Needle Valve / Pump System

Use a slurry throttling valve, or pinch valve.

Why have a bypass valve at all (if that's what this is)? How about a constant-torque-type VFD to control the motor so that steady pressure is maintained for varying flow rates?

I have looked in the slurry valve and pinch valve, however, i can not find any valve that will got up 1500 PSI, they are usually around 150 or so PSI.

I had also looked into orifice plates and fluid reduction adapters like sand blasting nozzles, however, there are too many unknown variables to correctly design something that would work.

The only other thing i can think of is coating the steam and seat of a needle valve with chrome that i can get around 62C but that is a lot of time and machining to achieve this.

1- is it in a drilling unit or in the preparation of the drilling mud out of the drilling site ?

2- why do you need a needle ? The drilling installations I know do not have any bypass only a safety valve to open to tank in case of clogging in the circuit. The pressure is given by the tubing length and by the nozzles in the drilling tool and of course by the coming back to surface in the space between drilling tube and bore wall. usually the mud pumps have a gear box to change flow according to requirements but no bypass valve which leaks continuously. I have the feeling that in your circuit something is wrong.

In earth drilling there is NO need for a PRESSURE but for a FLOW to take the stone parts from under the tool (mostly by mud jets), cool the tool cutting edges (and bearings if it has rolling heads) and transport parts to surface. Pressure is a result of flow.

That is true, in the true application of the drill there is no need for a needle value or restriction of flow to increase pressure. However, I am trying to test a component of the drilling process and i need to test it under pressure to check for leaks and life of the component. I am not worried about flow through the system just the pressure; i only need a little to make sure the seal stay cool.

Then you do not need a pump if only the seal is to be checked. You can make a static test with a hand pump and water for instance. Of course if you do not check a rotating seal. I would suggest you give more informations in order to get a recommendation how to optimize your test.

Your needle wears mostly because of the abrasive effect of mud. The only solution is to use a steel very high treated ( 62 HRc for instance) AND coat it with a wolfram (tungsten) carbide layer.

The hard basic material is needed to avoiding local deformations due to impacts and the layer is resistant to abrasive wear due to carried particles.

An other solution is to have more resistors (needles) in series so that openings are bigger for each one and flow speed lower thus reducing impact and wear. Try with at least 3 (better 4 or even 5) in series opened so that pressure drops are equal. The lower the flow velocity the lower the wear.

I know how drilling works since many years ago I was involved in the design and manufacturing of earth drilling rigs, a family, for geological research drilling depth from 25 mm to 2000m.

Nick,

Thank you, i didn't think of using several needles to help reduce wear. Our plan was to modify a needle just like you described.

The pumping system that we have is an open loop system, that a 3 piston pump (supplied by customer), pump mud through a pulse dampener, then through a unloader valve, then to our product (rotating union) back through pressure transducer, (for safety), then through a needle valve (to build back pressure) and then back to tank (atm pressure).

Just for FYI,

There is a company out there that makes a chock valve with ceramic seat and steam that can with stand pressure from 2000 to 20000 PSI it is called "Houston Oil Field Equipment"

Thanks for all your help.