The shape memory alloy thermostatic shower head with three functions balances water pressure and maintains constant temperature despite fluctuating water pressure. Its core function relies on the temperature-sensing and deformation properties of the shape memory alloy, combined with the dynamic adjustment logic of the valve core. When water pressure fluctuates (such as a sudden drop in water pressure during peak household usage or a sudden increase in pressure on a single water supply), the mixing ratio of hot and cold water can be disrupted. Increased water pressure can cause a sudden increase in the flow rate of one water line (for example, the hot water line), while decreased water pressure can cause a decrease in the flow rate of another line, leading to temperature fluctuations. In response, the shape memory alloy, leveraging its phase change properties (reverting to a fixed shape or deforming when the temperature changes), instantly senses these slight changes in water temperature. This deformation drives the valve core to adjust the opening of the hot and cold water lines, bringing the mixing ratio back within the set range. This adjustment process simultaneously adapts to flow fluctuations caused by water pressure fluctuations, achieving a balanced "water pressure changes while water temperature remains constant" effect.
The valve core's dual-stage adjustment structure and the shape memory alloy work together to effectively mitigate the impact of water pressure shocks on constant temperature. The valve core of a shape memory alloy thermostatic shower head with three functions is typically divided into a "water pressure adaptation layer" and a "temperature regulation layer." The shape memory alloy primarily functions in the temperature regulation layer, while the pressure adaptation layer absorbs the impact of water pressure fluctuations through elastic components (such as silicone diaphragms and microsprings). When water pressure suddenly increases, the elastic component of the pressure adaptation layer compresses first, limiting the instantaneous increase in the flow rate of both hot and cold water, thus preventing drastic temperature fluctuations caused by sudden flow changes. Simultaneously, the shape memory alloy senses the water temperature fluctuations and slowly adjusts the valve core opening of the temperature regulation layer to further stabilize the mixing ratio. This two-stage "buffer first, then adjust" logic prevents water pressure shocks from directly transmitting to the temperature regulation stage while also ensuring smoother regulation by the shape memory alloy, preventing thermostatic failure caused by sudden water pressure fluctuations.
The water flow channel design for the three-function shower head utilizes the adjustable properties of the shape memory alloy to adapt to varying water pressure requirements, preventing pressure fluctuations during mode switching from affecting thermostatic control. The shape memory alloy thermostatic shower head with three functions (such as shower, spray, and pulse modes) features different flow channel diameters and outlet densities, corresponding to different water pressure requirements. For example, pulse mode requires higher water pressure for a punchy effect, while spray mode requires lower water pressure to maintain a fine atomization. Therefore, the channel design matches each mode with a unique "water pressure-flow" adaptation range. The temperature adjustment threshold of the shape memory alloy is also fine-tuned with each mode switch: When switching to high-pressure mode, the deformation sensitivity of the shape memory alloy increases appropriately to quickly respond to possible water temperature fluctuations under high pressure. When switching to low-pressure mode, the shape memory alloy increases the adjustment range to ensure sufficient mixing of hot and cold water under low pressure. This synergistic adaptation of the mode and the shape memory alloy ensures stable temperature control even when water pressure fluctuates within the appropriate range for each mode.
For low-pressure scenarios (such as persistently low water pressure), the shape memory alloy balances insufficient water pressure with the required constant temperature through "small opening precision adjustment." When water pressure is too low, the total flow rate of hot and cold water decreases. If the valve core is opened too wide, insufficient pressure in one water line (such as the cold water) may prevent adequate flow, resulting in a high water temperature. If the opening is too narrow, the total flow rate is insufficient, affecting the shower experience. In this situation, the memory alloy slightly deforms the valve core to adjust the valve core to a "small but balanced" state. This ensures that the hot and cold water mix according to the set ratio, while also increasing the local water flow rate through the narrow opening, compensating for the flow rate shortfall caused by insufficient water pressure. Furthermore, in low-pressure mode, the water flow channel utilizes a "reduced diameter, increased flow" design (i.e., reducing the channel diameter to increase water pressure). This, combined with the memory alloy's narrow opening adjustment, maintains the required shower flow while maintaining a constant temperature, avoiding the problem of "cold water and weak flow" under low pressure.
In high-pressure scenarios (such as sudden increases in water pressure), the memory alloy incorporates a "current limiting protection" mechanism to prevent overheating, balancing high pressure with constant temperature. If the hot water line pressure is too high under high pressure, the hot water flow rate can far exceed the cold water flow, causing the water temperature to rise sharply. At this point, the memory alloy senses a rise in water temperature and deforms, pushing the valve core toward the cold water path, increasing the cold water flow rate and decreasing the hot water flow rate. Simultaneously, the valve core's flow-restricting structure (such as the stepped sealing ring) limits the maximum hot water flow rate to prevent excessive hot water influx. Furthermore, in high-pressure mode, the outlet channel incorporates a diversion channel to divert some of the high-pressure water flow to non-main outlet areas (such as the auxiliary spray holes). This reduces the hydraulic pressure load on the main channel and minimizes the impact of water pressure on the hot and cold water mixing ratio. This allows the memory alloy's regulation to focus more on temperature stability rather than combating excessive water pressure shocks.
The compatible design of the memory alloy and the sealing assembly prevents water pressure fluctuations from causing leakage that could affect thermostat accuracy. Fluctuations in water pressure can easily create tiny gaps in the seal between the valve core and the housing due to pressure shocks. Leakage can lead to an imbalance in the hot and cold water mix, affecting the memory alloy's regulation. Therefore, the Shape Memory Alloy Thermostatic Shower Head with Three Functions utilizes sealing materials with excellent elasticity and weather resistance (such as fluororubber and food-grade silicone). The seal is aligned with the deformation trajectory of the memory alloy. As the memory alloy drives the valve core to deform, the seal moves synchronously with the valve core, maintaining a tight fit and preventing leaks due to changes in water pressure. Furthermore, the seal's cross-section is designed to adapt to the compression requirements under varying water pressures. At high pressures, the seal compresses more, enhancing the seal; at low pressures, it compresses less, preventing excessive compression that could affect the valve core's adjustable flexibility.This ensures that the sealing effect does not interfere with the memory alloy's constant temperature regulation.
The coordinated calibration mechanism of the entire system ensures that the memory alloy, valve core, and water flow channel form a unified adjustment logic as water pressure fluctuates, ensuring a consistent temperature and shower experience. Before leaving the factory, the Shape Memory Alloy thermostatic shower head with three functions simulates different water pressure scenarios (such as pressure fluctuations from 0.1MPa to 1MPa) to calibrate the deformation threshold of the memory alloy and the adjustment range of the valve core. This ensures consistent response speed and adjustment direction to changes in water pressure. Furthermore, a "water pressure-temperature" adaptation curve is set for each of the three function modes, ensuring that channel changes during mode switching are synchronized with the memory alloy adjustments.
During use, the memory alloy slightly adjusts its phase change sensitivity based on long-term temperature sensing data to adapt to long-term fluctuations in household water pressure (such as a gradual drop in water pressure due to aging pipes). This synergistic mechanism, from factory calibration to long-term adaptation, enables the Shape Memory Alloy thermostatic shower head with three functions to stabilize water temperature while maintaining the normal user experience in the three function modes, even when water pressure fluctuates continuously or momentarily, achieving a dynamic balance between water pressure and constant temperature.
