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Regarding the storage conditions and methods of plate heat exchangers:
1. Store in a room with a temperature of 15~20℃ and a maximum humidity of 70%.
2. There are no ozone-generating equipment indoors, such as electrodes and welding equipment. Ozone will cause rubber to crack. Plate heat exchangers are strictly prohibited to use plate heat exchangers as the negative electrode of electric welding to prevent arcs from piercing the plates.
3. Organic solvents and acid solutions cannot be stored indoors, and heat radiation and ultraviolet radiation should be avoided.
4. Drain the medium in the equipment.
5. After storage for more than 6 months, the clamping size of the plate bundle should be relaxed to 1.1L, and then clamped to L when the plate heat exchanger manufacturer uses it.
6. The surface of the clamping bolts should be painted with better anti-rust paint.
There are several thermal resistances in series in the heat transfer process of the plate heat exchanger, so the heat exchanger is a multi-capacity object with relatively large time constant and hysteresis.
According to process requirements, the parameter that needs to be controlled is the outlet temperature of the cold fluid after being heated, and this temperature must be maintained at a certain set value. The main disturbance factors that affect the outlet temperature are: the inlet temperature and flow rate of the cold fluid, and the temperature and flow rate of the heating medium population. There are two common control schemes:
Control the flow of heating medium. This is achieved by changing the heating medium flow rate, that is, the heating medium flow rate is used as the manipulated variable to control. When deviating from the set temperature. The controller sends out corresponding control information, changes the valve opening, and controls the flow of the heating medium, so that it meets the process requirements. Due to the simple structure of this scheme, it is widely used in factories.
However, for a heat exchanger, its heat transfer area is certain. When the flow of the heating medium is large enough and the heat exchange reaches a saturated state, the effect of increasing the flow to increase the outlet temperature is not great.
