 minute in the time of holding the material stop.

Although the preferential metering device that adopts of the present invention is a rotary pump, the present invention is not subjected to this restriction.In multiple alternative mode, can adopt a kind of device for filling of positive displacement to replace rotary food material flow rate to guarantee to provide constant.

Claims (10)

1, pumpable low acidity, heterogeneous food material are carried out continuously and the equipment of sterile processing and boiling adding to depress, it is characterized in that this equipment comprises:

Carry the constant pressure pump device (12) of described processed food material flow continuously with constant pressure;

The continuous processing device (14) that matches with said constant pressure pump device in the operation, comprising the said continuous food material stream that has pressurizeed is heated to the heater (42) of needed processing temperature and be arranged on this heater downstream and with said heating pressurization material flow keep a period of time with guarantee to food material stream carry out aseptic boiling hold material section (48) and

Place said holding to expect the section downstream and keep constant metering device so that leave the food material flow rate of this equipment with said processing unit (plant) compounding practice.

2, equipment according to claim 1 is characterized in that said constant pressure pump device is the constant voltage reciprocating piston pump.

3, equipment according to claim 1 is characterized in that said heater is to allow the indirect heat exchanger (42) of the continuous food material of said pressurization stream and heat medium indirect heat exchange.

4, equipment according to claim 1 is characterized in that described heat exchanger (42) is the indirect changing-over device of scraper-type.

5, equipment according to claim 1 is characterized in that the said elongated material pipe (48) of holding that the said heater of material Duan Weiyu links to each other of holding.

6, equipment according to claim 1 is characterized in that said processing unit (plant) comprises to be arranged on the said cooling device (50,52) of holding the pipe material downstream.

7, equipment according to claim 6, it is characterized in that said cooling device be one or many interstations connect heat exchanger (50,52).

8, equipment according to claim 1 is characterized in that said metering device is the rotary pump metering device.

9, equipment according to claim 1 is characterized in that wherein also comprising the disinfection with hot water system (18) with said pumping installations and processing unit (plant) compounding practice.

10, according to any one described equipment among the claim 1-9, it is characterized in that said processing unit (plant) comprise many parallel with one another and can with (the 14a of processing unit (plant) branch of said pumping installations compounding practice, 14b), wherein each said branch comprise with the continuous affluent-dividing of the pressurization of said food material be heated to requirement processing temperature heater and be arranged on this heater downstream and keep a period of time to guarantee holding the material section said heating pressurization material affluent-dividing what this material affluent-dividing carried out aseptic boiling.

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