Pressure Intensifiers

Harwood has made pressure intensifiers for service to 200,000 psi since 1948. The predominant use for this equipment has been for testing and isostatic compactions, which allow the use of relatively non-aggressive chemicals as the high pressure fluid. This, in turn, has allowed Harwood to use martensitic alloy steel in our standard intensifiers. If it is necessary to deal with an aggressive chemical, contact Harwood – there are cost-effective solutions to the problem.

Intensifier Design Characteristics

Harwood intensifiers are characterized by relatively long strokes and large piston diameters. At least three advantages result: for a specified delivery volume this means fewer strokes and fewer applications of stress, hence less metal fatigue and longer life of all components. With fewer reversals of the pistons, the wear of moving seals is minimized. The longer the stroke, the less proportionately is the unswept volume – the volume between the end of the piston travel and the check valves outside the cylinder head – consequently the higher the efficiency.


The construction of the Harwood intensifier is such that there is no contamination between the high pressure and drive pressure fluids.

Intensifier Module

DA4 Intensifiers Module

We offer the bare intensifier; however, it is recommended that the purchase of the intensifier module be considered, especially for double-acting intensifiers. To the right is a picture of a typical DA-4 module, including a strain gage cell transducer and a rupture tube safety assembly.


The module includes the intensifier, a high pressure check valve manifold, and 4-way directional control valve mounted on a rugged steel frame – leaving the customer with only the requirement to fit the hydraulic drive to the module to get a complete system. The standard hydraulic drive is 2,000 psi.

Single-Acting IntensifiersSingle Acting Intensifiers Schematic

For situations where the intended use is for something like small compactions and fatigue machines, a single acting intensifier has the advantage of increased packing life and significantly easier maintenance as opposed to a double-acting intensifier. For applications where the desired pressure can be achieved in a single stroke it is sensible to use an SA over a DA as it is less expensive, less of a hassle to change packings, and hence less down time for maintenance.

Double-Acting IntensifiersDouble Acting Intensifiers Schematic

Harwood’s double-acting intensifiers provide increased efficiency in pumping by utilizing two separate high pressure pistons powered by opposite strokes of a single low pressure piston. Each traverse of the piston assembly acts as a filling stroke for one end of the intensifier while providing compressive power for the opposite end.  DA14 BareNot only is wasted time in intake stroke eliminated; there is a considerable gain in uniformity of high pressure output over that of the single-acting intensifier.

The picture to the right shows a bare DA-14 intensifier for 200,000 psi sitting on a frame.

Both single and double-acting intensifiers in multiple arrangements may be synchronized to provide high pressure output free of pressure fluctuations with Harwood’s patented “Pipless Pumping Systems”.

Intensifier Models

The tables below show information on some of the intensifier models that we offer. Other sizes that are not listed are available as well. There are slight but critical differences in the internal details of a liquid intensifier verses a gas intensifier, however, intensifier models discussed here apply to both liquid and gas. Intensifiers for lower pressures with larger displacements are available. Contact us directly for details.


DA 2.5 –5 –.437 –50k0.75
DA 2.5 –5 –.500 –40k0.98
DA 2.5 –5 –.687 –20k1.86
DA 2.5 –5 –1.000 –10k3.93
DA 4 –6 –.687 –60K2.23
DA 4 –6 –.750 –50K2.65
DA 4 –6 –.875 –40 K3.61
DA 4 –6 –1.125 –20K5.95
DA 4 –6 –1.625 –10K12.45
DA 7 –8 –.938 –100K5.55
DA 7 –8 –1.063 –75K7.1
DA 7 –8 –1.188 –60K8.86
DA 7 –8 –1.250 –50K9.84
DA 7 –8 –1.375 –40K11.9
DA 7 –8 –1.625 –30K16.6
DA 7 –8 –1.750 –25K19.25
DA 7 –8 –2.000 –20K25.15
DA 7 –8 –2.375 –15K35.5
DA 7 –8 –2.875 –10K52
DA 7 –8 –4.125 –5K106.9
DA 10 –6 –.875FB –200K3.6
DA 10 –8 –1.063FB –150K7.1
DA 10 –8 –1.25B –100K9.84
DA 10 –10 –1.50B –75K7.7
DA 10 –10 –1.875B –50K27.6
DA 10 –10 –4.00B –10K125.6
DA 14 –8 –1.250FB –200K9.84
DA 14 –12 –1.375FB –150K17.76
DA 14 –12 –1.750B –100K28.8
DA 14 –18 –2.500B –50K88.38
DA 14 –18 –3.313B –30K143.64
DA 14 –18 –3.875B –20K212.4


SA 2.5 –5 –.438 –50k0.75
SA 2.5 –5 –.500 –40k0.98
SA 2.5 –5 –.563 –30k1.24
SA 2.5 –5 –.688 –20K1.86
SA 2.5 –5 –1.000 –10K3.92
SA 4 –6 –.688 –60K2.23
SA 4 –6 –.750 –50K2.65
SA 4 –6 –.875 –40K3.61
SA 4 –6 –1.125 –20K5.95
SA 4 –6 –1.625 –10K12.45
SA 7 –6 –.750 –150K2.65
SA 7 –6 –0.938 –100K4.15
SA 7 –8 –1.063 –75K7.1
SA 7 –8 –1.188 –60K8.86
SA 7 –8 –1.250 –50K9.84
SA 7 –8 –2.000 –20K25.15
SA 7 –8 –2.875 –10K52
SA 10 –6 –.875 –200K3.6
SA 10 –8 –1.063 –150K7.09
SA 10 –8 –1.250 –100K9.81
SA 10 –10 –1.500 –75K17.67
SA 10 –10 –1.875 –50K27.61
SA 10 –10 –4.000 –10K125.66
SA 14 –8 –1.250 –200K9.81
SA 14 –12 –1.500 –150K21.2
SA 14 –12 –1.875 –100K33.13
SA 14 –12 –2.500 –50K58.9
SA 14 –12 –4.000 –20K150.79


Harwood Series 2.5 Intensifiers

Our standard laboratory sized intensifiers. Originally designed for use with small liquid systems, they have occasionally been used for the last stage of gas compressors. There are a few models to choose from, all with varying pressure ratings and displacements – usually sufficient for laboratory type work. Information on our larger intensifiers can be found here.

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