Energy-saving method for foam molding

Abstract

The invention relates to an energy-saving method for foam forming, which specifically comprises the following steps of: 1) energy conservation in a heating process: setting a steam pressure difference between a double-sided main heating movable mold and a fixed mold to enable steam to be subjected to directional penetration heating, and performing double-sided main heating after a balanced pressure is reached, so that steam discharge in the penetration heating process is reduced, and an energy-saving effect is achieved; and 2) energy saving in the cooling process: a cooling medium is changed from water to air in the cooling process, and compressed air penetrates through the interior of the product to discharge heat in the product to cool the product, so that the mold is kept at a relatively high temperature, and the energy-saving effect of cooling the product without cooling the mold is achieved. The method has the advantages that the step design is reasonable and reliable, the consumption of penetrating steam in the step 1) is reduced by 50%-100%, the heat loss of the mold / water tank in the step 2) is reduced by 30%-50%, and the forming period in the step 2) is shortened by 20-50 s.

Description

Technical Field

[0001] The invention relates to an energy-saving method for EPP / EPS / EPO foaming molding, and belongs to the technical field of foam product molding. Background Art

[0002] The heat required by the foam product itself during the molding process accounts for less than 1% of the total heat consumption in the molding process. Most of the heat is consumed in the penetration heating process, the double-sided main heating, the heating and temperature rise of the mold and the water tank during the process, and the constant radiation heat dissipation of the steam pipe.

[0003] During the penetration heating stage of foam molding, the steam valve on one side and the drain valve on the other side are opened, and steam enters the mold cavity from the steam valve, passes through the interior of the product to preheat the filled foam particles, and then is discharged from the drain valve on the other side. During the penetration process, the foam particles absorb very little heat, and most of the steam is discharged, resulting in a large amount of loss.

[0004] During the double-sided main heating stage, the steam valves on both sides of the mold are opened at the same time, and the drain valves are closed at the same time, so that the steam pressure in the mold cavity quickly rises to the set value and reaches the particle melting temperature. During the double-sided main heating process, the aluminum alloy mold and the steel water tank have a larger specific heat capacity than the foaming particles filled, and the heating speed is fast, so most of the heat of the double main heating is used to heat the mold and the water tank.

[0005] The cooling process of foamed products is to cool down by spraying cooling water onto the surface of the mold core. Therefore, the cooling water will take away most of the heat of the mold and water tank, resulting in heat waste.

[0006] The following is the steam consumption ratio of each stage of foam molding obtained by analyzing the production data statistically collected by the manufacturer (statistical data, there will be large individual differences due to factors such as molding equipment, molds, process parameters, materials, product structure, pipeline layout, etc.).

[0007]

[0008] Based on the above, combined with the huge usage of EPS and EPP in electronic packaging, cushioning packaging, construction industry, automobile manufacturing and other industries, energy saving in the foaming molding process is very necessary. Summary of the invention

[0009] The purpose of the present invention is to provide an energy-saving method for EPP / EPS / EPO foam molding to solve the problems raised in the above background technology. In order to solve the above technical problems, the technical solution provided by the present invention is: an energy-saving method for foam molding, which specifically includes the following steps:

[0010] 1) Energy saving during the heating process: By setting a certain pressure difference between the fixed mold and the moving mold during the double-sided main heating process, the steam for double-sided main heating first penetrates unidirectionally for preheating and then undergoes double-sided main heating and welding, so as to achieve the energy-saving effect of reducing the discharge of penetrated steam.

[0011] 2) Energy saving during the cooling process: By setting the air-cooling penetration function and separately setting the air-cooling priorities for the fixed mold and the moving mold, compressed air penetrates into the interior of the foamed product to quickly discharge the heat inside the product, separating the cooling of the product from the cooling of the mold, achieving the effect of cooling the product without cooling the mold, reducing the heat loss caused by the repeated heating and cooling of the mold water tank during the heating and cooling process, and achieving the purpose of energy saving and efficiency improvement.

[0012] Preferably, in step 1), a certain pressure difference is set between the fixed mold and the moving mold during the double-sided main heating process to achieve the penetration effect. When the pressure reaches the balance between the male and female molds, it is equivalent to double-sided main heating.

[0013] Preferably, in step 1), priorities are set for the fixed mold and the moving mold during the double-sided main heating. First, one side is heated at a lower pressure, and then the other side is heated at a higher pressure. The penetration function is achieved through the pressure difference during the single-sided heating process.

[0014] Preferably, in step 1), the double-sided main heating is carried out in multiple stages. The penetration function section achieved through the pressure difference precedes the double-sided simultaneous heating section in time.

[0015] Preferably, in step 1), auxiliary exhaust and intake devices are added to the fixed mold and the moving mold during the double-sided main heating. The air inlet and the exhaust port can be respectively connected to the air chambers of the fixed mold and the moving mold to generate a pressure difference between the fixed mold side and the moving mold side, achieving the purpose of steam penetrating the product.

[0016] Preferably, in the forming program of step 1), priorities for heating the fixed mold and the moving mold are added during the double-sided main heating.

[0017] Preferably, in step 2), the cooling medium is air.

[0018] Preferably, in step 2), the cooling method is penetration cooling.

[0019] Preferably, in step 2), the air-cooling penetration function is set in the forming program, that is, the compressed air inlet valve on one side and the exhaust valve on the other side of the forming equipment are opened together, and the compressed air penetrates from the inside of the product to remove heat.

[0020] Preferably, in the forming program of step 2), priorities for air-cooling penetration of the fixed mold and the moving mold are set.

[0021] The advantages of the present invention are as follows:

[0022] 1) Compared with the independent penetration heating method of traditional processes, in the present invention, the steam boosting process of double-sided main heating is first used for penetration heating and then for double-sided main heating, reducing the penetration energy consumption by 50%-100%.

[0023] 2) Compared with the water cooling method of traditional processes, the compressed air through-flow air cooling method adopted in the present invention can reduce the heat loss caused by the repeated heating and cooling of the mold and water tank during the molding process by 30%-50%.

[0024] 3) The compressed air through-flow air cooling method adopted in the present invention can further reduce the energy consumption of penetration heating and double-sided main heating.

[0025] 4) The compressed air through-flow air cooling method adopted in the present invention can shorten the molding cycle of foamed products by 20s-50s. Specific embodiments

[0026] The following uses specific embodiments to illustrate the present invention, which is not a limitation of the present invention.

[0027] Embodiment

[0028] An energy-saving method for foam molding specifically includes the following steps:

[0029] 1) Energy saving in the heating process: By setting a certain pressure difference between the fixed mold and the moving mold in the double-sided main heating process, the steam of the double-sided main heating first performs one-way penetration preheating and then double-sided main heating welding to achieve the energy-saving effect of reducing the discharge of penetration steam;

[0030] 2) Energy saving in the cooling process: By setting the air cooling penetration function and separately setting the priority of through-flow air cooling for the fixed mold and the moving mold, the compressed air penetrates inside the foamed product to quickly discharge the heat inside the product, separating the cooling of the product from the cooling of the mold, achieving the effect of cooling the product without cooling the mold, reducing the heat loss of the repeated heating and cooling of the mold water tank in the heating and cooling process, and achieving the purpose of energy saving and efficiency improvement.

[0031] Preferably, in step 1), a certain pressure difference is set between the fixed mold and the moving mold in the double-sided main heating process to achieve the penetration effect, and when the pressure reaches the balance of the male and female molds, it is equivalent to double-sided main heating.

[0032] Preferably, in step 1), the priority is set for the fixed mold and the moving mold in the double-sided main heating. First, one side is heated at a lower pressure, and then the other side is heated at a higher pressure, and the penetration function is achieved through the pressure difference in the single-sided heating process.

[0033] Preferably, in step 1), the double-sided main heating is set to be carried out in multiple stages, and the penetration function section achieved through the pressure difference precedes the double-sided simultaneous heating section in time.

[0034] Preferably, in step 1), auxiliary air extraction and exhaust devices are added to the fixed mold and the moving mold during double-sided main heating. The air inlet and the exhaust port can be respectively connected to the air chambers of the fixed mold and the moving mold to create a pressure difference between the fixed mold side and the moving mold side, achieving the purpose of steam penetrating the product.

[0035] Preferably, in the forming process of step 1), the heating priorities of the fixed mold and the moving mold are increased during double-sided main heating.

[0036] Preferably, in step 2), the cooling medium is air.

[0037] Preferably, in step 2), the cooling method is through-cooling.

[0038] Preferably, in the forming process of step 2), a function of air-cooling through-penetration is set, that is, the compressed air inlet valve on one side and the exhaust valve on the other side of the forming equipment are opened together, and the compressed air penetrates through the product from the inside to remove heat.

[0039] Preferably, in the forming process of step 2), the priorities of air-cooling through-penetration of the fixed mold and the moving mold are set.

[0040] In the specific implementation of the present invention, by setting the steam pressure difference and priority of double-sided main heating, the foamed product is first preheated by unidirectional penetration, then double-sided heating and welding are carried out, and then by setting the penetration function and priority of air-cooling, the foamed product is cooled down, achieving the purpose of energy saving and efficiency improvement.

[0041] Now, taking the forming process of an EPP packaging box and the energy-saving method of the present invention as an example.

[0042] Heating energy-saving method 1: By setting the steam pressure difference of double-sided main heating, the foamed product is first preheated by unidirectional penetration, and then double-sided heating and welding are carried out.

[0043] As shown below

[0044]

[0045]

[0046]

[0047] Heating energy-saving method 2: By setting the steam pressure difference and priority of double-sided main heating, the foamed product is first preheated by unidirectional penetration, and then double-sided heating and welding are carried out.

[0048] As shown below

[0049]

[0050] Cooling energy-saving method: By setting the penetration function and priority of air-cooling, the foamed product is cooled down.

[0051] The following shows

[0052]

[0053]

[0054] There is a certain error in time, and the compressed air pressure cannot be freely set. The time setting standard is that the product temperature drops to about 40 - 55°C). The following shows

[0055]

[0056] As described above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An energy-saving method for foam molding, characterized in that, Specifically, it includes the following steps: 1) Energy saving during the heating process: By setting a certain pressure difference between the fixed mold and the moving mold in the double-sided main heating process, the steam for double-sided main heating first undergoes one-way penetration preheating and then double-sided main heating and welding, so as to achieve the energy-saving effect of reducing the discharge of penetrated steam; 2) Energy saving during the cooling process: By setting the air-cooling penetration function and respectively setting the air-cooling penetration priorities of the fixed mold and the moving mold, compressed air penetrates into the interior of the foamed product to quickly discharge the heat inside the product, separating the cooling of the product from the cooling of the mold, which can achieve the effect of cooling the product without cooling the mold, reducing the heat loss of repeated heating and cooling of the mold water tank during the heating and cooling process, and achieving the purpose of energy saving and efficiency improvement.

2. The energy-saving method for foam molding according to claim 1, characterized in that: In step 1), a certain pressure difference is set between the fixed mold and the moving mold in the double-sided main heating process to achieve the penetration effect. When the pressure reaches the balance of the male and female molds, it is equivalent to double-sided main heating.

3. An energy-saving method for foam molding according to claim 1, characterized in that: In step 1), priorities are set for the fixed mold and the moving mold in the double-sided main heating. First, one side is heated at a lower pressure, and then the other side is heated at a higher pressure. The penetration function is achieved through the pressure difference in the single-sided heating process.

4. The energy-saving method for foam molding according to claim 1, characterized in that: In step 1), the double-sided main heating is set to be carried out in multiple stages, and the penetration function section achieved through the pressure difference precedes the double-sided simultaneous heating section in time.

5. A method for energy saving in foam molding according to claim 1, characterized in that: In step 1), auxiliary exhaust and intake devices are added to the fixed mold and the moving mold in the double-sided main heating. The air inlet and the exhaust port can be respectively connected to the air chambers of the fixed mold and the moving mold to generate a pressure difference between the fixed mold side and the moving mold side, achieving the purpose of steam penetrating the product.

6. The energy-saving method for foam molding according to claim 3, wherein: In the forming program of step 1), the heating priorities of the fixed mold and the moving mold are increased in the double-sided main heating.

7. An energy-saving method for foam molding according to claim 1, characterized in that: In step 2), the cooling medium is air.

8. An energy-saving method for foam molding according to claim 1, characterized in that: In step 2), the cooling method is penetration cooling.

9. An energy-saving method for foam molding according to claim 6, characterized in that: In step 2), the air-cooling penetration function is set in the forming program, that is, the compressed air inlet valve on one side and the exhaust valve on the other side of the forming equipment are opened together, and the compressed air penetrates from the inside of the product to remove heat.

10. An energy-saving method for foam molding according to claim 6, characterized in that: In step 2), the air-cooling penetration priorities of the fixed mold and the moving mold are set in the forming program.

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