Particularly challenging issues when designing and manufacturing industrial gas valves and regulators (precisely medical oxygen regulator), are gas-dynamic pressure surges and adiabatic compression phenomena, along with the design and optimisation of the complex geometries of valves. Depending on the field of application, the pressure surges can lead to considerable malfunctions and, in very critical cases, to total failure of the respective component.To develop an efficient numerical methodology for the simulation of flow through industrial valves with different configurations/geometries, the computational approach is related to the mesh free smoothed particle hydrodynamic (SPH) method, but the present method introduces a mesh for the efficient calculation of the pressure gradient, and laminar and turbulent diffusion. In addition, the mesh is used to remesh (reorganise uniformly) the particles to ensure a regular particle distribution and thus, a good convergence of the method. An implicit interface algorithm for remeshed particle-mesh method simulation of multiphase flows with large density ratios is to be developed, here the particles are marked via a smooth step function, which assume the continuity of the pressure and density between the two flows, consequently overcome the discontinuity of the pressure/density gradient over the interfaces which may cause computational instabilities.The result will be a better understanding of the high pressure surges and adiabatic compression phenomena in complex geometry of valves and a better prediction of the transient pressure- and the temperature-gradients. Hence we achieve an optimised, safer and more precise medical pressure regulator protecting the sensitive components from damage or destruction by gas-dynamic pressure surges in the future.