Plastic mold with water chiller(2)
2. Ice water temperature difference
Plastic mold cooling fluid (ice water) temperature is generally subject to processing data and the shape of the finished product and the onset of a greater change, such as polystyrene thin-walled beaker, mold request ice water temperature below 0℃;However, in most cases, the temperature of the cold water requested by the mold is above 5℃, the microcomputer is fully functional cold water machine to provide above 5℃ cold water, low temperature intelligent temperature control cold water machine satisfied with the request of below 5℃ and below 0℃. The temperature difference of the ice water at the inlet and outlet of the plastic mold is usually set according to the requirements of the finished product. In many cases, the temperature difference of 3-5℃ is the most ideal, but sometimes the temperature difference of 1-2℃ is also required. The smaller the temperature difference, the greater the flow of ice water, and the smaller the flow. For example: when the temperature difference is 5℃, the flow needs 60l, and when the temperature difference is 2℃, the flow needs 150l.
3. Ice water flow
The amount of ice water flowing through a plastic mold is directly related to the amount of heat the mold takes and the temperature difference between the ice water flowing in and out of the mold. For example: to remove 6480kcal/h of heat from the mold, if the temperature difference is 3℃, what is the minimum flow rate required?The ice-water flow q=6480÷3÷60=36 (l/min).
4. Theory of water quality of ice water
In the process of using water chiller, water softening is also a problem that can not be ignored. The ph value of the water also needs to be constantly observed, the best ph value should be equal to 7, greater than 7 ph value will attack a terrible corrosion scene, such as not to adopt measures, will be in the evaporator, mold endogenous scale, will play the role of heat insulation, severe, make its energy conversion effect reduce 30%. This obviously requires thinking about softening hard water. The most effective way to do this would be to equip the system with an electronic hard water softener, which is planned to be built on an ac principle. It can be equipped with different standard softeners according to different flow rates, which can be directly connected in the circulating water pipeline. Generally, it will not cost too much to be equipped with water treatment softener, and it can also participate in certain amount of scale remover in the circulation system at a certain period.
5. Flow and pressure of ice water machine
General injection mold cooling, ice water pressure select 0.1-0.2mpa, can be satisfied with the request, and the microcomputer full function cold water function satisfied with this request, when the pressure request is higher than 0.2mpa, need to plan separately, in order to select the corresponding pressure from the pump to meet the needs of the system water supply.
6. Cooling of hydraulic oil and drum feeding section
General hydraulic oil and cylinder feeding section to choose cooling water tower water to cool, because this is not only the best way, the cost of production alone, is also very economical, unless there is a specific request for its temperature, water can be used to cool it.
7. Insulation of ice water pipes
Ice water pipes must be insulated, as insulation not only prevents severe loss of cooling capacity, but also prevents dewdrops from forming on the outside walls of the pipes. For example, the temperature of ice water is 10℃, the ambient temperature is 30℃, a 25 meter long, the external product is 25m2 of metal pipe thermal radiation can reach 750kcal/h, which is almost 3hp compressor cooling capacity of 10%, 5hp compressor cooling capacity of 6%. The connection between the chiller and the plastic mold is usually made of reinforced rubber hose. As such rubber hose itself has the function of heat insulation, but the length is more than 5m, we should also consider the moderate heat preservation and insulation.