What Is Brass Foot Valve? – Importance, Functions, Replacing 黄铜底阀是什么？—— 作用、重要性、更换方法

一、What is a Brass Foot Valve 什么是黄铜底阀

二、Core Functions 主要功能

1. Keep pump primed 维持水泵引水（保压存水） When the pump stops working, the foot valve closes tightly to retain water inside the suction pipeline, so you don’t need to refill water to prime the pump every time you restart it. 水泵停机时，底阀自动密封关闭，将水保留在吸水管内，再次开机时无需反复手动加水引水。
2. Prevent water backflow 防止水倒流 Avoid pipeline drainage and air lock failure caused by reverse water flow. 避免因水体倒流导致管道放空、气堵故障。
3. Filter impurities 过滤杂质 The built-in strainer blocks sediment, sand, branches and dirt, protecting the pump impeller from abrasion and clogging. 内置过滤网可以拦截泥沙、树枝、杂物，保护水泵叶轮不被磨损、堵塞。
4. Stable water supply pressure 稳定供水压力 Ensure continuous and steady water intake to guarantee stable water output and working pressure of the pump. 保证持续稳定进水，让水泵出水流量、工作压力保持平稳。

三、Importance 重要性

1. Effectively extend the service life of water pumps, avoid dry running damage caused by frequent pump priming. 有效延长水泵使用寿命，避免反复引水造成水泵空转烧坏。
2. Brass material has strong corrosion resistance, wear resistance and sealing performance, far more durable than plastic foot valves. 黄铜材质耐腐蚀、耐磨、密封性好，使用寿命远优于塑料底阀。
3. Reduce frequent maintenance work and save electricity and labor costs. 减少频繁检修，节约电费与人工维护成本。
4. Widely used in shallow well pumps, centrifugal pumps, farm irrigation, domestic water supply and industrial water circulation systems. 广泛应用于浅井泵、离心泵、农田灌溉、家用供水、工业水循环系统中。

四、Signs You Need to Replace the Brass Foot Valve 底阀需要更换的故障现象

1. The pump loses prime easily after shutdown, must add water repeatedly to start. 水泵停机后很容易失水掉压，每次启动都要重新加水。
2. Water outlet flow is small, water pressure unstable, pump frequently starts and stops. 出水流量偏小、水压不稳，水泵频繁启停。
3. Abnormal noise during pump operation, or obvious water leakage inside the pipeline. 水泵运行异响，管道内部出现明显渗水泄压。
4. The strainer is severely blocked, the internal spring and sealing gasket are aging, rusted or damaged. 过滤网严重堵塞，内部弹簧、密封垫片老化生锈、破损失效。
5. Brass valve body cracks or serious corrosion. 黄铜阀体开裂、严重锈蚀。

五、Step-by-Step Replacement Steps 详细更换步骤

1. Cut off the pump power supply, close all control valves and drain residual pressure and water in pipelines. 切断水泵电源，关闭控制阀门，排空管道内余压与积水。
2. Lift out the suction pipeline from the well or water tank to expose the old foot valve. 将吸水管从水井 / 水箱中提拉出来，露出老旧底阀。
3. Unscrew the old foot valve, clean dirt and rust on the pipe threads. 拧下旧底阀，清理管道螺纹处的污渍、铁锈。
4. Wrap PTFE sealing tape clockwise around the male thread of the new brass foot valve to prevent water leakage. 在新黄铜底阀外螺纹处顺时针缠绕生料带，做好防漏水密封。
5. Screw on the new foot valve moderately, do not over-tighten to avoid thread cracking. 适度拧紧新底阀，切勿用力过猛造成螺纹崩裂滑丝。
6. Confirm the strainer faces downward to filter impurities normally. 确认过滤网朝下安装，保证正常过滤杂质。
7. Put the pipeline back into water, prime the pump and test startup, check whether there is water leakage and normal water supply. 将管道放回水中，给水泵引水试运行，检查有无漏水、出水是否正常。

六、Precautions 注意事项

1. Select the foot valve with matching thread specification (NPT/BSP) and pipe diameter. 选择和管道管径、螺纹规格（英制 / 美制）匹配的底阀。
2. Keep the foot valve a certain distance away from the sludge at the bottom of the water source to prevent rapid clogging. 底阀要和水源底部淤泥保持一定距离，防止快速堵塞。
3. For drinking domestic water, choose lead-free brass foot valves to meet drinking water safety standards. 生活饮用水场景，请选用无铅黄铜底阀，符合饮水安全要求。