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4.4 Work cycle description
The LDPU, whose functional element is the "B series lobe displacement pump", is equipped with a control unit that, depending on the version, can be
fi tted with a speed controller, a gear motor, an electric motor, a pneumatic motor or a hydraulic motor, with or without electric panel.
The capacity adjustment is achieved by increasing or decreasing the number of revolutions of the "B series lobe displacement pump", intervening directly
on the revolutions output of the motor mentioned above or acting on the actuators on the control panel (inverter), if fi tted.
The LDPU is reversible: full performance can be achieved in both rotation directions of the pump rotors (section 1.3.5 lists the types of rotors used).
The pumping action of the "B series lobe displacement pump" is achieved thanks to the counter-rotation of two rotors (letter "C" indicated in the fi gure in
section 1.2, indicating one of the two rotors), housed inside the pumping chamber (letter "U" indicated in the fi gure in section 1.2 or see fi gure below). The
rotors are assembled on rotating shafts supported by bearings (letters "G" and "H" shown in the fi gure in section 1.2), which are housed in the external
gearbox (letter "S" shown in the fi gure in section 1.2). Via a couple of sprocket wheels (letters "N" and "P" indicated in the fi gure in section 1.2) one
transfers motion from a drive shaft (letter "M" indicated in the fi gure in section 1.2) to a driven shaft (letter "R" indicated in the fi gure in section 1.2). The
synchronism of the rotors is such that they rotate without coming into contact with each other: in this conditions "the rotors are in phase".
When the lobes of the rotors move away from each other, the volume between them increases, creating a decrease in pressure near the suction outlet:
this enables a certain volume of fl uid to enter (value of fl uid transported identifi ed in the table in section 1.3.1, in the "theoretical capacity" column, de-
pending on the pump model size) into the pumping body. The fl uid is transported along the internal of the pumping chamber, from the suction inlet to
the delivery outlet of the pump body. When the volume of fl uid, trapped between the lobes and the external perimeter of the pumping chamber, reaches
in proximity of the delivery outlet, the counter-rotation of the two rotors creates a sudden decrease of available volume and a consequent increase in
pressure that pushes the fl uid out of the pumping body, by channelling it into the plant where the LDPU is installed.
4.5 Cycle start instructions
The start of the LDPU work cycle is supervised and activated by the operator in charge of running the plant, after having carried out the following preli-
minary checks.
4.5.1 Preliminary operations: check list
Before commissioning the "B series lobe displacement Pump Unit" check the following:
•
if the LDPU has suffered damages, contact the O.M.A.C. s.r.l. Technical Offi ce immediately as described in chapter 2;
•
make sure that all the bolted connections are tightened properly and that the installation of the LDPU has been carried out properly in accor-
dance with the requirements of this use and maintenance manual;
•
ensure continuity of the equipotential protection circuit and that it is connected, as per section 3.5.1.1 of this use and maintenance manual;
•
ensure that all hydraulic connections, where required by the confi guration of the LDPU, are carried out properly, as described in chapter 3;
•
make sure, as a preventive measure, that there is lubricant oil, visible via the oil level cap placed on the side of the pump gear box, part of the
LDPU: please bear in mind that all pumps fi tted in the LDPU are already supplied with the proper amount of lubricant oil.
DANGER
Incorrect lubrication or lubrication with lubricant products incompatible with the materials used in the construction and completion of the LDPU can lead
to premature wear or breakage of the sealing elements or other parts in contact with the process fl uid.
ATTENTION
O.M.A.C. s.r.l. is not liable for any damage caused by improper use of lubricants incompatible with the materials used in the construction and completion
of LDPU or with the process fl uid:
•
ensure that the power supply voltage of the LDPU is that required as shown on the electric motor data plate or electric panel; it is reminded that
the electric connection must be carried out by skilled personnel and compliant with the electric motor data plate, both for the connection of the terminal
board and for the thermal calibration in accordance with the maximum admitted absorption;
•
ensure that the pipes have been washed with clean water, to remove foreign bodies, cinders, dust or scraps from processes carried out on
the plant;
•
with reference to chapter 3 ensure that a CIP/SIP cleaning and/or sanitisation cycle has been carried out, as per section 3.4;
•
if there is a mechanical safety valve on the front cover or a bridge one on the external cover of the LDPU, check that the spring has been
adjusted, as indicated in section 3.3.3;
•
if there is a pneumatic safety valve on the front cover of the LDPU, check that the auxiliary pneumatic unit pressure has been adjusted, as
indicated in section 3.3.3;
•
make sure that all gates in suction and delivery are completely open, in order to ensure the suction pipes are full of process fl uid;
ATTENTION
The LDPU must not be used to process fl uids other than that / those for which it has been selected and sold, with reference to the intended use. If in doubt,
contact the O.M.A.C. s.r.l. Technical Offi ce. Fluids incompatible with the materials used in the construction and completion of the LDPU can damage the
same Unit, other parts of the unit and cause injuries and damages to the operators in charge of running the plant.
4
Chap.4 - pag.
Via Giovanni Falcone, 8
42048 Rubiera (RE) - Italy
E-mail:info@omacpompe.com SitoWeb:www.omacpompe.com
O.M.A.C. s.r.l.
Tel.0522/629371 - 629923 Fax 0522/628980
Rev.4 del 01/2011 O.M.A.C. s.r.l.
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