DEWATERING VALVE
Historically, the dewatering valve has been used on dewatered
municipal sewage sludge, which tends to have seepage. This valve is used so
there will be no dripping of this seepage below the valve when in the closed
position.
A valve designed for fluid can seal against high
pressures. A valve designed for bulk solids can operate under high head loads.
When handling a material such as sludge, it is desirable to shutoff both solids
and liquids. Solid, non-compressible particles interfere with the seals of a
fluid shutoff valve.
Cleveland
Armstrong's® dewatering valve (RS-DW) is a modified slide
gate. Advantages for this unit include:
- Simple proven design widely used in waste
water treatment
- Sloped dewatering trough
- Wash out connection on dewatering trough to
help avoid plugging of drain port
- Seal arrangement that allows liquid to seep
into dewatering trough
- By using our standard rolling slide features,
we are able to keep the cost of the valve down and avoid exotic
designs.
- The retaining walls allow liquid to seep
through the seals, draining down the sloped blade and into the dewatering
trough.
- Using a sloped trough helps assure the
liquids run toward the drain port.
- Our customers are assured of a field-tested
and proven valve with a number of installations in the market place.
This valve is typically used on slurries,
filter cakes, sludge, wet sand or places where you need to contain liquid
seepage. Many applications involve truck loading.
DEWATERING SLIDE GATE OVERVIEW
The idea of designing a valve, which provides
watertight integrity along with the intrinsic ability to handle bulk solids, is
difficult to achieve. Normal valve designs used for the termination of the flow
of liquid or gases have
seating/sealing systems with pockets and ledges. In applications where liquids
and gases are handled, these ledges and pockets do not create problems. However,
when handling bulk solids, these areas fill up with solid material and impede
the closure of the valve and subsequent liquid tight sealing capabilities of the
valve.
Watertight gates using elastomer seals provide
excellent service life in applications where abrasive solids are not present.
However, when handling solids, the abrasiveness of the media greatly decreases
the life of the elastomer seals typically used in watertight valves.
PEBCO®'s
approach has been to modify its proven bulk solids handling valve to allow
the small amount of water which passes our seals to be directed into a drain
system. This design provides a number of advantages.
First of all, the valve is intrinsically
designed to handle bulk solids. This means there are no ledges, pockets, or
seats that the blade must move into in order to achieve a seal. The seals are
located on the top surface of the blade. The blade moves underneath the seals so
the seals act as both a wiper and seal. The blade is never driven into a pocket
or a seat and the blade support system is designed so the bulk solids do not
build up on the support system.
The small amount of water that leaks past the
seals on a PEBCO® valve is directed into a collection trough
at the end of the valve. This collection trough has a drain fitting which the
client ties into their existing waste water drainage system. This design
eliminates the leakage of solids and liquids both to atmosphere and below the
valve. But most importantly, PEBCO®'s
design provides extremely long service life and a minimum number of seal
replacements throughout the life of the valve.
DEWATERING GATE BENEFITS
- CONSTRUCTION - Construction is of A-36
steel on the body. This allows for flexibility in the manufacturing of the
gate, as well as the use of structural channel frame and structural
angel.
- GATE BLADE CONSTRUCTION - The gate
blade is constructed of A-36 and supported by cam followers. These cam
followers are heavy-duty and located out of the material flow
stream.
- Because of the design of the gate blade and
retaining walls, no adjustment is needed for the clearance between the gate
blade and the frame.
- GATE BLADE - Instead of having a
sloped blade with gutters running along the side, PEBCO® has
a simplified design. We provided a blade which has vertical wall on the two
sides and back of the blade. Any dewatering liquids flow beneath the seal and
are contained by these retainer walls. The liquid moves to the front of the
gate blade, which is open, and flow into our dewatering trough.
- DEWATERING FEATURE - The dewatering
trough is a stainless steel trough with a drainage connection and a wash out
connection. The sloped trough is designed to carry away liquids so to have a
drip tight gate.
- SEAL ARRANGEMENT - The seals are heavy
duty neoprene which extends from the gate frame down to the gate blade. This
seal is held in place by seal retainers. This helps to assure good sealing
between the blade and the frame.
- PEBCO® / Cleveland Armstrong® has
numerous valves in operation for dewatering applications since
1970.