What do you expect
Beating my head against the wall
What do you expect
You want to take it all
("What Do You Expect?," by J. J. Cale, 1981)
THE EXPECTED, TYPICAL PUMP INSTALLATION SET UP
PTOA Readers and Students who are reading the PTOASegments in theintended sequential order just learned that ...
No matter which kind of pump is chosen for aprocess industry service ...
each pump will have:
- A casing that is fabricated to create a Pump Suction and a Pump Discharge.
- A Suction Pressure PI and a Discharge Pressure PI.
- A Pump Suction Pipe aka Pump Suction Line.
- A Pump Discharge Pipe aka Pump Discharge Line.
- A Tank or Reservoir.
In this PTOA Segment #164, PTOA Readers and Students will learn about the hardware components that will beinstalled on the Suction andDischargePipes of all pumps...
No matter whichtype of pump is chosenfor whatever process industry service.
The Typical Pump Installation Set Up is evident in the nearby photo.
The Suction Valve, Discharge Valve, Strainer, and Check Valve are labelled.
All PTOA Readers and Students who stick with the PTOA willsoon be able to identify the hardware components found in theTypical Pump Installation Set Up without any labels ...
and that will certainly impressany potential Process Industry employer!
REAL & SYMBOLIZED PIPE HARDWARE COMPONENTS
INSTALLED ON PUMP SUCTION AND DISCHARGE LINES
ISA Valve Symbols
The future PTOA PV Flowrate Focus Study Area will focus uponpiping hardware and thevarious methods used to connect pipe segments together ...so don'tsweat the details now.
At this juncture PTOA Readers and Students just need to realize that pipe hardware components include Valves and Filters.
The ISA symbols for common Valve Types used in process industry,
PTOA Readers and Students will learn that ... although there are many types of Valves ... there are only 4 reasons to add aValve into theprocess flow piping.
The above graphicshows the ISA symbols for popular process industry Valves.
For example, one of themost commonprocess industry Valves is theGate Valve.
Gate Valves are used to start orstopthe process flow.
That means that Gate Valves will either betotally open or totally closed.
The ISA symbol for a Gate Valve looks like a bow tie.
A real world manually operated Gate Valve is in the nearby photo.
This model hasa blue hand wheel.
The Typical Pump Installation Set Up
The Typical Pump Installation Set-up is shown in the below diagram ...
Don't fret, the symbols will be explained, right after a little "decoding of the schematic."
This diagram shows the Typical Pump Installation Set Up.
Note that the Centrifugal Pump in the diagram does not have the "backwards C." The symbol is also missing the Discharge Line spout ... because it was drawn with a cheap CAD program.
In this case Your Mentor can infer the diagram is showing a Centrifugal Pump that adds the PV Pressure to liquids and not aCentrifugal Compressorthat adds the PV Pressure to gases.
The drains are a dead giveaway.Liquids drain. Gases don't drain.
Now direct your attention to thebottom left of the diagram.
This diagram shows the Typical Pump Installation Set Up.
Although there are no arrows indicating flow, believe Your Mentor that the process stream liquid is flowing from itsTank/Reservoir and enters the diagram on the bottom left.
Find thebelow hardware components on the Typical Pump Installation Set Up diagram.
- A SuctionValve on the pump's Suction Line is a Gate Valve ... it is before the UC/Drain and looks like a bow tie.
- A DischargeValve on the pump's Discharge Line is also a Gate Valve... it alsolooks like a bow tie and is located just after the ....
- Check Valve ... whichlooks like"Z" with an arrow pointing the desired direction of flow.
The purpose of a Check Valve is to prevent flow from going in the non-desirable, reverse direction. The arrow on the check valve body indicates the desired flow direction.
This flow diagram shows The Typical Pump Installation Set Up.
PTOA Readers and Students will soon learn why ...
EachValve isinstalled for a specific purpose ... no Valve is justrandomly stuck in there for grins.
Don't stress about thepiping hardware shown in the upperregion of the schematic; PTOA Readers and Students will learn all about it in thefuture PTOA PV Flowrate Focus Study Area.
The Suction gate Valve, Discharge gate Valve, Check Valve, Pipe Diameter Reduction, Pipe Diameter Expansion are visible in this real world Typical Pump Installation Set Up.
In the nearby real world photo, theSuction and Discharge Gate Valves are easily identified by their black hand wheels.
The Check Valve ison the Discharge Line, bolted in-between two segments of piping that have flangedends... (just look for a drain spout pointing down).
Hardware Components That are Needed for Pump Malfunction
The Typical Pump Installation Set Up must take into account this question:
What happens if the Pump malfunctions?
PTOA Readers and Students who are reading the PTOA Segments in the intended sequential order already know that critical-service pumps are installed in pairs ... aPrimary Pump and a Back-Up Pump.
Logically, theBack Up Pump is placed in servicewhile the malfunctioning pump is repaired.
So also logically, some piping component hardware must exist to"block in and isolate" the malfunctioning pump from the process fluid ...
because the process fluid must still continueflowingso that raw materials can continuously be upgraded to more valuable products.
The General Steps To Prepare a Pump for Maintenance
The hardware pipingcomponents that are purposelyinstalled tomake it possible to "swap a pump out for maintenance" are explained below ...
While theactionsthat anOutsideProcess Operatorfollows to bring themalfunctioning pump "off-line" are simultaneously explained.
In general the procedure will include the following actions:
This pump starts automatically.
TheOutside Process Operator will either initiate the written procedures to startthe Back Up Pump or it will be started up automatically viaautomatic instrumentation.
- In either case theOutside Process Operator will confirm that theBack Up Pump is workingafter having been offline prior to proceeding to the next step because a limping pump is better than no pump at all.
- The Outside Process Operator will depress the"Stop Button" on the malfunctioning pump'sdriverso it will stop its spinning or reciprocating action.
- The Outside Process Operator will Block In the Suction Valve and Discharge Valve of the malfunctioning Pump.
In Process Operator jargon, the phrase "Block in" means"to close tightly and completely."
- The Outside Process Operatorwill open the drains and vents shown around the pump so that the process liquid, lube oil, and hot vapors from themalfunctioning pump are drained viaenvironmentally conscious procedures(DO NOT DUMP OIL on the ground!).
This graphic shows the Typical Pump Installation Set Up.
The Typical Pump Installation Set Up must also take into account this question:
What would happen if the Suction Valve or Discharge Valve were found to be leaking ... and maintenance still must be completed on the pump?
Opening up thetwo drains to sewer would encourage the leaking process fluid to "take the easy way out" and flow to the drain or sewer ...but thisplan-of-attack would not beasafe procedure nor would it complywithenvironmental permitting.
The designed-in solution is:
A real world Spec Blind
- The Process Operator will "swing thespectacle blinds" on the Pump Suction Line and Pump Discharge Line "to theclosed position."
The spectacle blinds on the diagram are those Figure 8 shaped things that look like spectacles (eyeglasses).
Take the time to locate the "spec blind" on the diagram. It is between the Suction Gate Valve and the (labelled) Drain.
This Spec Blind is Swung Closed. Flow is Blocked.
The dark circle represents a metal surface that, when swung into place, creates aphysical barrier in the pipe thatprevents flow from getting through. (Don't Stress! Pipe Fittingswill befeatured in the PTOA PV Flowrate Focus Study Area).
Although not shown on the Typical Pumping Installation Setup schematic,there will always be a Filter or Strainer of some type on theSuction side of the Pump.
The Filter/Strainer removes debris that wouldscratch theinternal working surfaces of any Pump.
This graphic shows the typical hardware that surrounds pumps. Missing are filters and strainers.
Centrifugal Pumps Require Suction Line Contraction
FollowedbyDischarge Line Expansion
See thetwo thimble-looking things, one piped in prior to the Pump Suction and the other piped in after the Pump Discharge?
The Typical Pump Installation Set Up.
These symbols indicate the pipe diameter is intentionally decreased just prior to thePump Suction and increased after the Pump Discharge.
The change in piping diameters is a permanent, planned feature of the piping scheme that is needed for centrifugal action to work properly and is not related to themaintenance interval.
So the complete Typical Pump Installation Setup For A Centrifugal Pumpis shown in the below schematic:
The flow to this Centrifugal Pump goes from Tank → Suction Gate Valve → Pipe Diameter Reducer → Pump Suction/Pump Discharge → Pipe Diameter Expansion → Check Valve → Discharge Gate Valve → Distribution Header Pipe
PTOA Readers and Students will soon expertly understand centrifugal action ... do don't fret about that now!
TAKE HOME MESSAGES: There is a Typical Pump Installation Set Up that is common to all pumps, no matter what their style of process service is.
The component hardware in the Typical Pump Installation Set Up includes:
- Suction Valve and Discharge Valves, which are typically gate valves that can be totally open or totally closed.
- Check Valve on the Discharge Pipe/Line to prevent backflow into the Pump Discharge.
- Filter or Strainer prior to Pump Suction.
- Pump Casing and Piping Drains.
The typical component pump piping hardware may also include:
- Suction and Discharge Spec Blinds.
- Pipe Diameter Reducer prior to Centrifugal Pump Suction.
- Pipe Diameter Expander at Centrifugal Pump Discharge.
This PTOA Segment included the general procedure that allOutside Process Operators follow to "swap out a pump for maintenance".
The Outside Process Operator must always verify the status of theBack Up Pumpprior to shutting down the Primary Pump (a limping Primary Pump is betterthan no pumping action at all).
©2017 PTOA Segment 0164
PTOA Process Variable PressureFocus Study Area
PTOA PV Pressure Rotating Equipment Focus Study