Help, considerations for selecting a pump

Choosing a brand is actually more important. Every manufacturer has product brochures and instruction manuals. Based on the parameters above, select those that suit you, and then communicate with the manufacturer to confirm them. For reference.

Physical properties of the material: viscosity, specific gravity, temperature. The chemical properties of the material, whether it is an organic or inorganic solution, and its corrosiveness. Required head, flow rate. There are also the operating conditions at the location where the pump is used, such as altitude and ambient temperature.

I’ve learned it.* After fully understanding the operating conditions mentioned above, the first step is to determine the type of pump to choose, and then it is necessary to understand the owner’s requirements regarding the desired performance level and the brand of the pump. Pumps are mechanical and electrical devices; in some projects, they are included in the tax rebate list (such as foreign investments, external investments, and **sovereign loan projects, etc.**). As mentioned on the third floor, elevation can also be important at times—the pump might still be fine; generally, it’s sufficient to pay attention to changes in the net positive suction head. The air supply system is affected more severely. Incidentally, it wasn’t the altitude at the time; rather, it was the high temperatures in tropical regions that led to insufficient oxygen supply during inhalation……

It is recommended to fill in the information accurately according to the API610 data sheet. First of all, I don’t think the specifications of centrifugal pumps can be too precise or detailed in terms of operating conditions. There are often situations that are unimportant to the buyer, yet these situations can have a significant impact on the ultimate lifespan of the equipment. I will give a specific example: I once noticed the specifications of a common vertical wet mine pump, which were very detailed in every aspect, merely indicating the range of its operating capacity. It can be inferred that the pump will operate at its designed capacity or approximately at its designed capacity. After the pump was installed, shortly after its first operation, severe shaft vibration was detected, which impaired the proper functioning of the packing in the stuffing box. The pump shaft broke below the impeller just 2 months after its first operation. Surveys show that the pump operates at 25% to 10% of its design conditions for 80% of the time. This special type of pump possesses a decisive radial thrust within this capacity range, and is not suitable for operation outside the general range of 75% to 120% of the rated flow rate. If the manufacturer is aware of the actual operating conditions, it is easy to select a pump suitable for those conditions; this results in low costs for the user and helps avoid a range of problems. Although we cannot address all the information in too much detail and inform potential bidders, it is best to list some basic information that should be specified in the specifications: 1. What is the nature of the liquid to be pumped? a. Is it fresh water or saltwater? ； Acidic or alkaline ； Oil, gasoline, or mud ； Or something else? b. Cold or hot? If it’s hot, what is the temperature? The saturated vapor pressure of a liquid? c. What is its specific gravity? d. Is it viscous or non-viscous? e. Is it clear, free of suspended particles or dirt, sand, and grit? If it is the latter, what are the size and properties of the solids, and do they have an abrasive nature? If the liquid is pulp-like, what is its consistency expressed as a percentage or in kilograms per cubic meter of liquid? What is suspended matter? f. Chemical analysis results, pH value, etc.? What changes are expected in this analysis? 2. What are the minimum and maximum flow rates of the liquid that the pump needs to transport? 3. What are the inhalation conditions? Is self-priming capability required? What is the suction height (pump inlet conditions)? What changes are expected under these conditions? 4. What are the export conditions? a. What is static head? Is it a constant or a variable? b. What is a friction head? c. Considering the specific gravity of the pumped medium, what is the maximum discharge pressure? 5. Is the pump continuous or intermittent? 6. Is the pump installed horizontally or vertically? If it’s the latter, a. In a wet pit? b. Still in the dry pit? 7. What powers the drive pump? What are the characteristics of this type of drive? 8. What are the space, weight, or shipping restrictions? 9. Where is the installation location? This should include altitude, geographical location and its impact on the recommended spare parts, as well as the surrounding environment that may affect accessibility. 10. Are there any special requirements or preferred options marked regarding the design, structure, or performance of the pump? This is the last item, which can easily become a highly controversial issue. I think these special requirements or preferences should be listed, but buyers should avoid being too rigid toward manufacturers whose quotes deviate from these requirements or preferences, provided that reasonable explanations are given for such deviations. Please keep in mind that some of these preferences may be based on a lack of knowledge about the most modern practices or designs. On the other hand, they may stem from experience in operating pumps under the same conditions that new pumps must meet. Many valuable pieces of information can be provided to pump manufacturers, which will enable them to supply this type of equipment that offers the longest and most reliable service. But I firmly believe that clients’ recommendations should be limited to their experience operating pumps under similar conditions, so as to prevent their preferences from leading to the purchase of highly specialized equipment. It is advantageous to use the manufacturer’s standard structure whenever possible, considering both the initial cost and the spare parts needed for subsequent repairs. It is certain that in some cases, clients may be forced to write very \"compact\" specifications. For example, municipal or federal agencies are like that. The legal issues that arise when these organizations purchase any equipment require the use of such standards, so as to prevent them from being forced to buy equipment that does not meet the requirements. Simply because the bidder’s price is the lowest among all bidders. But when this is not the case, such as when private enterprises are not forced to purchase at the lowest price, there is an excessive tendency to restrict possible products to a very narrow range and to require special construction methods and materials; if no special tests are necessary, the most economical equipment is not chosen.