Pulsation damper (SEMI)
When operating compressed air driven double diaphragm pumps (positive displacement pumps), a pulsating delivery flow results from the oscillating movement of the diaphragm. In order to achieve an almost uniform delivery flow, the use of a suitable active pulsation damper is mandatory.
The Dellmeco F range is a specially developed pump with integrated pulsation damper and two separate product chambers. The first product chamber is used for delivering a liquid from a reservoir to the system. This chamber works by using a directly installed and actively controlled pulsation damper. The product flow is thus delivered evenly. An air pressure of at least 1 bar is required for perfect use of the pulsation damper.
The second chamber is used for returning the excess product (e.g. colour, glue, adhesive, etc.) from the system to the reservoir. The second chamber can also be used for circulating the product in the reservoir. The quick sedimentation of a product can thereby be prevented.
When using Dellmeco pumps with plastic housing, the pulsation damper is screwed directly onto the material outlet without the use of further components. When using pumps with metallic housing, the pulsation damper is installed downstream from the pump. Each pulsation damper has a separate compressed air connection. Pumps and pulsation dampers should be connected to the compressed air supply together so that both units are supplied with the same air pressure. As soon as the pump is supplied with air pressure and begins delivery, the pulsation also begins reducing the pulsation. The diaphragm in the pulsation damper, as in the double diaphragm pumps, serves as a separating membrane between the air side and the product side. If the air pressure is reduced or increased as a result of modified operating conditions, the pressure on the delivery side is also reduced or increased. This occurs both in the pump and in the pulsation damper. Consistently good damping of the pulsation is achieved, caused by this automatic adjustment of the pressure. Use in potentially explosive areas (EX II 2GD TX) is assured through the use of conductive polyethylene as the housing material.
Diaphragm monitoring
A moisture sensor (capacitive) is installed in the pump’s silencer. This sensor detects any liquid which inevitably gets into the pump motor in the event of a diaphragm rupture. The sensor’s output signal can be transmitted to an available programmable memory controller or an optionally available control unit.
If the sensor transmits an alarm signal, this alarm can be transmitted to a likewise optionally available solenoid valve. The solenoid valve shuts of the air supply. The pump stops.
Note: If the pump is operated with an upstream moisture separator (filter regulator), damp compressed air can lead to triggering of the sensor (alarm). It is therefore mandatory to install an optionally available moisture separator (filter regulator) before the pump. If diaphragm monitoring (DM1, DM2) is used in a potentially explosive area, an intrinsically safe isolating amplifier should also be provided in addition to the proximity sensor.
Diaphragm monitoring is available in the following models: DM 1 – Moisture sensor, capacitive (Namur) with approx. 3.0 m connection cable DM 2 – Moisture sensor, capacitive (Namur) with control unit
