## 4 PdM Structure Development Methodology
### Get Data
#### 4.1.1 Equipment and Critical Parts Selection  
The hospital industry, like other industries, uses mechanical equipment and these differnet types of equipment serve the whole community. The selection of the equipment relates to its importance in the industry.  
For this study, we investigated one amongst the most critical hospital mechanical machinery. An autoclave sterilizer is mandatory in hospital with the aim of avoiding the possibility of pathogen transmission from the medical object to patient or to hospital staff and environmental contamination. This machine uses a saturated steam to produce high temperature and pressure as sterilization agent. Sterilization serves to destroy pathogenic microorganism that could lead to infection [82; 83; 84].  
Some authors [60; 85; 86] focused on sterilization chamber regulation and steam quality, but did not consider the main mechanical parts to generate the required agent for successful sterilization. This machine is structurally complex; consequently, its maintenance is stressful and it requires reserving their spare parts in stock in order to avoid any kind of its component failure that may lead to breakdown its operation.  
Among its critical parts, there is a steam generator that is made up by water tank and heaters in order to generate a saturated steam, which is the main agent of sterilization. Once one of the heaters slows down, the sterilization is affected. There are also pumps that are devices that move fluids by mechanical force. Pumps are also extensively used for small to large scale appliances in both domestic, enterprise, organization, and manufacturing industry appliances [62; 63].  
Figure 2: Methodological steps to construct a Predictive Maintenance (PdM) Structure using Internet of Things (IoT).  
Pumps worse behaviors may cause the most amount of failure not only of itself, but of the whole critical system. For the autoclave, pumps occupy considerable importance in its normal working process, as any kind of defect could cause a total downtime of the whole system, which may result in expensive complications.  
Autoclave presents two centrifuge pumps, namely water and vacuum pumps with the same mechanical and physical parameters. Water pumps serve to supply water to the steam generator, whereas vacuum pumps are used in order to evacuate air bulbs and moisture on the load in sterilization chamber to continually keep the effective vacuum condition for successful sterilization.  
Pumping system contains different components, such as a pump itself, which feeds kinetic energy to fluid, a motor that supplies the mechanical force to pump for its working, piping, valves, measuring equipment, and beneficiary equipment. Any stress from one of these components results in pump behavior change, which is then transferred to the coupled motor.  
Referring to literature, different researches put emphasis on the fault diagnosis of the pumps by analyzing changes in its associated motor quantities [49; 51; 59; 64; 65; 66; 67; 71; 72], but did not consider the pumps as an individual unit that borrows stresses from its own inefficient operation or surrounded components.  
The first pumps defects symptoms, such as bearing failure, misalignment, bed failure, and associated motor failure, which lead to a rise in their operating temperature [63; 69], which, in turn, gradually shortens its life cycle and efficiency. In normal condition, pumps keep their environment temperature and, for any change in temperature increase, the inner temperature is directly propagated to its metallic housing and then to a coupled motor.  
The data gathering and processing experiment of this study focus on steam generator and pumps temperature as main physical behavior for detectin failure. The collected data were used in constructing a predictive model that can learn the real time data taken with a small interval of time and classifying the components' health status.