|
 |
 |
HVAC & PLUMBING TRADE TALK |
|
|
F E B R U A R Y, 2 0 0 8 |
|
| News for the Commercial, Residential and Wastewater Trade |
We are happy to report that user subscriptions to our HVAC & Plumbing Trade Talk newsletter have grown significantly since our
first issue last November. If you know someone who would benefit from the newsletter, please pass along this email to them.
New users can subscribe at http://rcwapp.itt.com/BG-Newsletter-Form.asp.
How do you know if you are a candidate for this newsletter? Ask yourself these questions:
Has your spouse ever yelled at you for sneaking into the boiler room of your kid’s school on your way to a parent meeting?
When someone is giving a house tour, do you go straight to the basement?
Have you ever slow-motioned a movie DVD when the hero chases a villain through a mechanical room so you can get a better look at the equipment?
Have you ever corrected a family member in a condescending tone when they called those big back-flow preventers on the side of a road a pump?
Do you know the complexities of getting drinking water to the top of a skyscraper or flushing a toilet that is located below a sewer line?
Do you prefer "This Old House" and "Mythbusters" over "American Idol" and "Dancing with the Stars"?
If you answered yes, to any of these questions, you should subscribe. And if you have a question to add to our
"How do you know" list, send it to us for use in a future newsletter.
Your ITT Trade Talk Team
|
Pump Sound Levels: Practical Tips for Reducing Pump Noise
|
|
|
How much noise will a hydronic pump produce when it is installed in the field? The number of variables that affect noise
production are far too numerous to quantify by testing. For a given pump model with impeller size and horsepower, the noise
produced by the pump will be affected by the duty point, NPSHA, piping installation, pump installation, motor type, motor
enclosure, and motor manufacturer.
The Hydraulic Institute discusses noise production in their 2000 pump standard.
The ANSI/HI 1.4.6.2-200 and 1.3.4.5 Hydraulic Institute guide for Centrifugal
Pump for Nomenclature, Definitions, Application and Operation states that most
centrifugal pumps are classified as quiet machines. Typically the electric motor driven
pump will have a greater contribution from the motor to the overall noise
level than that contributed by the pump. For those applications where minimum
noise levels are required, the primary application rule is to select the pump at
both a conservative RPM and liquid velocity level. This will often rule out the
smallest, most economical pump that will operate at the highest possible speed
and with high liquid velocities. A quiet installation also demands complete
freedom from possible cavitation, and this means conservative NPSH margin.
Hydraulic noise can be the result of pump operation at flow rates below or well
above the design flow rate of the pump. Higher specific speed pumps are
more sensitive than lower speed pumps in this regard.
To learn how to reduce pump noise go to
http://www.bellgossett.com/Articles/files/MagazineArticle6.pdf.
|
Minimum Control Head & Variable Speed System Design
|
|
|
While "Green" is a hot topic today, HVAC Engineers have always been concerned about energy consumption. Pumps and fans can cost
a considerable amount of money to operate. Slowing equipment down so they match the system load and save money just makes sense.
ESP-PLUS includes a tool to help justify the additional cost of variable speed equipment. One of the key inputs required for this
tool, Minimum Control Head, plays an important role in variable speed operation and energy cost savings.
Read More
|
Pre-wired circulators simplify domestic hot water recirculation systems
|
|
|
Bell & Gossett offers a complete line of all bronze and stainless steel circulators that are pre-wired with a conventional 3
prong plug and 12’ cord. Units are also available with programmable timers to enable pump operation to be tailored to the hot
water load profile of the building. ON-OFF Aquastats are available to further fine tune the system and maximize energy
efficiency.
|
How does it work?
|
|
|
Have you ever wondered how things around you work? How does a relief valve protect the system, what is the purpose of an
expansion tank, why is a Triple Duty Valve called as such... On this new segment of the HVAC Plumbing and Trade Talk, we will
start dissecting some devices and figure out how they function. Let’s start with the Differential Bypass valve.
Click here to read more.
|
|
|
|