Table of Contents
Advertisement
Installation
Internal Valve
Coat both sides of the spiral wound gaskets with Dow
Corning #111 silicone grease or equivalent. An NPS 4 (DN
100), CL300 ASME RF flange with a modified bore (see
Figure 1) must be installed in the tank. Special stud bolts,
furnished with the valve, are assembled into this flange.
The internal valve and the pump or piping flange can then
be installed as shown in Figure 2.
The screen should be removed if the valve is to be used for
both filling and withdrawal service or for filling alone.
Filling with screen installed is not recommended.
A hydrostatic relief valve does not need to be installed
adjacent to the valve since the internal valve automatically
relieves excessive line pressure into the tank.
Keep piping from the valve outlet to the pump full size and
as short as possible with a minimum of bends. Reduction
in pipe size to suit smaller pump inlets should be made as
close to the pump as possible using forged reducers
(swage nipples) or venturi tapers rather than bushings.
This assures minimum flow resistance and efficient pump
operation.
The operating linkage must allow the operating lever to
move from the fully closed position to within 2° of the full
open position. The linkage should not apply strong force
to the lever past the full open position or the valve could
be damaged.
If the valve is also used to provide excess flow protection,
the flow rating of the piping, fittings, pump, valves, and
hose on both the inlet and outlet of the internal valve
must be greater than the flow rating of the integral excess
flow valve within the internal valve. If branching or other
necessary restrictions are incorporated in the system
which reduce the flow rating to less than that of the excess
flow valve rating, the internal valve will not give excess
flow protection.
After installation check all joints for leaks using a suitable
leak detector solution such as Marshall Excelsior low-temp
leak detector before putting the valve into service.
Selectively Filling Manifolded Tanks
MEC internal valves provide positive shutoff only in one
direction, from out of the tank to downstream of the
valve. The internal valves are designed to allow gas to flow
into a tank when the downstream line pressure exceeds
tank pressure. If you want to selectively fill one or more of
the other tanks in a tank manifold system, you must place
a positive shutoff valve downstream of the internal valve,
otherwise, all tanks will be filled at the same time and at
about the same rate.
FORM #1132 ME990-3F IOM
ME990-3F
Operation Methods
Figure 3: Fuse Assembly
Pulley Cable Assembly: On standard configuration ME990-
3F valves, insert the provided key ring through one hole in
the operating lever. Install the fuse link onto the key ring,
and then connect the fuse link to a control cable, see
Figure 3.
A remote operating handle is attached to the other end of
the cable. Since the remote operating system for the valve
is extremely important, it must be installed to conform to
applicable codes. DOT MC-331, for example, most
generally applies for trucks; refer to the most recent
revision of this code. Any control system requires thermal
protection (fuse links) at the valve, at the remote control
point and if necessary near the hose connections.
Rotate the valve's operating lever by hand to the position
shown in Figure 3. In this position the valve's cam is just
contacting the valve stem and the cable can be attached to
the remote operating handle. Check to see that the valve
closes properly and that the operating lever returns to its
original position. There should be a little slack in the cable.
Since there is strong spring force on the operating lever,
avoid getting in the way of lever if it slams to the closed
position. The lever should not be allowed to slam to the
closed position except in emergency situations, as
repeated slamming may damage the valve and operator.
Actuators:
The use of non-MEC actuators may result in leakage of
the gland packing caused by premature wear. In addition
to premature wear, the use of non-MEC actuators may
result in lower than expected flow rates and possible
leakage across the valve seats.
!WARNING!
NOTE
Rev C 2/3/21
Advertisement
Table of Contents
