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EN – SAFETY INSTRUCTIONS IN ACCORDANCE WITH DIRECTIVE 2014/34/EU - J-OT-ST ATEX
9. MECHANICAL SEAL
The mechanical seal may be damaged and the liquid in the pump leaks; the user must evaluate this event and adopt the necessary
precautions so that the liquid does not interact with the external environment.
CAUTION Inspect the seal every time the pump is serviced and stop it immediately in the presence of a leak. The
leaking seal must be replaced by following the instructions provided in the pump "User and maintenance
instructions" manual. Varisco original spare parts must be
The mechanical seal must be lubricated with a liquid - compatible with the pumped liquid - which will be contained in the special
tank supplied with the pump. In case of compatibility, we recommend using engine oil SAE 10W-40. A branch is interposed
between the lubricant liquid container and the seal holder for a temperature probe to be connected: in other words, the pump is
set up to detect the temperature of the seal.
The user is responsible for:
- connecting the temperature probe, if this is required based on the risk assessment of the integrator/installer, to a
temperature measuring instrument certified in accordance with directive 2014/34/EU (the instrument is excluded from the
Varisco supply);
- check that the lubricant liquid tank is always full and top up, if required. Fig. 1 shows a diagram of the seal lubrication circuit
and of the application of the heat-sensitive element.
10. SAFETY DEVICE AT THE SYSTEM DELIVERY
It is strictly essential to install a pressure limiting device downstream of the pump: it must be placed as close as possible to the
pump delivery but in any case before any valve that may limit the flow. This component must be compliant with directive
2014/68/EU (PED Directive) in category IV as a safety device and with Directive 2014/34/EU.
CAUTION The requirements concerning safety and protection against the risk of pump explosion are invalidated if
the pressure limiting safety device is missing or its characteristics do not
The operating pressure of this device must be such as to prevent the pump from operating with the delivery closed and in any case
within the operating range permitted. It is recommended to calibrate the device at a pressure 2÷5% higher than the operating
pressure. The operating pressure of this device must be obtained from the pump performance curve regarding the actual rotation
speed.
CAUTION Incorrect calibration of the pressure limiting device invalidates the requirements concerning safety and
protection against the risk of pump explosion.
11. COMPATIBILITY BETWEEN THE PROCESSED LIQUID AND PUMP MATERIALS
The user must always pump liquids that are compatible with the construction materials of the pump. In this regard, chemical
compatibility between the process fluid and the materials of the pump must be verified. Tables that indicate the degree of
compatibility between two materials are readily available in technical literature: from "not recommended" (i.e. alteration of the
characteristics of one of the two materials) to "excellent" (i.e. there are no significant alterations to the characteristics of one of
the two materials). The materials with which a pump is built are selected when ordering: in case of doubt, contact Varisco S.r.l..
The material of the oil seal ring fitted on the rear seal that contains the lubricating liquid is always in PTFE (Teflon®).
CAUTION Use of the pump with pumped fluids that are not compatible with its components is prohibited.
Use of the pump in environments with fluids not compatible with its components is prohibited .
12. ROLLING BEARINGS
The pumps can be built with three types of rolling bearings:
1. shielded or sealed bearings (type 2RS or ZZ) that do not require greasing. Therefore, if used correctly, they do not require
maintenance operations during the expected lifespan of the bearing. For pumps of the JP range which use this type of
bearings, a replacement is required every 1500 hours of operation;
2. bearings which must be lubricated every 500 hours of operation with lithium grease based on mineral oil NILS HTF EP 3
(class NLGI 3) or equivalent;
3. oil lubricated bearings. The oil contained in the support must not drop below the level set by the manufacturer. In order to
prevent abnormal bearing overheating and/or breakage, the pump is fitted with one of the following preventive measures:
- a level switch is mounted on the support and must be connected to a control panel that interrupts the power supply to the
pump drive system when the oil level drops below the set level;
- a temperature sensor is applied to the support to detect the surface temperature at the most stressed bearing. The sensor
must be connected to a control panel which cuts the power supply to the pump drive system when the temperature exceeds
the values shown in Tab. 4.
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SAFETY INSTRUCTIONS IN ACCORDANCE WITH DIRECTIVE 2014/34/EU - J-OT-ST ATEX
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