pump alignment 1

[sb00]

Hi folks,
i was reading some where that pump alignment should be done at the operating temperature. Does it really make much of a difference if say, my operating temperature is below 60 C and i align the pump at 25 C?
Thanks...
-SB

 

[Paperpete]

It depends on the size of the pump. Thermal expansion is liniar so the actual alignment offset caused by this will vary with the size of the equipment. When I have pumps that pump very hot liquids such as boiler feed water I try to have them brought close to operating temp before alignment. In your case a good alignment tech. will use a special formula or chart to align the pump a little low depending on the process temp (if needed).

 

[stanking]

I assume you are talking about coupling alignment. We run hot oil pumps at 540 deg F. I use magnadrive coupling, which is aligned only with a straight edge. Since there is an air gap, no misalignment load is transferred to pump shaft/bearings/seal. Wonderful for extending life of these components. As an adder, you get soft start as well as torque limit disengage without stopping the motor. Check out

http://www.magnadrive.com

 

[poppeye]

Ingersoll Dresser/ Flowserve advises the following alignment guidelines for all pumps.

Motor and engine driver pumps.

Pump handling cold liquid.............Driver .005" to .008
lower than pump.

Pump handling hot liquid..............Driver .002" to .005
250degF or higher higher than pump.

Turbine driven pumps (Turbine having centerline support)

Pump handling cold liquid.............Turbine .005" to .008
lower than pump.

Pump handling hot liquid..............Turbine .001 to .004
(250degF) higher than pump.

Turbine driven pumps (Turbine without centerline support)

Pump handling cold liquid.............Turbine .020 to .023
lower than pump

Pump handling hot liquid..............Turbine .014 to .017
250degF. lower than pump.

Belt driven pumps (pulley on separately mounted Jackshaft)

Pump handing cold liquid..............Coupling halves within
.003

Pump handling hot liquid..............Jackshaft .006 to .009
250degF. higher than pump.

Once you have performed this cold alignment between the driver and pump, operate pump until pump and driver are to
full operating temperatures. Shut down your machinery and re-take your alignment readings. For units operating above 250deg. Hot alignment readings should be taken within 10-15 minutes of securing. You may find that due to pipe stress with temp increase, these calculations are just a starting point for your required alignment. Cold (prior to start) and Hot (units up to operating temp) readings should always be taken to ensure proper unit alignment.

Poppeye

 

[poppeye]

Ingersoll Dresser/ Flowserve advises the following alignment guidelines for all pumps.

Motor and engine driver pumps.

Pump handling cold liquid.............Driver .005" to .008
lower than pump.

Pump handling hot liquid..............Driver .002" to .005
250degF or higher higher than pump.

Turbine driven pumps (Turbine having centerline support)

Pump handling cold liquid.............Turbine .005" to .008
lower than pump.

Pump handling hot liquid..............Turbine .001 to .004
(250degF) higher than pump.

Turbine driven pumps (Turbine without centerline support)

Pump handling cold liquid.............Turbine .020 to .023
lower than pump

Pump handling hot liquid..............Turbine .014 to .017
250degF. lower than pump.

Belt driven pumps (pulley on separately mounted Jackshaft)

Pump handing cold liquid..............Coupling halves within
.003

Pump handling hot liquid..............Jackshaft .006 to .009
250degF. higher than pump.

Once you have performed this cold alignment between the driver and pump, operate pump until pump and driver are to
full operating temperatures. Shut down your machinery and re-take your alignment readings. For units operating above 250deg. Hot alignment readings should be taken within 10-15 minutes of securing. You may find that due to pipe stress with temp increase, these calculations are just a starting point for your required alignment. Cold (prior to start) and Hot (units up to operating temp) readings should always be taken to ensure proper unit alignment.

Poppeye

 

[JJPellin]

We only consider hot alignment to be necessary for pumps that run above 200 °F (about 95 °C). Below that, we align cold with no offset. With a good coupling, this should be fine. Our main problem with hot alignment is energy control. In order to satisfy our energy control policy, it takes much too long to get a permit and start an alignment. So it is necessary to calculate or measure cold alignment offsets. Once we started doing this, we found it was much faster and gave results that were just as good. We measure support temperatures on the pumps in normal operating conditions and calculate growth relative to standard ambient conditions. We then align the pump cold using the pre-calculated thermal offset numbers. This makes the alignment quicker, safer and more pleasant for the mechanic.

 

[sb00]

thnx guys, very informative and helpful as ever!