Why is pump monitoring reasonable in a thermal oil system?

Pumps are the determining components in heat transfer systems with liquid heat transfer mediums.
As „heart“ of the system, they ensure that the heat transfer medium circulates in the system and the thermal energy provided by the heater is conveyed to the right position in the system.

These pumps can be equipped with relatively simple monitoring sensors that bear no relation to the purchasing costs of a new pump. Even a damage on a component of a pump, e.g. a damaged bearing, can be repaired if detected early; otherwise at a later stage, most pumps must completely be replaced. The economic loss because of an unwanted standstill due to damage to the pump or even a fire caused by a leaking pump, more than ever exceeds the costs for a reliable pump monitoring.

When is pump monitoring reasonable?

Monitoring is always reasonable. Pump monitoring is an important factor in the field of system safety, and it is very easy to implement, also as a retrofitting kit.
Because of the reduced risk, this safety device pays off already from the first day of purchase.

Redundantly designed pump stations provide operating safety in case the main pump fails. However, in case of fire or explosion on the pump station, the redundant pump can be damaged directly or indirectly, and redundancy will not be provided anymore. As a direct damage, for instance, a damage of the cabling can be seen, which is often led over the same cable duct together with the main pump.

Finally, in the sense of operating safety, pump monitoring should always be used.

Which criterions should be considered for monitoring of the pumps?

Beside the standardised inspection of the pump, there are three parameters that should permanently be checked during the operation of the pumps. These parameters include bearing temperature, pump vibration, and leakages of the pump. These should absolutely be part of the monitoring program.

How is pump monitoring integrated in the system?

The necessary sensor circuits are mounted on the pumps and integrated in the already existing system control. The limit values for alarms and switching off are then to be set in the control system depending on the operating environment and the pump used.

What does the NESS Pump Monitoring System do?

The NESS Pump Monitoring System consists of three modules with which it measures the most important parameters – leakage (NESS NPCL), pump vibration (NESS NPCV) and bearing temperature (NESS NPCT) – during the operation of the pump. The NESS Pump monitoring system is part of the NESSessities concept which constantly increases safety, availability, durability and efficiency in thermal oil systems.

How do I integrate the NESS Pump Monitoring in my system?

No problem at all! Like all NESSessities, also the NESS Pump Monitoring System is designed with practical orientation. The modules can be used independently from the manufacturer and are integrated in existing system control. This concept allows the relatively easy retrofitting also for already existing systems.

Which and how many sensors must be integrated?

All-in-all 4 sensors must be integrated for monitoring. The leakage monitoring (NPCL) is a small stainless-steel container that is mounted on the base plate of the pump. Filling level and temperature are measured on this container to be able to distinguish between cold and hot filling up (pumps can have a normal leakage due to operation). The vibration monitoring (NPCV) consists of 1-2 sensors that are mounted on motor housing / or pump (depending on the design of the coupling and the maintenance strategy). The bearing temperature (NPTC) is mounted on the bearing carrier of the pump.

Is it necessary to monitor all three parameters, or can I decide on single solutions?

Because it is a modular system, it is possible to use leakage, pump vibration, or bearing temperature as a single monitoring solution. For safety-related points of view however, we recommend the complete monitoring of the parameters.

Which technical characteristics does the leakage monitoring have (NPCV)?

Mechanical ConnectionsPrecision steel pipe Ø8 x 1 with Ermeto screwed connection G¼“
DimensionApprox. 130 x 156 x 180mm (without fastening parts and screwed connection
Container capacity0.3 litres
MaterialStainless steel
VoltageV = 24 V DC
CurrentI ≤ 0.2 A

It is connected by precisions steel pipes with Ermeto screwed connection. These are included in the scope of delivery as mounting set in two different variants (depending on type of pump and the local conditions).

Which technical characteristics does the vibration monitoring have (NPCV)?

Measuring range0 – 12 mm/s ± 10%
Frequency range10 Hz to 1 kHz ± 5% – ISO10816
InsulationSensor basis insulated
Housing materialStainless steel
Sensor element/designPiezoresistive / compression
Tightening torque8 Nm
Weightapprox. 150g
Current output4 – 20 mA DC; 2-core connection

It is mounted to the pump by a threaded part that is included in the scope of delivery as mounting set depending on the type of pump.