Mini Bellows Metering Pumps
Product Overview

Mini Bellows Metering Pumps are ideal for low flow, low pressure metering applications. The pump is constructed entirely of plastic and uses GRI's time-proven bellows technology to provide an accurate chemically-resistant metering pump with a long life, at an economical price.

Mini Bellows Metering Pump Operation:
The Mini Bellows Metering Pumps operate on a positive displacement principle. The rotation of the motor shaft is transmitted into an up and down linear motion through an adjustable concentric crank mechanism. This motion provides a continuous compressing and relaxing force on the bellows module, forcing fluid between two check valves located in the module's valve body. Up to two separate bellows modules can be operated by single motor for proportioning up to four separate fluid mediums. The flow rate of each module is independently adjustable. Multiple bellows modules operate out-of-phase with each other for most efficient power usage.

Optimum Operating Conditions:
Optimum operating conditions consist of a 6” minimum suction life and a discharge head of not less than 6”. Pumps must be mounted vertically with the valve body at the top to obtain maximum metering accuracy. For conditions where a positive suction head condition exists, an anti-siphon spring or anti-siphon spring kit can be added to aid the poppet valve seal properly during operation. See Accessories PDF file located in the Product Resources section located above right.

Bellow Metering Pump Flow Rates:
The flow rate of each bellows module is regulated by three factors:

1. Diameter of the bellows,
2. Speed of the gearmotor,
3. Adjustment of the module stroke length.

Bellow Metering Pump Flow Adjustment:
The ½” and ¾” bellows modules can be adjusted to 20% of maximum stroke length, while 1”, 1-1/2” and 2” bellows modules can be adjusted down to 10% of maximum stroke.

Note: Best priming and metering accuracy occurs when the stroke length is 50% or greater.

Standard Crank — Adjustment cannot be made while pump is operating. An adjusting screw changes the stroke length of an eccentric crank.

Mini Bellows Metering Pump Specifications:
Average Repeatability — From stroke-to-stroke ± 0.75%
Flow Rates — Range to 270 ml/min, Tandem models range to 432 ml/min
Max Fluid Temperatures — To 140°F (60°C)
Max Discharge Pressure — To 6 psi

Note: All testing is done with water at an ambient temperature of 80 degree F. If specific gravity or viscosity of fluid being pumped is significantly greater than water (1.0), please consult factory.

Gearmotors:
The standard motor available for the Mini Bellows Pump is an AC voltage synchronous motor. Motors are UL listed and continuous duty rated and are available in 115V, 50/60 Hz or 230V, 50/60 Hz.

Materials in Contact with Solution:
Connectors — Polypropylene
O-Rings (Elastomers) — EPT/EPDM, Hypalon®, or Viton®/Fluoroelastomer
Poppet/Duckbill Valves — EPT/EPDM, Hypalon®, or Viton®/Fluoroelastomer
Bellows — Standard Polypropylene Materials
Additional materials available, refer to OEM Section for details.

Mini Bellows Metering Pump Selection:
The pump selection procedure is detailed in the Mini Bellows Metering Pump Selection Guide link by navigating to any of the CBMP Series pumps listed below. Select a bellows size that meets your pressure requirements. Select a model with the bellows size that provides your required flow while operating closest to full stroke capacity. Best metering accuracy occurs when bellows modules operate at 50% or more of maximum output. For 24 hour continuous duty service, use one of the heavy-duty models.

Select a valve and O-ring combination and tubing connectors for each bellows from the selection charts at the end of this section. Specify duckbill valves if heavy slurries or fibrous materials are being pumped.
Refer to the Chemical Resistance Section to help determine compatibility.

Order Notes: When ordering a mini bellows model, refer to steps 1 through 3 and follow the example provided.

Example: The model number and codes for a 2-tandem pump with 1" bellows module, with EPT/EPDM elastomers and 3/8" barbed connector and a 1" bellows module with Viton ® /Fluoroelastomer O-rings and a 3/8" elbow connector, all driven by a 115V, 50/60 Hz, motor would be: 16220-011 X-112 T-003 X-116 T-008.

1. Using Chart A and B or C, select bellows module(s) and a motor RPM combination whose maximum output meets or exceeds your flow requirements. Best metering accuracy occurs when bellows modules operate at 50% or more of their maximum output. Then refer to Charts E and F to select an appropriate model number. If T-head valve body is required, please consult factory.
2. Using Chart D, select the appropriate X-code for each module's O-ring, and poppet or duckbill valve elastomers. Place largest bellows module closest to motor. Refer to example.
3. Using Tubing Connector Chart, select one T-code for each X-code chosen from Chart D. (When ordering tandem pumps, the largest bellow module is nearest the gearmotor.)