Coolant pump selection

Are the machines in series or parallel?

What are these machines? What resistance will they give to the coolant?

I suspect you are saying they are in series and if so you will need to tell us more about the machines. What size pipe is supplying the machines?

No info no answers I'm afraid.

I think you need to be very careful.

If you pump to even 2 outlets and one is physically lower than the other, the low one will get the majority of the flow, similarly if one outlet has a smaller orifice or is further away...Unless the pump has vastly greater capacity than is needed and you can pressurise a common rail I think you will have problems guaranteeing an even flow to all outlets.

I am happy to be wrong on this one, I have my fire proof underwear at the ready!

I am assuming that this is a machine 'cooling' system in that the fluid is passing through passages of the machines or heat exchangers (incidentally, what kind of machines are these?).

If the system is in series, the flow resistance will be that of one machine times 5 plus the additional piping and regardless of what sort of pump you use, what goes in will come out the last machine, there will just be a progressive pressure drop through the system.

The problem with the series arrangement is that the heat removal from each machine will increase the coolant fluid temperature delivered to the next machine and thus, the machines on the end of the series will likely not be cooled effectively because of the ΔT between the coolant and what's being cooled. Unless the machines were designed to be cooled in series (which is doubtful) you must arrange them in parallel.

In a parallel arrangement, the coolant would be supplied to each machine from a common manifold or header that is sized such that it can supply all 5 machines as desired, plus a marginal excess for resistance and deterioration/rust through time. (bigger is better) Each machines' supply is tapped off of the manifold with full flow service valve.

The pump is specified by your total requirements in flow (number of machines) at the pressure required (resistance to be overcome) to deliver it. I would size the pump at 20% greater than required capacity and control that excess with a regulator via recirculation or such.

The best way to accurately control the flow to each unit would be with a regulating valve (press., temp., flow, etc.) at the outlet of each unit. They could be accurately set up and or monitored with a flow meter.

There is a 'thing' termed a proportionator that I can't find just now via Google but basically it is a geared mechanical setup that has a set of chambers similar to gear pumps, and the flow through each is regulated by each other because they are all mechanically tied together. This was utilised to raise grain silos with 8 or more hydraulic rams under the silo, but one hydraulic pump, and to keep the flow rate equal to each ram to prevent tilting. the problem is that if you rupture one line, all the flow will go there and starve the other machines.

Others reading this will probably 'clean this up' and reply with a real answer knowing what device I'm speaking about . . . . I just can't remember all the details as it was 7 years ago I bought one.

Provide a continuous loop supply/return piping system (maintain a constant pressure in the loop by having a pressure sustaining valve on the return portion of the loop). Put flow control valves on the coolant inlet on each machine (this provides the exact flow you need at each machine).

You will want a hydropneumatic tank in the system for thermal expansion of the coolant.

Have variable speed motors on the pumps. With a flow of 300 LPM I would look into a centrifugal pump.

I wouldn't try to save money putting in a cooling system that won't work very well. A slightly overheated machine (of any kind) wears out faster and requires more maintenance.

If u r using all the machines at the same time, then it is better to have coolant pump supply in parallel. In this way all machines will get the flow and the same inlet temp. However, u should try to install the coolant supply line in the manner like comb so the fluid gets distributed evenly. The header pressure should be designed like a fire hydrant which maintains same pressure whether u open the valve of the lower floor (consider lower machine) or the higher floor (consider higher m/c).

Contact M/s. Grundfos pumps which are in Chennai, south India and have pumps for the similar application.

Is the coolant cooling the machine or is it lubricant/coolant for a cutting/milling tool?

I had assumed the latter.