This article is about Evaluating the offer of a metering pump is an important part of the procurement process. It is necessary to ensure that the pump model offered is developed by the vendor and is in operation in at least one installation. In addition, it is important to check technical specifications, plunger/piston details, variable-capacity adjustment method, specific requirements, gear and gearbox details, diaphragm pump compatibility and safety valves. This article provides an overview of what needs to be considered while evaluating the offer of a metering pump.
Technical Bid Evaluation for Metering Pump
- Evaluating the Offer
When evaluating the offer of a metering pump, it is important to check that the model offered is a developed one, and is in operation in at least one installation. Additionally, the type of the pump, i.e. plunger or diaphragm (single, double, sandwich) must be checked as per technical specification. It is also important to check the turndown ratio of the pump. - Plunger/Piston Details
When evaluating the offer of a metering pump, it is important to check the plunger/piston details such as plunger diameter, stroke length, and strokes per minute. It should also be ensured that the rated capacity furnished by the vendor is correct and matches the quoted volumetric efficiency. For packed plunger pumps, it is recommended to have strokes per minute less than 100 for better wear and tear. Furthermore, the plunger should be hardened and the average linear speed at the maximum capacity should not exceed 1.4 m/s. - Variable-capacity Adjustment Method
The variable-capacity adjustment method should be checked as per technical specification. If a remote operation is required, the details of the servomotor pneumatic positioned and the operating scheme should be furnished by the vendor. - Specific Requirements
When evaluating the offer of a metering pump, it is important to check specific requirements such as cooling, heating as per specification. Additionally, the NPSHA should be specified in the pump inquiry specification without considering the acceleration head (based on suction line size and length). NPSHR quoted by a vendor should include acceleration head. - Gear and Gearbox Details
The gear and gearbox details should be checked. The gearbox service factor must be at least 1.5 for continuous operation. The manufacturer should be furnished the maximum power rating for the gear. Gears should be from a reputed make. The gear ratio should be checked with respect to motor speed. - Diaphragm Pump Compatibility
In the case of a diaphragm pump, the compatibility of diaphragm material should be checked for suitability of process fluid. Sandwich-type diaphragm-type pumps should be checked for vendor’s reference, if specified. - Safety Valves
Process side safety valve should be externally mounted and should have flanged connections (applies mainly for plunger type). Externally mounted safety valves should be supplied from approved vendors only.