Is the lubricating oil the same for reciprocating pumps and centrifugal pumps?

1. First, consider the lubrication areas: Reciprocating pumps generally use worm gear drives, and the lubricant used is usually 220# gear oil (suitable for high-load worm gear drives as well as industrial gears that are subject to high speeds, impact loads, and heavy loads). Some reciprocating pumps employ diaphragm piston pumps, in which the pistons are driven by 32# hydraulic oil. 2. Centrifugal pumps are generally used to lubricate bearings, and 46# machine oil is usually sufficient

Yes, is it harmful to use 46# mechanical oil over the long term in a diaphragm plunger pump?

It’s best not to, as the use of lubricant for equipment is related to factors such as speed and material. Check the technical specifications of the equipment; if lubrication is required, as long as the viscosity, flash point, acid value, and other properties of the oil you use meet the specified requirements, there should be no problems.

The lubricating oil used for the centrifugal pumps in our workshop is N46# general machine tool oil, while 24# cylinder oil is used for the steam reciprocating pumps.

My ordinary centrifugal pumps and reciprocating pumps both use HL46#, with no problems.

Reciprocating pump: A reciprocating pump is a type of positive-displacement pump that relies on the reciprocating motion of a piston within the pump cylinder to change the working volume, thereby achieving the purpose of transporting liquids. The working principle of a reciprocating pump will now be illustrated using a piston type as an example. A piston pump mainly uses the reciprocating motion of a piston within the pump cylinder to draw in and discharge liquid. As the piston begins to move from its far left position toward the right, the volume of the working chamber gradually increases, causing the pressure inside to drop. The fluid then pushes open the suction valve and enters the space created by the moving piston, until the piston reaches its far right position. This process constitutes the suction phase of the pump. When the piston moves from the right end to the left end, the fluid filling the pump is compressed, which closes the suction valve and opens the discharge valve to allow the fluid to be expelled; this process is known as the compression stroke of the pump. As the piston moves back and forth continuously, the suction and compression processes of the pump alternate continuously. The characteristics of this pump are: the pump pressure can be infinitely high, the flow rate is independent of pressure, it has self-priming capability, and the flow rate is uneven. This pump is suitable for infusion systems with low flow rates and high pressures. The areas that require lubrication are mainly those with moving parts relative to each other. 1. Piston: The piston is equipped with gas rings and oil rings, which experience friction against the cylinder walls and therefore require lubrication. No matter how good the gas rings and oil rings are at sealing, it is inevitable that a certain amount of lubricating oil – even if it’s just a small quantity – will be consumed, and therefore it needs to be replenished. Lubricant: Lubricants not only serve a lubricating function but also perform tasks such as sealing and cooling. Sealing and lubrication: of course, a higher viscosity is better, but for cooling purposes, a lower viscosity is required, along with good fluidity and low circulation resistance. The manufacturer’s recommendations are mostly approximate, as they are not aware of the specific operating conditions. Mostly 46/68/100/150, etc. 2. Crankshaft and connecting rod: The crankshaft and connecting rod are equipped with bearings and bushings, which need to be lubricated. Lubricant: When the pressure is high and the load on moving parts is great, a lubricant with higher viscosity is required. As required, size 150 is preferred. Why is it so complicated? How exactly should one choose the viscosity of lubricating oil? 1. Consider the operating temperature of the pump. Consider the ambient temperature and the temperature of the pumped substance. Regarding ambient temperature, large pumps in northern regions are usually equipped with heating devices to prevent the lubricant from becoming too viscous in winter; this makes it difficult to pump the lubricant at startup. 85% of all wear and damage occurs during startup, due to the lack of lubricant on the surfaces of the lubricated components. The temperature is too high, causing the viscosity of the lubricant to decrease. When the viscosity is too low, lubrication is inadequate, which leads to increased wear; therefore, cooling is necessary. At higher temperatures, high-temperature lubricants must be used; otherwise, carbon deposits and similar issues are likely to occur. In summary, for reciprocating pumps operating at temperatures between 0 and 30 degrees, mineral oil grade 46 is sufficient. For 0-60 degrees, grade 68 is ideal; for 0-80 degrees, grades 100/150 are the best choice. -For temperatures between 20-100 degrees, it is best to use fully synthetic lubricants of grades 68/100/150. It has better high and low temperature performance. 2. Check the pressure of the pumped material. With high pressure and high load, a higher viscosity value should be chosen. In special cases, cylinder lubricant with grade 680 can also be chosen.

Centrifugal pump lubrication mainly concerns the bearings. The main factors to consider are: 1. Temperature: If the temperature is above 100 degrees, use synthetic lubricant grade 150. It can last from 6 to 1 year, or even 2 to 3 years without needing to be replaced. Minerals should be replaced every 6 months at the latest, and issues should also be checked. 2. Rotational speed: For applications with low rotational speeds and relatively low temperatures, grease can be used (dry oil lubrication). Generally, in applications with high speeds and high temperatures, lubricating oil is used, as its ability to dissipate heat is a key factor to consider. For centrifugal fans/compressors imported from abroad, manufacturers recommend fully synthetic lubricants rated 150 or 46. Fully synthetic lubricants offer excellent high and low-temperature performance. **The types of lubricants have been simplified. High temperature, number 150. The temperature isn’t too high; it’s 46 degrees. 3. Fluid or gas. Consider the corrosivity, and pay special attention to the components of the lubricating oil.

For centrifugal pumps, using No. 46 is sufficient; it can also be used for reciprocating pumps, but it’s better to follow the instructions regarding the type of fluid to use.

Viscosity, flash point, and acid value are the key factors determining lubricants, and they have nothing to do with the type of pump

The working principle of a reciprocating pump is that the crankshaft drives the piston rod to move back and forth. It is mainly to lubricate the bearing shells. And centrifugal pumps have different requirements for lubricating oil regarding bearings, right?