CN103841841A

CN103841841A - System to improve icing problems in blast freezer tunnels

Info

Publication number: CN103841841A
Application number: CN201280048374.XA
Authority: CN
Inventors: T·杜布勒尔; D·帕捷
Original assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 2011-10-05
Filing date: 2012-09-04
Publication date: 2014-06-04
Also published as: US20150027140A1; EP2763556A1; WO2013050680A1; FR2980956B1; BR112014007701A2; FR2980956A1; AU2012320311A1

Abstract

A method and device for chilling food products by jets blasted into a tunnel, said tunnel comprising / a conveyor for conveying products into the tunnel, at least one plate, located opposite the conveyor, and provided with through holes, the plate or plates being located above and/or below the conveyor; and at least one means of blowing a cold fluid through the through holes and towards the products, characterized in that, during all or part of the periods of operation of the tunnel and/or during all or part of the periods of stoppage of the tunnel, there takes place an operation to clear all or part of said through holes, using a network of channels allowing a blow gas to be distributed opposite all of said through holes.

Description

Be used for the system of the ice formation issues of improving air blast freezing machine tunnel

Technical field

The present invention relates to utilize for example liquid nitrogen of cryogenic liquid direct or indirect injection and in the field of the method for tunnel type equipment cooling food.

Background technology

Conventionally, this tunnel comprises:

-be provided with the heat-insulating room of entrance and exit;

-for the device of conveying products between entrance and exit;

-for cryogenic liquid being introduced to the device of heat-insulating room, so that product directly contacts with this liquid (conventionally, this feedway comprises for injecting liquid into the house steward on product) or make product and this liquid mediate contact (this is commonly referred to " cold battery " in this area) by radiator refrigerant being injected in tunnel, cold is subject to and the impact of the exchange of tunnel internal air to the transmission of product, and this exchange is to be undertaken by the effect of the ventilation unit associated with each battery;

-and, cold air can be blown to through product on ventilation unit.

The one equipment of compact (taking ground minimal surface region) more and more effectively and especially more and is more economically being sought in food industry always.In many cases, this may be in the case of not investing the production capacity that improves appointed place new building.Therefore,, in order to improve production capacity in the space of reducing hold facility, recent freezer unit tunnel provides the technology becoming increasingly complex.

For this reason, recent high-performance equipment must improve and the heat transfer coefficient for the treatment of frozen product.In the situation that cold being passed to product from low-temperature receiver with cold air ventilation, conventional technology comprises the speed that improves this cold air.Then cold air is pressurizeed and is injected into the form (being commonly referred to " impact " in food industry) that directly strikes the jet on product.Heat transfer coefficient is therefore very high, and the refrigerating capacity of every cell list area is also very high.Document EP1449443A1 illustrates the prior art of this shock.

But this technology being highly profitable has defect and technical difficulty.In the time that the feature of ventilating system has been revised by the pollutant of ventilating system (frost or other deposits), ventilating power is difficult to control conventionally, especially true after some hours in work.

And air velocity and ventilation speed are very high, and it is asymmetric to observe the distribution of cold air, and this makes air enter and discharge at opposite side in a side of equipment.

Verified, frost mainly comes from the infiltration of extraneous air.These air penetrations from workshop to freezer unit tunnel are accompanied by entering of water vapour (from the moisture of air) certainly, and this water vapour will be deposited in machine with white form.Therefore, to poorly controlled excessive refrigeration and the extra production cost of not only causing of gas balance, also accelerate to have polluted the system of ventilating for the heat exchanger to producing the plate of blowing jet and may be provided with, this oneself who has caused this phenomenon amplifies.

The various schemes that enter to improve excessive frosting situation by restriction air have been proposed in the literature, especially:

-set up buffering area in tunnel portal/exit: this scheme addresses one of phenomenon of observing in this tunnel,, in the time that jet high-speed impact is on unique plate, some cold airs are discharged to outside tunnel, air capacity in tunnel is constant, and this has formed the infiltration of warm air automatically.Then the tunnel area that, product is loaded onto wherein still can not reduce air penetration " pipeline " in a large number as guiding air stream.

In one case, (or multiple) buffer area is positioned at the tight downstream of loading area, and in the second situation, be positioned at the tight upstream of tunnel exit, nonventilated buffering area passes through the expansion of tunnel shell (at the entrance and exit place of freezer unit, each region is expanded 1.5m to from 50cm), thereby formed the dead angle that suppresses gas velocity in every side, this has reduced entering and the discharge of cold air of air naturally.But the major defect of this system is, increase the overall dimensions of machine, this runs counter to adopting the initial effect of pursuing of blowing jet.

-using physical barriers: this scheme comprises the inlet/outlet place that plastics or stainless steel barrier is placed on to equipment.These barriers have in fact limited entering and the discharge of cold air of air.But although they are more effective, therefore they stoped air to enter freezer unit.In reality, they are almost invalid conventionally, because owing to being arranged in food passage, they can not seal inlet/outlet veritably.In addition, when they touch through food time, they produce hygienic issues sometimes.

-using gas shield: this scheme is included in tunnel portal and exit and installs for being suitable for compensating unbalance air and being blown into the system in tunnel.Very hour this system can provide satisfied result sometimes when unbalance, but on the other hand, and medium when highly unbalance when compensation, this system does not demonstrate the ability that re-establishes cold air balance.

But in food industry, the fact that must keep firmly in mind is, it is relevant that one of them of moisture enters some evaporations of water that source also itself comprises with the food entering, and the food entering for some is especially true.Therefore, the speed that frost occurs at air blast hole place is fast or slow, but it always there will be, and As time goes on the flow velocity of gas of injection reduce, just as the thermal efficiency of machine.

Then, be known that the scheme that has proposed in the literature other types, especially:

-on the plate of support holes, increase vibration source.If the strength of vibration is enough to frost to separate, it is favourable that this technology can prove.

But itself there are some defects in these strong vibrations: they make machine (weld seam, base, and for example electronic component of motor, temperature probe, sensor) variation.Also must should be mentioned that, in the time operating under perishing environment, vibrative system possibility reliability deficiency, and also the cost of system is very high.

-in the system that hole is provided, produce every now and then the scheme of overvoltage.If pressure is enough high, this overvoltage can remove from Kong Chu the frost of blocked hole.The defect of this technology is its cost: this is because it need to use and can temporarily transmit high-power supersize ventilating system.

-use the electronic system for local heat hole, but this application proves very difficult in practice.

Therefore, should be appreciated that, in order to keep the heat exchange of good level in such machine, can will be favourable without stopping or making heating machine in the situation that air blast hole keep unimpeded.

Summary of the invention

As being below shown specifically, the present invention sets about proposing a kind of new technical scheme, this scheme by have good design and size, for example, prevent in the situation that not using mechanical oscillation or heating for the system of the blow gas that distributes (, air) because form at hole place the obstruction that frost causes.

For this reason, the present invention proposes one for passing through to impact the equipment of (air blast) jet cooling food, and this equipment comprises tunnel, and this tunnel comprises:

-for the conveyer of the food in tunnel;

-at least one plate, this at least one plate towards conveyer (above this conveyer and/or below) arrange and be provided with through hole;

-and at least one is for by the device that crosses this through hole and blow cold fluid towards food air blast,

This equipment comprises channel network, this channel network for above top board and/or base plate below the blow gas that distributes, described top board and/or base plate are provided with through hole, all or some passages in described passage are provided with spray-hole or playpipe, into through hole in described plate is guided blow gas in this spray-hole or the playpipe location in channel network, to clean all or some through holes in described through hole simultaneously.

As above understood by reading, thereby frost pile up side blow: this be because, in practice, in this air blast tunnel, frost is deposited in top board top and base plate (be positioned at conveyer below, upwards spray cold air to impact the plate on food bottom surface) below, that is to say, therefore, blow the arrival side (rather than side for blowing jet appearance) of the cold air in the system of occurring in.

For example, although can imagine according to the present invention some holes of cleaning (, hole 80% to 90%), preferably will blow network positions and become likely to clean all through holes.

In equipment of the present invention, the plate that is provided with through hole is advantageously made up of the stainless steel of food-grade.These plates are dismountable, so that it is cleaned after operation.

In food industry, there are various multi-form plates, particularly, these plates can be plane or V-shaped or corrugated.

Purely for schematic object, through hole in plate can also have different forms, and be in particular cylindricality, circle, slit-cut sth. askew alternatively (each through hole distributing along plate or the some slits that distribute in the whole length of plate, each slit almost has the whole width of plate), or band is cut sth. askew or the circular cone of Chamfer Edge.

Common but nonrestrictive, liquid blowing device is the centrifugal blower being driven by motor.

Same, tunnel can make paired plate: top board and base plate, they are positioned at the both sides of conveyer abreast, at least one-preferably whole two-be provided with through hole.

The invention still further relates to a kind ofly for carry out the method for cooling food by the impact jet flow in tunnel, this tunnel comprises:

-for the conveyer of the food in tunnel;

-at least one plate, through hole laid and is provided with by this at least one plate with respect to conveyer, and these one or more plates are positioned at top and/or the below of conveyer;

-and at least one is for by through hole and blow the device of cold fluid towards food,

The method is characterized in that, during all or a part of cycle of operation in tunnel and/or in all of tunnel or during some stoppage in transit cycles, in the following manner all or some through holes are cleaned:

-use channel network that blow gas is distributed in to the top of top board and/or the below of base plate, this top board and/or base plate are provided with through hole, all or some passages are provided with spray-hole or playpipe, and this spray-hole or the playpipe position in this network makes this network likely blow gas be guided into the through hole in one or more plates;

-supply with blow gas to channel network, to clean all or some through holes simultaneously, but preferably clean all through holes.

Accompanying drawing explanation

Accompanying drawing 1 a), b), c) etc. shows one embodiment of the present of invention by schematic partial view with its different views, in the accompanying drawings:

-shock plate is the ripple corrosion resistant plate form that is continuous V-arrangement part, and each V-arrangement part is provided with one emissions groove/hole, cuts sth. askew alternatively in described groove/hole;

-Fig. 1 a) illustrates that the structure of the plate with 7 V-arrangement parts and blowing device, this figure illustrate with resolution model so that read better (right side view of Fig. 1 in a) provides the details of V-arrangement part);

-Fig. 1 b) illustrates plate and the blowing device under assembly mode;

-Fig. 1 c) illustrates the situation that through hole is stopped up by frost;

-and Fig. 1 d) illustrates that compressed air jet arrives the effect in each V-arrangement part, this makes likely to clean each through hole (right side view in this accompanying drawing provides the details of V-arrangement part again);

-Fig. 2 illustrates the alternate embodiment of safeguarding pipe of Fig. 1 with partial schematic view, and each V-arrangement part of shock plate is provided.

The specific embodiment

As at Fig. 1 a) to 1d) in clearly visible, for this embodiment, be provided with at one end maintenance pipe closure, that diameter is about 40mm, this safeguards that pipe extends along the end in plate one side of V-arrangement part, and is provided with and is connected with this maintenance pipe and to spraying compressed-air actuated little injector or pipe (having the internal diameter of about 2-5mm at this) in V-arrangement part towards each V-arrangement part.Therefore, first the air spraying will contact and clean the first hole, be then the second hole, the 3rd hole etc.Therefore, injector has been dredged the some holes that become a line in the distance of about 200-600mm with flow velocity according to the pressure of sprayed air.

In the time that needs spray (as has been shown, no matter this is in the production phase in tunnel or in its stoppage in transit stage, and no matter this is the order of being sent separately by operating personnel or carries out according to the regular time interval of programming in advance, or the instruction of for example sending after the pressure measuring value in ventilation equipment in the information of receiving the blocked state that represents hole based on automatic controller), strength by air-spray is removed the long-pending frost towards each playpipe, separated frost is taken away by air stream, and tunnel can continue normal operation.

Due to design pressure, the injection of blow gas can very short (being generally several seconds, for example, between 0.2 second and 2 seconds).

Can be by making interval between injection enough far make compressed-air actuated consumption optimization in the machine thermal efficiency keeping between injection.

For the quantity of limit compression air ejector, hole is aimed at, and compressed-air actuated injection is arranged so that it clashes into into some holes of a line.

As implied above, for the present embodiment, safeguard that by single pipe is mounted to a side that is positioned at plate, still, obviously can imagine the specifically size according to shock plate uses some maintenance pipes, wherein arranges one in each side of plate, then blows along two relative directions.

Be very rare by needing two larger plates of safeguarding above pipe (each end of plate arranges, and for example arranges in the centre of plate), to such an extent as to be not considered at this.

Fig. 2 shows the partial schematic view of the alternate embodiment of safeguarding pipe of Fig. 1, and each V-arrangement part of shock plate is provided.

Claims

1. for the equipment of cooling food, this equipment is by impact jet flow cooling food and comprise tunnel, and described tunnel comprises:

-for the conveyer of the food in tunnel;

-at least one plate, through hole is laid and be provided with to this plate in the face of described conveyer, and this plate is positioned at top and/or the below of described conveyer; And

-at least one device for crossing through hole and blowing cold fluid towards this food,

This equipment comprises channel network, this channel network is for being provided with above the top board of through hole and/or being provided with the blow gas that distributes below the base plate of through hole, all passages or portion of channel are provided with spray-hole or playpipe, into through hole in described plate is guided blow gas in these spray-holes or the playpipe location in described channel network, to clean all through holes or a part of through hole in these through holes, preferably clean all through holes simultaneously.

2. equipment according to claim 1, is characterized in that, described plate is the form that is the ripple corrosion resistant plate of continuous V-arrangement part, and each V-arrangement part is provided with a round, and this round is cut sth. askew alternatively; This channel network comprises at least one maintenance pipe, and this maintenance pipe is associated with each plate, safeguards an end sealing of pipe and an end that holds V-arrangement part at this; This equipment comprises towards the injector of each V-arrangement part, and this injector connects with this maintenance pipe and to managing in corresponding V-arrangement part and spray blow gas with this maintenance.

3. for the method for cooling food, the method is carried out cooling food by the jet impacting in tunnel, and this tunnel comprises:

-for the conveyer of the food in tunnel;

-at least one plate, through hole is relatively laid and be provided with to this plate and described conveyer, and this plate is positioned at top and/or the below of described conveyer; And

-at least one is for by described through hole and blow the device of cold fluid towards described food,

The method is characterized in that, during all or a part of run duration in tunnel and/or all or a part of stoppage in transit in tunnel, in the following manner all or a part of through hole is cleaned:

-channel network (C) be used in the top of the top board that is provided with through hole and/or be provided with through hole base plate below the blow gas that distributes, all or portion of channel is provided with spray-hole or playpipe, described spray-hole or the playpipe location in this network makes likely blow gas to be guided into the through hole in this plate

-supply with blow gas to described channel network, to clean all or a part of through hole simultaneously, preferably clean all through holes.