Control method for ice-phase and water-phase seawater freshing machine for fishing boats

Abstract

The invention discloses a control method for an ice-phase and water-phase seawater freshing machine for fishing boats. The control method is used for providing the ice-phase and water-phase seawater for freshing by directly utilizing natural seawater and adapting to temperature changes of the freezing point of the seawater. The control method includes the steps: firstly, temperature Tym of discharging water of an evaporator is set; secondly, when actual temperature TLj of the discharging water of the evaporator reaches Tym, current pressure difference delta Pym of feeding water and the discharging water of the evaporator is acquired, and targeted pressure difference delta Pm of the feeding water and the discharging water is calculated according to the equation of delta Pm = delta Pym (1+xi); thirdly, when actual pressure difference delta Py of the evaporator is equal to delta Pm, if TLj is larger than 0 DEG C, targeted temperature TLm of the discharging water of the evaporator is reserved to be equal to 0 DEG C, and if TLj is not larger than 0 DEG C, TLm is reserved to be equal to TLj; and fourthly, when TLj is equal to TLm, if delta Py is larger than delta Pm (1+xi), TLm is reserved to be equal to TLj + 0.5 DEG C, and if TLm is larger than 0 DEG C, TLm is reserved to be equal to 0 DEG C.

Description

technical field [0001] The invention relates to the technical field of freezing and preservation, in particular to a control method of an ice-water two-phase seawater preservation machine for fishing boats. Background technique [0002] For a long time, fishing boats have generally adopted the method of icing their catches to keep them fresh. However, with the adjustment of fishing boats’ operation methods, fishing grounds have moved outside, resulting in longer fishing voyages and longer fishing operations. In addition, consumers have higher and higher requirements for fish products. , the traditional fresh-keeping method with ice has the defects of uneven temperature (leading to less than 50% of the first-class seafood rate, and 20% of aquatic products are inedible) and short fresh-keeping time (generally about 7 to 10 days) , has become less and less suitable for the existing fresh-keeping requirements of fishery production. [0003] In order to overcome the above-mentio...

AI Technical Summary

Problems solved by technology

[0002] For a long time, fishing boats have generally adopted the method of icing their catches to keep them fresh. However, with the adjustment of fishing boats’ operation methods, fishing grounds have moved outside, resulting in longer fishing voyages and longer fishing operations. In addition, consumers have higher and higher requirements for fish products. , the traditional fresh-keeping method with ice has the defects of uneven temperature (leading to less than 50% of the first-class seafood rate, and 20% of aquatic products are inedible) and short fresh-keeping time (generally about 7 to 10 days) , has become less and less suitable for the existing fresh-keeping requirements of fishery production

[0003] In order to overcome the above-mentioned defects, there is currently a fresh-keeping machine, which adopts the principle of air-conditioning and refrigeration, and mainly includes a compressor, a condenser, a throttle valve and an evaporator in structure. The water flows through the evaporator and is cooled by the evaporator. In this way, the water is continuously circulated, and the temperature of the water can be controlled within a certain range. However, the control method adopted by the fresh-keeping machine can hardly make the The fresh-keeping machine directly uses natural seawater to keep fresh. This is because the physical process of seawater freezing is relatively complicated. Factors such as different regions, different temperatures, different times, different seasons, and different depths will affect its freezing point. The change of seawater freezing point is related to seawater. There is a close relationship between salinity and density