Often times when designing a HVAC or Industrial Process system we use unfired heat exchangers. Our choices vary between shell and tube design or plate/frame design. The next few Monday Morning Minutes will offer a glimpse of the variety of plate type exchangers. Today let’s look at three gasketed plate heat exchanger designs and the application of
Centrifugal Pumps – “Clipping the Tips”
R. L. Deppmann regularly receives questions when a field problem pops up. Here is an example call from an industrial user with a pump issue. There is an existing Bell and Gossett model 1510-5BC with a capacity of 1000 GPM at 60 foot head using a 25 HP, 1750 RPM motor and a 9” cut impeller.
Centrifugal Pump Selection Specifying Future Conditions
In the last R. L. Deppmann Monday Morning Minutes, we suggested a specification that would allow a future impeller change as a means of adding some safety factor to the pump provided on your project. What happens if you want to select a pump with a present and future condition? Here is a good pump selection for a capacity of 2700 GPM at 100 foot head using a 100 HP 1750 RPM motor.
Constant Speed Pumps and Maximum Impeller Concerns
How many times have you, as an engineer, looked at a number of curves and passed up a few because you did not like something about the selection on that curve? In the last R. L. Deppmann Monday Morning Minute we looked at end of curve selections. Today we examine pump selections near the top of the…
Centrifugal Pump Selection Maximum Point on the Curve
How many times have you, as an engineer, looked at a number of curves and passed up a few because you did not like something about the selection point on that curve? In the December 6, 2010 R. L. Deppmann Monday Morning Minutes, we look at how to specify and schedule pumps to limit the bidders to to specific pump curve characteristics.
Pump Selection – Flat vs. Steep Curves
An engineer in Michigan called about a large project with several pumps being selected in parallel for a plant chilled water system. He commented that the Bell and Gossett pump curves are flat vs. processing pumps which often times are steep. His question was, “Why are B&G curves so flat?” I’ve not heard this comment for many years. What did he mean? The term steep curve comes from the process industry. This old term refers to a large change in pump head with a small change in flow rate.
Large Centrifugal Inline Pump Installation
In our last Monday Morning Minute, we suggested using the Base Mounted Bell and Gossett series 1510 series end suction or VSX series double suction pumps when the design capacity requires over 10 HP. We do occasionally see our series 80 and series 80-SC inline pumps specified in applications up to 100 HP. Often the reason used for this application is limited floor space. Today let’s examine floor space required by these pumps.
Centrifugal Pump Selection for Hydronic Systems (Part 2)
You’ve selected the GPM (gallons per minute) flow rate and the pump head. You corrected the head for the fluid as described in the last few articles. It’s time to select a pump. Why do you select one pump over another and how do you, as the specifying engineer, make sure the submitted pump is remotely close to the one you selected. The R. L. Deppmann Monday Morning Minutes continues Pump Selection today.
Centrifugal Pump Selection for Hydronic Systems (Part 1)
You’ve selected the GPM (gallons per minute) flow rate and the pump head. You corrected the head for the fluid as described in the last few articles. It’s time to select a pump. Why do you select one pump over another and how do you, as the specifying engineer, make sure the submitted pump is remotely close to the one you selected. The R. L. Deppmann Monday Morning Minutes looks at this starting today.
Glycol in for HVAC Systems (Part 3) – Pump Corrections
R. L. Deppmann Company Monday Morning Minutes addressed corrections to system GPM (gallons per minute) and system friction head during the last three weeks. Today we look at the pump selection. Centrifugal pump curves and the brake horsepower required changes depending on the fluid. In HVAC design we normally assume water is the pumped fluid. There are many times when the assumption is water, since there is no fluid mentioned on the schedule, yet we find a glycol makeup unit attached to the system.