Analytical presets for new temperature control components

On the contrary, if the temperature drops, the adjustment cylinder is also closed, and the whole process controls the opening degree of the adjustment sleeve according to the temperature change of the mixed fluid, and finally achieves the purpose of linearly adjusting the flow rate of the cold fluid <4>.

The control principle usually uses a temperature sensing element to control the solenoid valve to regulate the outlet flow. This traditional method has many inconveniences in actual use <5>. For each valve of the selected temperature range, a different adjustment spring can be used to change the temperature control range, the characteristics of which can be described by a curve. (a) is the temperature-expansion pressure characteristic curve of the temperature sensing medium, (b) is the correspondence between the output force of the temperature sensing medium and the opening height (a) temperature medium temperature D expansion pressure characteristic (b) temperature medium output force and opening The height of the correspondence relationship performance curve relationship.

Another function of the spring set is to reset. In order to ensure the rapid return of the outer drum of the adjusting cylinder at the initial temperature and the rapid return of the temperature, a certain pre-tightening force is required, which is realized by the spring group. After the temperature control valve is opened, the temperature sensing medium is in an expanded state. When the temperature is lowered, the temperature sensing medium is in a contracted state, but the valve stem and the adjusting cylinder cannot be automatically reset, and the spring group must be forced to return to the position.

The design idea is that the expansion force generated by the temperature sensing medium is large, so the bearing load of the spring is large, and the size is limited by the installation conditions, so that the parallel cylindrical spiral compression combined spring can be used. The double-layer combined spring side-by-side combined compression spring can be further divided into an isometric deformation side-by-side combined compression spring and an unequal deformation side-by-side combined compression spring <7>.

Therefore, to satisfy the above three requirements, it is necessary to make the winding ratios of the inner and outer springs equal, and the value is C=GKKP Hb. In order to prevent the inner and outer two-layer springs from contacting each other during operation and for easy assembly, a certain radial clearance e should be left between the inner and outer two-layer springs. It can be seen that e=(Dw-Dn)-(dw+dn)2 Usually take e=dw-dn2. The unequal deformation side-by-side combined compression springs are assembled and the combined springs are deformed by the constituent springs.

For designing a temperature control valve spring group with a temperature control range determined, first determine four parameters: maximum load, minimum load, spring working stroke, and outer spring diameter. The minimum load is the preload of the spring, and the maximum load is the expansion output force of the temperature sensitive medium corresponding to the upper temperature limit, which can be calculated according to the curve. The spring working stroke is the opening and closing stroke of the adjusting cylinder. The outer diameter of the outer spring is limited by the size of the valve port. Calculate <8> with these four parameters and then according to the literature combined spring design calculation method.

In order to facilitate the design and manufacture of the temperature control valve spring group, the free heights of the constituent springs should be equal, so that the compression springs are combined in parallel deformation. When the temperature of the hot and cold fluid entering the valve changes, the temperature of the fluid at the outlet changes accordingly, so that the expansion force of the temperature sensing medium changes, so as to continuously adjust the opening of the adjusting cylinder, which will cause the spring group to continue. Vibration, so the choice of spring material should consider its fatigue resistance.

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