Microtherm machines the temperature control of equipment

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Summary low temperature machines section volume to be 250mm of × of 300mm × 300mm, temperature of treatment area center is in - 30 ～ inside 40 ℃ limits, use R502 to undertake as refrigeration agent vapour compresses type loop refrigeration, monitor through temperature, built lukewarm accuse to machine an area field of three-dimensional temperature interface, can satisfy what treatment facilities machines area to microtherm to need water. Label of document of TB65 of date of classification of the graph in equipment of refrigeration of control of temperature of area of treatment of keyword low temperature piles up B normally machine treatment facilities works below normal temperature, do not need to control the treatment area temperature that machines equipment. But the development as new material, new processing technique, the treatment of a few material shapes need the inferior temperature in deviate room temperature, it is ultralow temperature condition even next undertaking, for example certain live thing, medical the treatment of material shapes need undertakes inside limits of 0 a few Celsius. The material of special to these having requirement undertakes machining, installation must be designed on treatment facilities lukewarm control additional device, use a requirement in order to make sure the temperature amplitude inside treatment area, uniformity and stability are accorded with. The crucial part of microtherm treatment area is the end on area of refrigeration equipment, right refrigeration dose, treatment sealed protective screen and lukewarm charge the relevant unit such as module. What the treatment area that needs to control temperature is 250mm of × of 300mm × 300mm is hexahedral, be similar to the freezer compartment of freezer. Lukewarm accuse those who machine area to safeguard for double deck structure, lining is plating zine plate, outer the bag has adiabatic insulation material. 3 establish face and underside interlining traditional Chinese clothes to have evaporator. Next exterior 160mm that process a work of most advanced distance. Structure of this equipment machinery is shown 1 times like the graph, to save a space, workbench is designed " a few " word, one aspect of the matter is fixed go up in 2 axes slide block, one aspect of the matter bypasses freezer compartment rear wall extends interior. Its carry movable mould piece basically includes component of switch of guide screw of driver of electric machinery, electric machinery, slideway, spacing and join to wait, according to numerical control the instruction implements campaign. Main movement form includes: 1.

Z axis electric machinery drives workbench to carry out a pace to enter litre fall motion; 2.

Electric machinery of axis of X, Y drives shower nozzle to implement planar scanning campaign; 3.

The athletic positive pole that uses spacing switch to realize 3 movement rod is restricted, signal of negative limit, origin is collected. Refrigeration system includes compressor, condenser, evaporator to reach lukewarm accuse implement, the control equipment such as relay. The refrigeration means of this refrigeration equipment compresses type refrigeration to circulate for vapour, namely from evaporator (refrigeratory) the dry saturated vapour that come out by inspiratory compressor, the course compresses the overheat steam that makes high temperature high pressure, enter condenser to undertake next constant pressure and radiative to saturated liquid, repass throttle step-down drops in temperature to wet vapour condition, wet vapour of microtherm low pressure enters evaporator to undertake absorption of heat, vaporization makes dry saturated steam finally, such go round and round, the refrigeration that finish circulates (graph 2) . Nextpage circulates every time in the quantity of heat that the refrigeration agent of unit quality absorbs is: Q=h1 - H4 (1) criterion the Q of total quantity of heat that agent of unit time refrigeration absorbs is: Q=m(h1 - H4)(2) refrigeration coefficient (refrigeration efficiency) . For: Vapour of the H1 in type, H2, H4 compresses the enthalpy that the different node in refrigeration loop process is in to be worth, KJ/kgM -- the mass flow of refrigeration agent, kg/s refrigeration agent chooses R502, it is by quality per cent 48.

The R22 of 8 ％ and 51.

The R115 of 2 ％ is comprised. When only course compresses type refrigeration, its evaporate temperature lowest can be amounted to - 55 ℃ left and right sides, can satisfy - the demand that 30 ～ have working inside limits of 40 ℃ temperature. The refrigeration capacity that leaves R502 in inferior temperature is made an appointment with than R22 big 13% . With R22 the graph that press frit is refrigerating capacity of exemple estimation R502. Set Te= - 42 ℃ , when the inlet temperature of compressor refrigeration agent is 10 ℃ , h1=420kJ/kg, when Tc=40 ℃ , expand the super-cooling temperature TRc=40 before a powerful person ℃ , h4=245kJ/kg, criterion the refrigerating capacity Qe=175kJ/kg of R22, the refrigerating capacity of R502, qe ≈ 198 KJ/kg, criterion the 198kJ of × of Q=m of total refrigerating capacity of R502. Lukewarm accusing module is the main component in this component. Of refrigeration equipment start with stopping is support treatment area place measures temperature (T is measured) , the refrigeration temperature of the setting (T is set) and allow T 0 of fluctuant temperature △ (general requirement is more than 2.

0 ℃ ) of collective decision, control process is as follows: When T measures ＜ T to set ＋ △ T 0, red light is bright, begin refrigeration; T is measured CNC Milling