# Identification of the Wear Margin of a Pipeline-Machine Subsystem
## 7 Conclusions  
The practical use of a new concept for the identification of maintained technical items has been demonstrated. Based on subsystems of fluid transport, it has been shown that the following objectives can be achieved:  
* Determining desired characteristic measurement values of subsystems and decomposing these characteristics and their values into desired measurement values of subsystem functional unit characteristics;
* Determining substitute measures as well as symptom measures of functional unit wear margin;* Identifying the relationships between the substitute measure and symptom measure of a functional unit wear margin, as well as identifying and the relationship between the subsystem wear margin measure and substitute/symptom measure of functional unit wear margin.  
Two subsystems of fluid transport, independent of fluid type, have been distinguished: an open pipeline-machine subsystem and a pipeline-machine subsystem with a closed vessel at the end of the discharge pipe.  
It has been demonstrated that wear margin of an open pipeline-machine subsystem is not exhausted if the subsystem delivers fluid to the destination under the following conditions: under the following conditions:  
* With capacity \(\dot{V}\) falling within the range of \([\dot{V}_{2},\dot{V}_{2}-\Delta\dot{V}_{2}]\), at pressure \(p\) in the range of \([p_{2},\;p_{2}-\Delta p_{2}]\) and temperature \(T\) in the range of \([T_{2},T_{2}-\Delta T_{2}]\);
* With efficiency values in the range \([\eta_{\text{nom}},\;\eta_{\text{nom}}-\Delta\eta]\);
* With failure frequency rate not exceeding a limit value;
* With an acceptable value of availability.  
Using the hydrodynamic model and the thermodynamic model of an open pipeline-machine subsystem, methods of subsystem energy efficiency measurement and subsystem machine efficiency identification have been sorted out. These considerations involve symptom measures and substitute measures of subsystem functional unit wear margin, as well as relationships between the measures and methods for the identification of functional unit energy efficiency. It has been shown that, for pumps, the thermodynamic method allows us to measure the energy efficiency of the pump working chamber.  
In the case of a pipeline-machine subsystem with a closed vessel at the end of the discharge pipe, it has been found that it is not possible to use the method of identification that is used for open pipeline-machine subsystems. Specific measures are proposed for the assessment of the subsystem wear margin: capacity of vessel filling, efficiency of filling the vessel and efficiency of a subsystem filling a pressure vessel. Methods of determining the capacity of vessel filling, efficiency of filling the vessel and efficiency of a subsystem filling a pressure vessel have been developed, based on thermodynamic relationships. Practical reality and plausibility of the proposed methodology have been confirmed experimentally. The wear margin of a pipeline-machine subsystem with a closed vessel at the end of the discharge pipe is not exhausted if the values of capacity of vessel filling, efficiency of a subsystem filling a pressure vessel or efficiency of filling the vessel do not exceed a limit value.  
This research received no external funding.  
The author declares no conflict of interest.