Page 2 • MN01029 Issue/Rev. 0.5 (6/11)
Section 1 – General Information and Description
It  is  suggested  that  a  detailed  record  be  maintained 
for each meter. Nameplate data, clearances, progres-
sive  totalizer  readings,  meter  factor,  parts  used,  and 
other similar information provide background material 
for scheduling a preventive maintenance program. An 
increase in meter factor drift against throughput can be 
used as the basis for making an inspection.
The time of the first inspection must be based on the 
operating conditions imposed by the installation. Flow 
rate, lubrication properties of the fluid, and the possibility 
of abrasive contaminants are points to consider. Then, 
at  the  time  of  inspection,  the  condition  of  the  meter 
should indicate whether the inspection interval can be 
lengthened or shortened.
All parts, as  they are  removed, should  be thoroughly 
washed  and  cleaned  in  solvent.  Parts  that  are  worn 
enough to affect operation or calibration should be re-
placed. All parts that are nicked, gouged, or have rough 
places on them, should  be  dressed  with a fine file or 
crocus cloth, as conditions warrant.
Before any disassembly is performed on the meter, be 
sure that the trouble is in the meter.
1.  Check that meter is being operated within the proper 
flow rate. Refer to the nameplate on the side of the 
meter.
2.  If rotor does not turn freely, adjust end clearance. See 
Adjusting Rotor End Clearances, Page 9.
3.  Check calibrator for proper operation.
4.  Check air eliminator and strainer assembly.
5.  Check valve operation.
After all other accessories have been checked and found 
to be operating normally, the meter should be checked.
Description
Smith Meter
®
 single-case rotary meters are of the posi-
tive displacement type. The metering mechanism is a 
rotor assembly set in the housing. Pipe connections are 
confined to the housing, which means the rotor assem-
bly can be removed by taking off the cover assembly and 
lifting the rotor assembly out. Inspection, maintenance, 
and service is greatly simplified.
The measuring function is accomplished in a chamber 
of precise volume created by the moving blades, rotor, 
housing, and cover. There is a smooth flow of product 
through  the  meter.  The  blades  rotate  around  a  fixed 
cam which causes them to move out to, but not touch, 
the body of the meter. Four chambers per revolution are 
formed as the rotor and blades are turned by product 
flow.
FMC  Technologies  Measurement  Solutions,  Inc.  pro-
vides  a  meter  variation  with  tungsten  carbide  trim  to 
resist the accelerated wear that can be caused by im-
1-1/2"
3/4"
3/4"
9"
9"
2" Dia.
Figure 1
Figure 1A
purities such as sand and iron sulfide and also by the 
low lubricity of condensates. This variation uses solid 
tungsten carbide  journal rotor  and thrust  bearings.  In 
addition,  blade  bearings’  size  and  weight  have  been 
reduced  to  minimize the  rotational  inertia  of  the  cam 
followers and the wear resistance of the bearings and 
cam have been substantially increased. Also, the rotor 
and jackshaft gear assemblies have been changed to 
hardened stainless steel.
Figure 2 — Spider and Bushing
1  Consists of feeler gauge soldered to 15" rod. An extension rod (22") and coupling is available as Part Number 515250.