B Series Ldpu Optional Features; Pump Unit With Pneumatic Safety Valve On Cover; Pump Unit With External Mechanical Bridge Safety Valve; Motorized B Series Ldpu On Fi Xed Base - OMAC B Series Operation And Maintenance Manual

1.11.5 Pump with pneumatic safety valve on cover
One of the possible versions of the "B series lobe displacement pump" envisions the possi-
bility to fi t a pneumatic safety valve on the front cover, which intercepts and dampens any
pressure peaks over the limit for which the valve is set. The valve is fi tted on the cover and
is made up of a cylindrical casing in which a piston slides. The fl uid pressure (FP) acts on
the piston face, whilst the pressure of the pneumatic plant (PP) acts on a plate fi xed to the
piston.
When the force that the air exercises on the plate is higher than that exercised by the li-
quid on the piston, the valves stays closed, otherwise the piston moves opening discharge
volumes in the pumping chamber, that enable pressure balancing. Calibrating the by-pass
means supplying the air chamber with a pressure value that keeps the valve closed until the
pressure limit value in the pump reaches the desired value.
1.11.6 Pump with external mechanical bridge safety valve
The external safety valve is made up of a spring valve positioned on a pipe bridge that
connects delivery and suction and can also be used as a by-pass to recycle all or part of the
pumped liquid. On this valve, the adjustment of the tightness pressure is up to a spring that
can be more or less compressed. The system composed in this manner is one-way so if one
inverts the direction of the pump, it is essential to invert the positioning of the valve as well
that, in any case, must always be on the delivery side.
One can choose various kinds of springs according to the working pressure. The adjustment
must be carried out manually on site
on the appropriate adjustment ring.

1.12 B Series LDPU optional features

1.12.1 Motorized B Series LDPU on fi xed base
For customer needs, the motorised LDPU can be assembled on a base made of AISI 304 or
metal, to then be fi xed, via bolts, to the fl oor.
The motorised LDPU on a fi xed base is made up as follows:
• Support base made of press-moulded sheet metal;
• B series lobe displacement pump fi xed to the base;
• Speed controller / gear motor / direct electric motor / hydraulic motor / pneumatic
motor fi xed to the base;
• Flexible mechanical transmission coupling;
• Flexible mechanical transmission coupling protection;
• Seals protections (excluding the fl ushed mechanical or double mechanical
seals);
• Fairing (when envisioned in the pump Unit supply, in this special version the
mechanical transmission coupling protection is not installed).

1.12.2 Motorized B Series LDPU on trolley base

For customer needs, the motorised LDPU can be assembled on a base made of AISI 304 or
metal, equipped with polyamide
or pneumatic wheels and trolley transportation handle.
The motorised LDPU on a trolley base is made up as follows:
• Trolley for unit transportation;
• B series lobe displacement pump fi xed to the trolley;
• Speed controller / gear motor / direct electric motor / hydraulic motor / pneumatic
motor fi xed to the base.
• Flexible mechanical transmission coupling;
• Flexible mechanical transmission coupling protection;
• Seals protections (excluding the fl ushed mechanical or double mechanical
seals);
• Fairing (when envisioned in the pump Unit supply, in this special version the
mechanical transmission coupling protection is not installed);
• Electric control panel (not present in the version shown in the fi gure).
18
Chap.1 - pag.
Via Giovanni Falcone, 8 42048 Rubiera (RE) - Italy
E-mail:info@omacpompe.com SitoWeb:www.omacpompe.com
FP
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.
PP
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