Custom Flow Control by JM Harwood

JM Harwood’s flow restrictors, flow orifices, and orifice plates provide a precise and reliable method of metering gas and liquids, generating back pressure, and measuring flow.

Press fits, threaded fits, expansions fits, tube, flare, and practically any mechanical form factor needed.  JM Harwood will precisely meter any flow rate you need (large or small) at practically any pressure.  All flow restrictors, flow orifices, and orifice plates are calibrated traceable to NIST standards unless otherwise specified.

Flow Restrictors: Orifices vs Porous Media

flow-restrictor-jmharwoodThe overall purpose of the flow restrictor or flow orifice is to precisely meter the flow at a given pressure. Some flow restrictors use porous metal to restrict flow and generate back pressure.  The rationale for using a porous media is that it is less likely to clog than a single or multiple orifice flow restrictor.  Like many engineering applications, this is true under certain circumstances and not in others.

Any flow restrictor (porous or orifice) will clog unless adequate filtration is provided upstream of the device.  A porous media provides a multitude of very small passages where as a single flow orifice provides only one big passage.  Consequently, a porous media will be clogged by smaller particles, but it will gracefully degrade over a period of time.  By contrast, a single orifice flow meter can handle larger particulates but will degrade rapidly if it encounters a particle that is too large.

There are circumstances when it is beneficial to spread the desired pressure drop across multiple flow orifices.  One such scenario is when one needs to meter very low flow rates at very high pressures.  Under such a circumstance, it may not be practical to accomplish the entire pressure drop in a single orifice.  Another scenario is when one desires less filtration.  By spreading or reducing the pressure drop at any given flow orifice, a larger orifice can be used.

JM Harwood recommends using a separate filter upstream of the flow restrictor or flow orifice.  However if you need an integrated filter, please indicate as such in the comments section of the form below.

Flange Plate Flow Orifices

flow-orifice-flange-plateFlow orifices come in a variety of shapes and sizes.  Like flow restrictors, the overall purpose is to precisely meter the flow at a given pressure.  One popular choice is to clamp an orifice between pipe flanges.

JMHarwood designs flow orifices for ANSI flanges at any pressure and flow rate.  The standard low pressure orifice plates are 1/8-inch thick.  Thicker plates are available for higher pressures.  JMHarwood often conducts Finite Element Analysis (FEA) on high pressure plates to verify structural integrity.  When needed, an orifice can be incorporated directly into the flange.

For space constrained applications in which a flow orifice is immediately downstream of an elbow or other flow obstructions, JM Harwood also designs flow conditioners.  Flow conditioners are added upstream of a flow orifice to improve its accuracy by eliminating the flow swirl created by an obstruction and ensuring a uniform flow profile.

Pipe Fittings and Other Flow Orifices

Pipe nipples, pipe couplers, unions, tube fittings, and any standard thread.  JMHarwood designs flow orifices and restrictors in a variety of standard form factors.  Any shape, pressure, or flow.  Gas or liquid.  JMHarwood provides the solutions that you cannot find anywhere else.

Pipe-Nipple Coupler Fittings
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