ROUND UP
When a globe valve is no longer functioning cor-
rectly or not at all, due to a broken linkage, leaky
hydraulic actuator, non-functioning electric or
pneumatic actuator, it can be easily retrofitted.
Many valves can be retrofitted with new linkages
and actuators, putting them back into service in a
relatively short time. Precision is the key to a suc-
cessful valve retrofit.
Mitech has retrofit solutions for almost any globe,
butterfly or ball valve application and can even build
customised linkages for those valves which have no
direct retrofit solution.
New internals and top works can be fitted to an
original valve body.
In many cases when an existing valve needs to be
replaced in a plant, the valve body is still in good
condition but the trim is no longer suitable.
Mitech’
s trims can be designed to suit the appli-
cation, and can be selected from the complete
range right up to the energy dissipating disk
stack.
Materials will be chosen to ensure safe op-
eration and long life. Below 150 mm or 600#
the cost of retrofitting generally will not be
justifiable, but with larger sizes and high pres-
sure rating valves, it becomes progressively
more worthwhile.
With the escalating cost of valves, re-engineering
existing valves is becoming increas-
ingly attractive.
Enquiries: Pieter Badenhorst.
Tel: 011 657 6000 or
email
If the flow velocity in a loop reduces, it can fall below
a critical value. When the
GEMÜ
650TL diaphragm
valve is used, selected tapping points can automati-
cally be closed by the central process monitoring sys-
tem in order to reduce the tapping quantity and thus
increase the flow velocity. It is now possible to query
the position of the handwheel. In this case, the posi-
tion ‘handwheel closed’ is detected by an optionally
available proximity switch and communicated to the
plant control system. Previously, this was only possi-
ble for the piston position of the actuator. Due to this
improvement, a visual check of the plant in person is
no longer absolutely essential.
The position ‘handwheel
closed’ can be checked sim-
ply and conveniently from the
control room.
This optimisation adds to the
reputation of the GEMÜ 650TL
as a ‘safety valve’, because the
additional functionality further
contributes to protecting plant
operators and the conducted
medium. Even if the valve
closes due to the prevailing
parameters (shut-off control air)
and the operator inadvertently
forgets to close the hand wheel,
uncontrolled escape of the
medium can still be prevented.
At the 2013 SIPEC trade fair
in Orléans (France), the Innova-
tion Prize went to GEMÜ for
the development of its
innovative GEMÜ 650TL
‘safety valve’.
Enquiries:
Eva Zink. Email
Valve retrofit service
Diaphragm valve recognised at
SIPEC trade fair
General purpose control valves
VALVES + ACTUATORS
Mitech
’s range of Globe control valves includes two-port globe, three-way
globe, two-port angle and sweep-angle types that are available in a choice
of carbon steel, stainless steel, bronze, chrome moly or special alloy body
materials.The valves’ modular design makes them easy to specify, reducing
spares inventory requirements.
The general-purpose globe control valves provide precise control across a
wide range of applications from standard to severe service. Robust in design,
the valves are available in DN15 to DN600 (½” to 24”) sizes, ASME 600# and
can accommodate all trims and accessories, as well as different end connec-
tions. Special trims are offered including low noise, anti-cavitation, cryogenic,
heat extended, soft seat, and pressure balance types. All trim components
are self-centering and are designed to clamp in place allowing the valve to be
quickly configured to the user’s specific process needs.
Actuation is either pneumatic, piston spring return, or double acting, electric,
modulating or on/off control. Flow characteristics include fast opening, linear
and equal percentage. Stem seals are available as
PTFE, graphite, bellows or live loading types. If
required, the valves can be adapted for use with
corrosive fluids.
Mitech’s globe valves are suitable for
high pressure and extreme temperature
conditions and are designed for use
with pneumatic, electro-pneumatic or
smart positioners. The valves are
ideal for use in petrochemical,
mining, food, breweries, pulp
and paper, power generation
and iron and steel applica-
tions.
Enquiries: Pieter Badenhorst.
Tel. 011 657 6000 or email
Electricity+Control
July ‘14
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