Efficient Plant December 2017 - 36

CHEMICAL
processing
FEATURE

Be Aware of
Wear Before
Failure

MICHELLE SEGREST
CONTRIBUTING EDITOR

A chemical-pump expert shows how preventive
maintenance can ensure chemical pumping performance.

nderstanding that ﬂow components such

years come from the technol-

as diaphragms and check valves will

ogy of automation and instru-

start to show wear before they fail can be strong

mentation built into metering

motivation to incorporate an effective

and dosing pumps.

preven-

tive-maintenance program for chemical-pro-

"Chemical pumps have

cessing equipment, according to metering-pump

come a long way," he ex-

expert Jim Holts, senior technical sales manager,

plained. "We must understand

dosing pump line, Grundfos Pumps Corp. (us.

that we now can get actual

grundfos.com, Downers Grove, IL).

feedback from the pump on

"It is very common in this industry to say, 'I'm

the control side. There are

going to wait until something fails, and then ﬁx it,'"

alarms and warnings that tell

Holts explained. "Proactive maintenance is the

us when the chemicals are

key. When the components start to wear, you will

not pumping properly. These

start to lose the accuracy of your pump, which is

pumps can actually correct

one of the reasons you bought a metering pump

themselves when they are

to begin with-for it's high, repeatable accuracy.

not pumping properly. They

And since we may classify metering pumps more

can calculate ﬂow and send

on the instrumentation side, just remember that

this information back to the

you are paying for something you are not getting

SCADA and control systems.

if you are not doing proper maintenance."

When I ﬁrst started in the

Holts has 37 years of experience in the

This chemical skid system
uses high-ﬂow hydraulic
pumps. All photos
courtesy Jim Holts

chemical-metering-pump busi-

Above left. It is very common to mount low-ﬂow pumps above
the supply tank on a wall-mounted system.
Above right. This is an example of a ﬂoor-mounted skid system.

positive-displacement pump-market, including

ness, these pumps were part

31 years in dosing/metering pumps. He has

of the instrumentation group. Then they became

accurately inject a variety of chemicals. These

worked with several companies and a variety of

part of the rotary equipment group. Now, with all

types of pumps fall into two categories-mechan-

positive-displacement pump technologies. He's

the controls and integration, you are seeing the

ically actuated pumps and hydraulically actuated

also a member of the committee responsible for

instrumentation people involved in the controls

pumps. As far as maintenance and reliability

the book Positive Displacement Pumps-Con-

and selections of chemical metering pumps."

functions are concerned, there are some simi-

trolled Volume for Petroleum, Chemical and Gas
Industry Services: API-675 Standard 3rd Edition.
According to Holts, the biggest advancements in chemical pumps within the past 10

36 |

RELIABLE PUMPING SUPPLEMENT

larities and some differences in the two types of

HOW THEY WORK
Metering, or dosing, pumps are usually reciprocating diaphragm-style pumps with the ability to

pumps, Holts said.
Both types have diaphragms, but in mechanically actuated pumps, the diaphragm is directly

DECEMBER 2017

http://us.grundfos.com

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