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Idiomas disponibles
DEFINITION
MEP-A is a series of safety valves for presses and pneumatically acting
safety subject groups; they are 3 way/2 pos. NC active components for
compressed air powered single acting actuators control.
To achieve their safety duties according to effective standars, such as EN
692 for CE contries, these valves must be redoundant (double-body) and
equipped with a dynamic failure monitoring device.
They now spread in four models from nominal size 10 to 40, all with BG
approval.
CONSTRUCTION
Function:
3/2 NC
Construction type:
poppet
Pilot system:
electropneumatic internally feeded
Fluid:
filtered and lubricated air
Materials:
body aluminium
gaskets polyurethan and NBR
Connectors:
with varistors
TECHNICAL SPECIFICATIONS
Nominal
size
Model
A
313MEP-A-50
10
1/2"
314MEP-A-50
15
1/2"
314MEP-A-52
20
3/4"
316MEP-A-50
30
1"
318MEP-A-50
Side
40
1
1
318MEP-A-70
Rear
VALVE CYCLE
(See page 13)
STAND BY (A)
The electropilots (1-2) are deenergized, the cores (3-4) pressed by the spring
close the inlets (5-6) and exhaust the pilot chambers (9-10).
The valve elements (13-14) are kept in the upper position by the springs (21-
22) and by air pressure, closing by the gaskets (15-16) the flow of incoming
air to outlet A.
Outlet A is connected to exhaust R.
OPERATION (B)
Energizing both the electropilots (1-2) the cores (3-4) press the springs
closing the exhausts (7-8) and opening the inlets (5-6).
The air pressure which was charged on 5-6 in the stand by position flows to
the piston chambers (9-10) shifting downword the valve elements (13-14)
connecting the inlet pressure P to the outlet A through passage 23-24 and
closing the exhaust path (11-12).
(Dimensions: see page 14)
Connections
Working pressure
P
R
min
bar
3/8"
1"
2
1/2"
1"
2
1/2"
1"
2
3/4"
1
1
/
"
2
2
/
"
1"
2"
2,5
2
ACCOMPLISHMENT
MEP-A are redoundant double-body, parallel flow pneumatically actuated
valves, rated to limit, in case of malfunction, the residual pressure to values
under 3% of the inlet pressure.
Their inherent dynamic monitoring system blocks valve operation safety in case
an inner leakage occurs, also if very low and not detectable by usual position
sensors.
A phase difference between the two bodies of a few tenth of a second causes
the self locking of the valve, which cannot be inserted back untill the safe
running in the rest position will be restored (delivery sealed and parallel
exhaust of both bodies).
Reset is automatic when the normal function is restored in the stand by
position.
An ancillary monitoring system with manual reset can be actuated by two
pressure switches, delivered as an option, mounted on the relevant
connections.
Mounting position:
Temperature range:
Monitoring circuit:
Manual reset:
Passage
Operations Mass
max
P-A
A-R
no./1'
bar
mm
2
mm
2
8
19
176
200
8
25
176
180
8
40
320
180
8
62
500
160
8
205
1200
140
FAILURE (C)
For instance if one solenoid only (2) is deenergized.
The deenergized pilot (4) closes the inlet (6) and connect the piston chamber
(9) to the exhaust (8).
The valve element (13) is pressed upword by the spring (21) and by inlet
pressure P. The shutter (15) is closed and the path (11) open.
The valve element (14) is on the contrary open.
Pressure at the outlet A is exhausted through the path (11) which, thanks to
its wider section can bear without slowdown also the flow which is coming
from P through the open valve elements (14).
Pressure on channel 6, detectable on connection CP, is exhausted, in a few tenth
of seconds, by R through 18; after this time a new energizing of the pilot (2)
gives no reaction as its internal pneumatic energy is cut. The valve is shut down.
A new operation cycle can be performed again only after restoring the stand by
position of both valve elements so that the inlet pressure can refill channels 5-6.
4
vertical pilots upwards
-10 °C +50 °C
inherent, dynamic
a reset circuit, according to EN 692
standard, can be achieved by means of
two optional pressure switches.
Power consumption
(each coil)
kg
DC
AC (VA) AC (VA)
W
inrush holding
2,3
9
23
3,8
9
23
3,8
9
23
7,5
9
23
17,6
6
40
14
14
14
14
22
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