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Guide to Gear Pumps
An Introduction to Gear Pumps

Gear Pump Basics (pdf)

Metering with Gear Pumps (pdf)


Questions?
Contact us for your application needs

Special Requirements?
Liquiflo can custom engineer pumps to meet the specific requirements of your application

 

 

 

 

 
The 3-Series Gear Pumps have been replaced by the H-Series gear pump line. The H-Series is recommended for all new applications as well as an upgrade to any existing 3-Series installations.
 

Liquiflo's original 3-Series gear pumps are available in Sealed and Mag-Drive versions with flows up to approximately 55 GPM and differential pressures up to 100 PSI.

 
 
Models 31-39 Sealed
Models 31-39 Mag-Drive
Models 312-314 Sealed
Close-Coupled
Close-Coupled
Long-Coupled, Bare Pump
     
Models 312-314 Mag-Drive
Models 31-39 Sealed
Models 312-314 Sealed
Long-Coupled, Bare Pump
Long-Coupled, Base Mounted *
Long-Coupled, Base Mounted *
 
 
* Sealed pump shown long-coupled to motor; assembly includes coupling guard (not shown).
 

3-Series Specifications
Click any Model # below to access page for that individual model:
 
  3-SERIES MODEL   31F 33F 35R 35F 37R 37F 39R 39F 312R 312F 314F  
  Port Connections:
 NPT/BSPT
 ANSI 150# RF FLG
 DIN PN16 FLG

in
in
mm

1/4
1/2
10

1/4
1/2
10

1/2
1/2
15

1/2
1/2
15

3/4
3/4
20

3/4
3/4
20

1
1
25

1 ¼
1 ¼
32

1 ¼
1 ½
40

1 ¼
1 ½
40

-

65
 
  Max Flow Rate
GPM
0.5 1.4 2.4 3.4 8.6 10.7 15 21.5 22 29 58  
  Max Diffferential Pressure
PSI
100 100 100 100 100 100 100 100 100 100 100  
  Max Discharge
Pressure
PSIG
300 300 300 300 225 225 225 225 270 270 270  
  Max Temperature
°F
500 500 500 500 500 500 500 500 500 500 500  
  Max Speed
RPM
1750 1750 1750 1750 1750 1750 1750 1750 1150 1150 1150  
  NPSHR @ Max Speed
ft
3 2 2 2 5.2 5.2 4 3 5 5 5  
  Weight (without motor)
 Sealed, Long-Coupled 
 Sealed, Close-Coupled
 Mag, Close-Coupled
 Mag, Long-Coupled
lbs

2.5
23
31
-

2.5
23
31
-

3.5
24
32
-

3.5
24
32
-

6.5
29
36
-

6.5
29
36
-

8
34
38
-

10
36
40
-

52
-
-
70

52
-
-
70

67
-
-
85
 
   
Note: Model 311F has been replaced by Model H9F. The performance curves for Model 311F are located in the Documentation section. Contact factory for additional information.
   
 
 
Available Materials Of Construction  
 
 
 
Available Sealing Configurations  

Magnetically Coupled (sealless)

The magnetically coupled or mag-drive pump is the best method for handling toxic, noxious, crystallizing, or most other hazardous liquids since it completely contains the pumpage by isolating the drive shaft inside the pump housing. With no dynamic seal to leak or replace, the maintenance issues associated with seal leakage are eliminated. All Liquiflo gear pumps are available with magnetic drive.

   
Mechanical Seal

Mechanical seals are offered in single, double and external configurations and are used for chemical applications where leakage needs to be minimized or eliminated. The single internal mechanical seal is the most common seal type and is ideal for pumping clean liquids up to 5,000 cP viscosity. The double mechanical seal requires a flushing system and is typically used when pumping liquids that are viscous, abrasive, crystalize on contact with air or are very hazardous. The external mechanical seal is used to isolate the seal body from the pumpage or when pumping liquids under vacuum conditions. Carbon vs. SiC seal faces are the primary choice for most applications up to 500 °F. SiC vs. SiC seal faces have high abrasion resistance and can be applied up to 500 °F. Teflon vs. SiC seal faces have extreme chemical resistance and can be applied up to 180 °F and 50 PSI differential pressure.
   
Packing Seal

Packing is the simplest and most economical solution for pumping non-hazardous liquids where minor leakage is acceptable. Braided Teflon packing is the primary choice for applications up to 350 °F. Graphoil packing is available for high temperature applications up to 500 °F.
 
 
 
Available Options & Accessories  
 
Replacement Cartridge
A cartridge is a complete mag-drive pump less the outer magnet and pedestal. A cartridge replacement is a convenient way to quickly replace a mag-drive pump that requires maintenance, ensuring maximum uptime.
Relief Valves
Positive displacement pumps should be installed with a relief valve in the discharge line to protect the pump and piping against any type of line blockage including the inadvertent closing of an isolation valve. Liquiflo manufactures two sizes of relief valves in both 316 SS and Alloy-C.
Repair Kits
Repair Kits simplify inventory and speed repair. All parts can also be purchased separately. (See also Replacement Cartridge for even quicker repairs.)

Close-Coupled Configuration
All Liquiflo gear pumps are available with the close-coupled configuration. This configuration simplifies installation and maintenance, and extends pump life by guaranteeing perfect pump-motor alignment.
Raised-Face Flanges
ANSI, DIN, and JIS Flanges are available to simplify piping connections and disconnections.
Sanitary Fittings
Tri-clamp sanitary fittings are a convenient alternative to threaded or flanged port connections.
S-Adapter
The S-Adapter is available for long-coupling mag-drive pumps; it isolates the pump from the motor and can be used when long-coupling pumps to motors or drives that do not have a C-face mounting. Maximum temperature rating is 250°F (120°C).
Power Frame
The LIQUIFLO power frame is used for long-coupling mag-drive pumps that are used for high temperature applications, up to the pump's maximum temperature rating. Its integral cooling jacket keeps the bearing system of the pedestal cool even when it is coupled to a pump operating at extremely high temperature.
Clamp-On Temperature Control Jacket
Temperature Control Jackets can maintain the pump at either elevated or reduced temperatures. They are commonly used when pumping liquids that solidify or become difficult to pump when the temperature decreases.
Dual-Kan™
Liquiflo's patented Dual Kan controls the back-end temperature of a mag-drive pump by circulating a heating or a cooling fluid through the containment can. This is ideal for applications requiring precise and uniform temperature control.
Base Plate Mounting
Liquiflo gear pumps are available with base-mounts to simplify installation. Liquiflo also offers base-mounts with or without the motor pre-installed.
Hard-Coated Shafts
Hard-coated shafts are used to extend pump life in difficult applications requiring higher levels of wear resistance. Ceramic Chrome Oxide (CO) and Tungsten Carbide (TC) coatings are available.
Accessories & Spare Parts
Mechanical couplings, coupling guards, risers, base plates, adapters, brackets, pedestals and individual pump components can all be purchased separately.
   
 
 

 

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