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TL-120

 

Figure 1: Two non-metallic pumps assure

dependable delivery of neutralizing

chemicals in the Gaylord scrubber

design. Controlled feeding of 50%

sodium hydroxide is provided by a Vanton

Flex-i-liner® rotary pump which supplies

it on demand from the pH probe in the

fiberglass sump. Continuous

recirculation of the neutralizing fluid

is accomplished with a Vanton

polypropylene cantilevered shaft, sump

pump.

Pump Upgrading Improves

Scrubber Performance and

Reduces Down Time

INDUSTRY:

ENTITY:

SOLUTION(S) PUMPED:

PUMP TYPE(S):

Chemical

Gaylord Foundry Equipment, Inc.

Caustic soda, Sodium hydroxide, Sulfuric acid

FLEX-I-LINER Sealless Self-Priming Peristaltic Pumps,

SUMP-GARD Thermoplastic Vertical Pump

 

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Reprinted from Pollution Equipment News

 

The management philosophy behind the quality reputation of packed

tower recirculatory scrubbers manufactured by Gaylord Foundry

Equipment, Inc. of Independence, Missouri combines the Truman "the

buck stops here" doctrine with the Gaylord belief that "building it better

isn't an option, it's the way we do it."

 

This explains why, despite the broad acceptance of their equipment, the

engineering department recommended a major design change which

involved upgrading the two pumps which are critical to continuous,

safe, environmentally satisfactory and economical performance of their

scrubbers.

 

An analysis of reported field problems indicated that the prime cause of

downtime and maintenance could be traced to pump failures under the

severe operating conditions they had to face. Depending on the

specific service, the pumps had to be able to handle dilute, as well as

concentrated sulfuric acid or sodium hydroxide. The use of these

scrubbers in conjunction with resin bonded core/mold operations in the

foundry, involves additional problems of abrasion from sand particles.

Not only must all wetted parts of the pumps be inert to the corrosive

chemicals, but they must be highly impact- and wear-resistant as well.

To better understand the scrubbing systems, let's examine a typical 13' 10" tall 4000 cfm SO• packed tower scrubber as shown in the accompanying sketch.

 

The SO• gas coming from the core machines enters through the air intake

and flows upward through a deep bed of packing media consisting of

polypropylene slotted ballast rings. Prior to the start of this upward flow of

SO• gas, the packing rings have been, and continue to be, thoroughly wetted

by a 5% by weight caustic solution supplied from the 190 gallon fiberglass

sump tank.

 

In the original design, Gaylord used an externally mounted centrifugal

plastic pump for the continuous circulation required. Due to repeated

failure of the carbon seals, and the messy cleanup required, the design

engineers replaced this pump with a Vanton polypropylene SGH vertical

sump pump. This resulted in the elimination of the seal and cleanup

problems. The SGH pump utilizes an integral pump/motor cantilever

shaft and requires no seals or sleeve bearings in contact with the

pumped fluid. The hollow shaft motor is protected from corrosive

fumes by means of a special vapor seal. No metal contacts the fluid.

Even the stainless steel shaft is sleeved in thermoplastic. Flow is

maintained at 155 gpm against a 65' tdh.

 

The caustic solution is pumped through the spray nozzle in the shower

head, which thoroughly saturates the packed media. The neutralized

scrubbed air passes from the packed media through a 6" thick high

efficiency polypropylene mist eliminator pad. The fine knitted wire

mesh takes out the suspended droplets of caustic solution, allowing

only clean, dry air to return to the atmosphere through the exhaust

blower. The entrained fluid drains back into the sump.

 

The use of a pH probe constantly monitors the recirculation solution,

which must be kept highly alkaline to assure neutralization of the sulfur

dioxide gas. When the ph drops below 8.5 the scrubber automatically

regenerates itself. This is accomplished by discharging a portion of the

spent solution, energizing the caustic transfer pump to meter a

controlled quantity of chemical and then adding make up water until the

sump is at its preset level.

 

In the original design, Gaylord employed a bellows pump. Experience

showed excessive maintenance and long lead time to secure

replacement parts. The new designs incorporate a Vanton ¼ HP

Flexi-i-liner® rotary diaphragm pump which has demonstrated greater

reliability and more accurate metering of the concentrated sodium

hydroxide on demand.

 

The Vanton design incorporates a Hypalon flexible liner in a Teflon body

block. The pump is self-priming, completely sealless, and inert to the

caustic. There are no stuffing boxes, check valves, gaskets or other

potentials for leakage.

 

Gaylord also manufactures a similar scrubber for the foundry industry

that uses a sulfuric acid based scrubbing solution. Since the Vanton

pump designs limit fluid to nonmetallic materials that are compatible

with sulfuric acid and caustic soda, purchasing and inventory

requirements are simplified, and pump maintenance is cut to a

minimum.

 

According to Gaylord's vice president, Kevin Crawford, there has not be

a single reported pump failure since the pump upgrades went into

effect more than a year ago.

Copyright 2016 - Vanton Pumps (Europe) Ltd - All rights reserved

About Us

In the 1950, Vanton developed a revolutionary all-plastic pump for use in conjunction with the first heart-lung device. The design limited fluid contact to only two non-metallic parts: a plastic body block and a flexible liner. This was the birth of our Flex-I-Liner rotary pump. Its self-priming sealless design made it an industry standard for the handling of corrosive, abrasive and viscous fluids as well as those that must be transferred without contaminating the product. Vanton now offers the most comprehensive line of thermoplastic pumps in the industry.

 

 

Stay in touch

mail@vantonpump.com

(+44) 01260 277040

Vanton Pumps (Europe) Ltd.

Unit 4, Royle Park

Royle Street

Congleton CW12 1JJ

UNITED KINGDOM

www.vantonpump.com