Horizontal end suction centrifugal pumps are undoubtedly the most common pumps in use in the world today, yet I witness basic misunderstanding of the pump specification almost every day.
I thought it might make for an informative and fun quiz to go over some of the more misunderstood sections of ASME/ANSI specification B73.1 (2012).
As an editorial comment solely on my part, the ANSI pump geometric design parameters are based on old technology. The original designs were based on pumps and applications with packed boxes and lower energy levels. Today, the basic ANSI pump design is shackled with high shaft deflection ratios, low efficiencies and inadequate seal chamber options. Some of these deficiencies can be addressed with options and auxiliary systems, but pump manufacturers and end users probably wish we could start the design over with a new blank sheet of paper. Who is going to tackle this problem?
Choose the most correct answer.
You should budget approximately 20 minutes to complete the quiz. When you finish, click here to see the answer key.
1. The modern version of the ANSI B73.1 specification has its roots in the AVS (American Voluntary Standards) from the 1950s.
2. Flanges: Bolt holes may be drilled and tapped when there is inadequate space for nuts behind the flange.
3. When a heating jacket is used the steam inlet shall be:
A) On the top and the drain on the bottom
B) On the bottom with the drain/vent on the top
C) Inlet and outlets should be on the sides to allow for ease of piping.
D) None of the above.
4. Impellers shall be balanced to this standard at a minimum:
A) NASA standard CFR 1928:WWYATQ -2
B) ISO 1940-1 Grade 6.3
C) ANSI standard B20-22A (balance of metallic impellers)
D) ASME B638.637
5. If the method of impeller attachment is threaded, the pump rotation shall have the shaft (design) function to tighten the impeller:
6. The casing drain connection shall be drilled and tapped only when specified by the purchaser. Otherwise, there will be no drain penetration. Further, the manufacturer shall always provide a casting “boss” at the lowest point on the casing to accommodate at a minimum a ½ in NPT penetration when specified.
7. Pump operating clearances shall be adequate to prevent internal rubbing when the pump is subjected to the maximum allowable flange loads (pipe strain) when operating in the allowable operating region (AOR).
8. Pump shaft “runout” on new pumps shall be no more than 0.001 inches when measuring the shaft on centers, and 0.002 inches when the shaft is installed in the pump.
9. Bearing life (L10) shall be a minimum 37,500 hours if the pump is operated in the allowable operating range.
10. Standard lubrication design for the bearing frame is set for:
A) Oil mist lubrication
B) Sealed for life bearings
C) Greased bearings
D) Oil bath
11. The bearing frame shall include a drain plug that is:
A) Non magnetic
B) Manufactured from either aluminum, kryptonite or nonobtainium
C) Easily removed and reinstalled using a Phillips screwdriver
12. The bearing frame when set up for oil bath lubrication shall have:
A) A bull’s eye level indicator
B) The option for the bull’s eye indicator to be mounted on either side of the pump
C) The bull’s eye level indicator will be 1 inch in diameter.
D) All of the above are true.
13. Gland bolt stud and nut materials can be made from grade B7 and 2H carbon steel.
14. The minimum casing corrosion allowance is:
A) 0.125 inches
B) 0.250 inches
C) 0.500 inches
D) 0.120 inches
15. The direction of rotation when viewed from the driver perspective shall always be:
C) Doesn’t matter as long as the customer specifies which one
D) Clockwise, but only if using a variable frequency drive or if pump shaft is oriented in the vertical plane. Otherwise, it must be counterclockwise.
16. A lifting eye is to be provided on the motor and shall be capable of lifting the entire weight of the motor, baseplate and pump.
17. The bearing frame adaptor shall:
A) Be designed to resist any amount of torque that the shaft design can handle
B) Be manufactured from any material the manufacturer has left over in an effort to hold down costs.
C) Be painted yellow (spec USCG 637) or orange (spec USCG 638 International) in accordance with OSHA CFR 1929-638
D) None of the above
18. When testing the pump for noise:
A) The driver noise data must be determined separately.
B) The test shall be conducted in accordance with ANSI /HI 9.1- 9.5).
C) Must be conducted in an ultra-quiet test room per OHSA CFR 1929-4256
D) Answers A and B above
E) None of these answers