Pump station Pedrollo HF JDWm

Principle of operation

The JDW series includes centrifugal type self-priming electric pumps used for pumping water from deep wells. The self-priming effect is achieved through the use of a venturi placed inside the ejector assembly, which is mounted on the pump or, more often, lowered into the well and connected to the pump housing by two pipes. Only a part of the total feed generated by the closed centrifugal impeller is sent to the discharge pipe; the remaining water (called start-up water) is recirculated through the Venturi system, which, when connected to the suction chamber, creates a vacuum in it, which is necessary to suck water from the place where the ejector unit is immersed. The water pumped out of the opening of the ejector block is mixed in the Venturi diffuser with the recirculated water from the pump, as a result of which its pressure is increased by the recirculated water, and is sent to the pump through the suction pipeline. When the ejector block is mounted directly on the pump casing, the JDW series pumps operate in the same way as the JSW series pumps.

Scope and installation

Pumps of this series are recommended for pumping clean water and chemically non-aggressive liquids. JDW series pumps. when installed above ground with a submerged ejector unit, ensure reliable operation even when the water level in the well is 45 meters below the level of the installation of the pump itself.
Due to their reliability, ease of use and economy, these pumps can be successfully used in everyday life, in particular for the automatic supply of water from small and medium-sized filling tanks, for irrigating gardens, etc., that is, in all cases where the suction depth exceeds normal limits (9 meters).
Installation of a check valve on the opening of the ejector block is mandatory. It is recommended to install a valve on the pump discharge to ensure adequate pressure balancing during operation. Before starting the pump, fill the pipeline connecting the pump housing with the ejector unit with water. When pumping water from a depth not exceeding 9 meters, the ejector unit (only 4" ejector) can be installed directly inside the pump housing. In this case, before the first start-up, fill the pump with water, filling the suction pipe is not required.
The pump must be installed indoors or protected from the weather.

Structural features

• Pump body made of cast iron, equipped with suction and discharge ports with gas UNI 338 pipe thread.
• Cast iron ejector assembly.
• Impeller radial, centrifugal type (on request in technopolymer).
• AISI 316 stainless steel drive shaft (AISI 416 up to 0.75 kW).
• Mechanical seal made of ceramic and graphite.
• Electric motor: the pumps are driven by a PEDROLLO asynchronous electric motor of closed type, with external ventilation, suitable for continuous operation. Insulation class F (B up to 0.75 kW.)
• Single-phase motors have a built-in thermal protection device (emergency switch). Three-phase motors must be equipped with an appropriate external emergency switch, connected in accordance with current regulations.
• Degree of protection IP 44.
• Design and safety regulations in accordance with EN60 335-1 (IEC 335-1, CEI 61-50) IEC 34
• The characteristics of the curves in the table have tolerances according to ISO 2548.