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HPP ET Serie Instrucciones Para El Ensamblaje Y Mantenimiento página 32

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  • ESPAÑOL, página 61
For the main dimensions, refer to Fig. 4.
The Manufacturer's After-Sales Service is at the disposal of Skilled Technicians to provide all related information:
• to identify the most suitable application and its correct execution;
• as regards the precautions to be adopted in the event of continuous operation being required;
• as regards particularly heavy-duty use.
The pump applications must, in any case, be performed according to the best rules of mechanical engineering.
For the hydraulic suction, delivery and bypass connections, refer to Fig. 7, which represents a generic diagram of a
possible pump installation.
CAUTION
• The main plant errors to be avoided are indicated in bold type.
CAUTION
• The temperature of the water supply is a crucial factor for the life and performance of the pump.
To use water at temperatures above 40 °C/104 °F, follow the instructions in the following paragraph "Operation
at a temperature above max value".
• During suction, the pump must be fitted with an adequately sized filter.
The filtering system must have the following characteristics:
- filtering power between 100-320 microns;
- filter capacity three times greater than max pump flow rate;
- diameters of filter inlet and outlet mouths the same or greater than those of pump suction.
• During pump suction, avoid blockages, counterslopes and overturned U curves. Make sure the system is such as
to prevent emptying the suction pipes when the pump is stopped (also see Fig. 7).
• The suction and delivery pipes must not convey excessive forces or torques to the pump.
• The suction pipes must have an inner diameter the same or greater than that of pump suction, a nominal pressure
of 10 bar/145 psi and must be strong enough to prevent any crushing caused by any suction vacuum.
• The suction pipes must have a nominal pressure of not less than the maximum pressure of the pump.
• To cushion vibrations and irregular flow, we recommend to fit:
- a pressure accumulator (or a flexible delivery hose at least 1.5 m/5 ft long) between the pump delivery coupling
and the pressure unloader/regulation valve;
- a flexible delivery hose at least 1.5 m/5 ft long downstream of the pressure unloader/regulation valve;
- a flexible suction hose at least 1.5 m/5 ft long upstream of the pump suction connection.
• In case of supply by means of a centrifugal pump, prepare the system so that:
- the centrifugal pump has a flow rate at least double that of the positive-displacement pump;
- centrifugal pump operation is separate from that of the positive-displacement pump;
- the start of the centrifugal pump always precedes that of the positive-displacement pump;
- a pressure switch is fitted on the suction line downstream of the filter to protect the positive-displacement
pump from any lack of water due to filter blockage;
- a pressure gauge is fitted to monitor the supply pressure close to the centrifugal pump.
Suction and delivery connections are available both on the right and left sides of the head.
CAUTION
• To use water at a temperature above max value (for short periods only and in any case within the limit of
60 °C/140 °F), follow these installation rules:
- supply the piston pump with a centrifugal pump having double the flow rate and a max pressure of 3 bar/43.5 psi;
- if the centrifugal pump is not used, reduce the rotation speed to 500 RPM;
- always be careful to comply with the direction of rotation.
For applications at temperatures above 60 °C/140 °F, contact the Manufacturer's After-Sales service.
32
HYDRAULIC CONNECTION
OPERATION AT A TEMPERATURE ABOVE MAX VALUE

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