How should the mixing of two liquids with different pressures be considered?

If the pressure difference is too large, care must be taken to prevent the raw material from being poured into another tank.

The pressure in the delivery pipes for the two materials doesn’t matter; the main issue is the pressure in the tubular mixing container you mentioned. As mentioned to the original poster, one of the material transfer pipelines relies on gravity flow; therefore, the mixing container should be connected to the atmosphere, or at a pressure slightly higher than atmospheric, so that the material can flow in smoothly. Otherwise, the material in that self-flowing pipeline would definitely be pushed back.

Mixing can be done using a injector. There should be no problem in using high-pressure fluid to mix low-pressure fluid. It’s advisable to consult the manufacturer

Mix it in the pipeline; then install a pressure reducing valve before the mixing point for the high-pressure stream.

First, check valves should be installed on the two material pipelines. Secondly, the liquid pressure should be kept relatively close

In my opinion, buffer equipment should be added to ensure uniform mixing. Reducing pressure is not a good solution, as the pressure in the self-priming tank also decreases as the liquid level drops, and the pressure regulator cannot adjust its setting at any time. Adding another pump might be the proper solution.

Mixing can be achieved using a ejector. High-pressure fluid passing through an ejector pump creates a suction effect that allows low-pressure fluid to be smoothly incorporated into the high-pressure fluid

Ensuring no backflow is mainly to keep the flow unobstructed and prevent pressure buildup in the mixer; otherwise, low-pressure fluid will flow back into it. As a safety measure, high-pressure stream flow limitation (selecting an appropriate pipe diameter, and adding flow-limiting orifice plates if the pipe size is large) / low-pressure stream check valves can be considered. If there is flow control, then flow restriction is unnecessary; simply choose a control valve with an appropriate diameter and pressure difference. Last edited by RainWolf on 2009-2-12 22:08.]

The problem posed by the original poster is well-suited for mixing using a injector, which takes advantage of the kinetic energy of pressurized fluid to draw in unpressurized fluid for mixing. The device is widely used: steam vacuum pumps in distillation towers, vapor (air) pumps for water recovery, etc.

Mixing is carried out using a injector. High-pressure fluid passing through an injection pump creates a suction effect that allows low-pressure fluid to be smoothly incorporated into the high-pressure fluid. Care must be taken, as an increase in back pressure causes the injector to lose its suction power, forcing the low-pressure fluid back into another feed tank. The voltage drop issue must be discussed with the supplier to achieve the desired results.

It should be fine to first reduce the pressure of the high-pressure side a bit before mixing it with the low-pressure side. It is also mixed inside the pipeline; if check valves are installed at the inlets of the two liquids, mixing can be done directly as well

First, a check valve should be installed on the pipeline for low-pressure materials. Second, for gravity flow, it is necessary to consider from what height the flow occurs and what the height difference is. Third, measures must be taken to prevent high-pressure materials from entering the pipes carrying low-pressure materials, or to stop the flow of materials in the low-pressure pipes from moving downward. :lol

Check valves and globe valves are installed on each of the two liquid pipelines; the globe valve is used to regulate the pressure drop in the pipelines in order to balance the pressures between them, while the check valve prevents backflow.

In many factories, injectors are used as mixers, but it is generally required that the flow rate and pressure remain stable; otherwise, control becomes difficult. As many experts have said, it is advisable to consult the manufacturer. Using a mixing tank connected to the atmosphere is also a good solution. Adding a pump is not recommended as it is not economical

The issue mentioned by the original poster depends on the circumstances. For simplicity, let’s refer to liquids at normal pressure, liquids pumped, and mixed liquids as A, B, and C respectively; their pressures and flow rates are denoted as Pa, Pb, Pc, Qa, Qb, and Qc respectively. 1. When Pc is at atmospheric pressure (i.e., Pa = Pc), and A flows into the pipeline mixer due to static pressure, B can be mixed with A directly ； 2. When Pb >> Pc > Pa, and calculations show that using B as the driving medium for the ejector is sufficient to draw in A and mix it with B to form C, then an ejector can be used ； 3. When Pb>>Pc>>Pa, and it is calculated that using B as the driving medium for the injector is not sufficient to completely pump out A, or when the direct pressure difference between Pb and Pc is too small to pump out A, a pump should be used to transport A in such cases.