Abstract:Rumen pH is an important physiological indicator for the health of cows in modern dairy farming.Among the existing electrodes, the intermittent pH reference electrode uses gas pressurization to promote the electrolyte exudation. However, there is a risk that the electrolyte outflow may be blocked. Hyperelastic metal was used to design a valve to control the intermittent outflow of reference electrolyte and a reference electrolyte pressurization component-based on a spring piston system.The final assembly of the intermittent rumen pH detection probe in dairy cows was completed. The finite element analysis of the valve component determined that the length of the hyperelastic metal rod in the valve component was 9 mm, and the distance between the central axis of the silicone tube and the fixed end of the nitinol rod was 4.5 mm. The pressure component used a spring with a piston for pressure, the spring stiffness was 0.284 N/mm, the free height was 70 mm, and the maximum compression was 49 mm. The finite element analysis of the valve components showed that the maximum stress of the hyperelastic metal rod was 281 MPa, which was within the hyperelastic range and can be recycled. Performance experiments showed that the probe can work stably with the pH error no more than 0.1. According to the life test, the probe can be used 60 480 times. When the measurement period was set to be 20 min, the probe can meet the service life of two years. In the rumen environment test, the average absolute deviation between manual measurement and system measurement was 0.11, and the maximum absolute deviation was 0.25. The research result can provide technical means and reference for the development of rumen pH monitoring equipment.