FR2480792A1 - Cleaning grills for bread baking ovens - by soaking successively in alkaline and neutralising soln., rinsing and drying before coating with silicone - Google Patents

Abstract

A process and an installation for cleaning metal grills used in bread prodn. bakeries, esp. stainless steel honeycombed grills for rotary ovens which require thorough descaling every two years or so. The new process replaces sand blast cleaning which distorts and erodes the grills. The process includes (1) soaking the grills in a bath of a soln. comprising 100 ems. potassium hydroxide per litre water. (2) The grills are transferred to a second bath of a soln comprising 30 ems. sulphuric acid per liter of water. (3) The grills are rinsed with high pressure spray jets of demineralised water at 110 deg. (4) The rinsed grills are dried pref. with hot air, and sprayed with a silicone.

Description

 @@ a present invention relates to the cleaning of grids used for baking in bakeries.

At present, bakers are increasingly equipping themselves with so-called "rotary" ovens.

That is to say that instead of placing the dough pieces on the fixed bottom of the oven, they place them on honeycomb grids, most often in stainless steel, placed on a trolley which itself enters the oven.

 These grids, which are very enduring (20 years), clog up after one to two years.

Currently the only known process is sandblasting and ejection of sand under pressure.

But this method is not really effective because it deforms the grids considerably, moreover cleaning is imperfect.

The method of cleaning the grids according to the invention makes it possible to avoid these drawbacks, while being entirely harmless despite the use of chemicals.

This cleaning process uses two tanks containing solutions at given concentrations.

For the first, it is water and potash, heated with gas.

The second is water and sulfuric acid.

The grids will be successively immersed in the first then in the second tank. Then they will be washed under a jet of water at a given temperature and pressure, so as to remove any chemical trace remaining on the grids.

Dried with hot air, they will be during the last phase, knitted, which constitutes a kind of coating preventing the dough from sticking to the grid.

-According to a first variant: the chemical action consists in first using a solution of water and potash, which pickles, then a solution of water and sulfuric acid, to neutralize the potas (very little) remaining on the grid then a rinsing with boiling water for a given pressure of fifty kilos in order to eliminate all traces of sulfuric acid, thus ensuring non-toxicity of this process.

 -According to a second variant: the mechanical action dries the grids without deforming them.

according to a third variant: silicone coating constituting a protective film of the cellular grids.

The cleaning process according to the invention therefore makes it possible to ensure perfect pickling, without toxicity or deformation of the plates and a protective coating.

 The accompanying drawings are those of the two tanks.

As it is don @ represented, the process according to the invention allows or rather involves the passage of the grids in a first tank (diagram I) of capacity 1600 liters and containing:
- water H @ O
- KOH potash in the following proportions: 10% KOH, i.e. I00 grams of potash for I000 cm3 or I liter of water.

-in a second tank with capacity 1600 liters and containing
- HLO water
- sulfuric acid
H2SO4 to neutralize "all" the potash contained in the first tank it would be necessary:
H2SO4 + 2 KOH # K2SO4 + 2
98 112
x 100
x = 98x100 = 87.5 grs.

112
It would therefore take 87.5 grams to neutralize 10,000 grams of potash per liter of water.

But since there will be very little potash on the grids, using a dilution of 30 grs of sulfuric acid per 1000 cm @ of water will be enough to neutralize the remaining potash.

At the end of the last phase of the chemical operation, a jet of water demineralized at IIOO and at a pressure of 50 kilos, will eliminate the remaining sulfuric acid, this being very eager for water will therefore be conveyed by it , thus ridding the grid of all chemical traces.

 @ Last phase: Drying and siliconing: 9n will pass the grids in front of a hot air turbine and the dried grids will be siliconed with silicone C.A.F 70004 Special non-toxic food product.

The cleaning process which is the subject of the invention will be able to be used specifically for cleaning the honeycomb grids used for bread-making in bakeries.

Claims (1)

Claims d: The process for cleaning the grids is characterized by the fact that it includes passing it through a first soda with ION and then a second bath of sulfuric acid (30 grs per 1000 cm @ of water Then the grids will be rinsed with a jet of hot water at high pressure, before being dried and then silicone-coated (silicoae  70004) last phase of this cleaning process. 2: Device for implementing the method according to claim  4, characterized in that it comprises: -Two stainless steel tanks 2 meters side by 0.80m  high, used for baths. -A lavojet developing a pressure of 50 kilos ~ From a hot air gun  ~ A pistol and compressor for siliconization. 3: cleaning method according to claim t characterized in that  chemical bodies (KOH, \ Si) are used which pickle.  4: cleaning method according to claim t characterized in that the last chemical possibly remaining on the grids will be eliminated by the boiling water jet for a pressure of 50 X Ilos, therefore no toxicity of the grids, no degradation, or deformation. 5: cleaning method according to claim t characterized in  that the grids will be dried without being deformed. 6: cleaning method according to claim o characterized by  silicone coating ensuring a protective film on the honeycomb grids.