Enerpac Hydraulic Air Pumps

The differences in oil capacity and reservoir volume determine the size of the hydraulic cylinders you can safely run with each pump:

• Enerpac PA133 Air Pump: Engineered with a usable oil capacity of 36 cubic inches (589 cm³). It delivers an oil flow rate of 80 in³/min at no load and 8 in³/min (0.13 L/min) at its maximum 10,000 PSI pressure limit. It is ideal for driving small, low-profile cylinders and compact spreaders.
• Enerpac PA1150 Air Pump: Features a larger reservoir with a usable oil capacity of 80 cubic inches (1,311 cm³). It shares the identical oil flow rate of 8 in³/min (0.13 L/min) at 10,000 PSI, but its expanded reservoir capacity allows it to drive larger RC-Series cylinders up to 50-ton capacities.

To achieve a full 10,000 PSI hydraulic output pressure, you must feed the pump with a clean, regulated compressed air supply that meets these parameters:

• Air Pressure Range: Requires an incoming air pressure between 60 to 120 PSI (4.1 to 8.3 bar). If your air supply drops below 60 PSI, the pump will lose its high-pressure lifting speed and may stall under heavy loads.
• Air Consumption: Operates at a consumption rate of approximately 9 to 10 SCFM (255 to 283 L/min) under full load. Running these pumps on small, portable carry-tank compressors can cause the compressor to run continuously, which may lead to pressure drops.

No, standard PA-Series pumps (like the PA133 and PA1150) are designed exclusively for single-acting hydraulic cylinders:

• Single-Acting Compatibility: These pumps feature a single hydraulic outlet port and are built to advance and hold cylinders that utilize an internal spring to retract the plunger.
• Double-Acting Systems: Double-acting cylinders require two separate hydraulic lines (one to advance and one to retract). To operate these cylinders, you must utilize an Enerpac pump equipped with a 4-way control valve (such as the PAM-Series or custom electric/gas pump configurations) to manage the dual-line flow.

Enerpac PA-Series pumps feature a dual-stage safety valve configuration. The primary safety mechanism is an internal, factory-set pressure relief valve. If the cylinder plunger reaches the end of its stroke and the operator continues to press the advance foot pedal, the hydraulic system pressure will spike. The moment the internal sensor registers a pressure threshold of approximately 10,000 PSI (700 bar), the relief valve opens, instantly routing the pressurized oil back into the pump reservoir. This prevents pressure spikes that can crack pump manifolds, burst hoses, or damage the cylinder seals.

The physical orientation limit of a hydraulic pump depends entirely on its reservoir venting design:

• Standard Vented Pumps: Require a small air vent at the top of the reservoir to prevent a vacuum from forming as oil is pumped out. If these pumps are turned sideways or upside down, the oil will leak out of the vent.
• Enerpac PA133 (Bladder Reservoir): Utilizes a fully sealed, flexible internal bladder system. As oil is pumped out of the bladder, the bladder collapses naturally without requiring a vacuum vent. This sealed design prevents oil from leaking and ensures reliable operation in vertical, horizontal, or inverted orientations.

The high-pressure generation is based on the physics of force distribution across different surface areas ($F = P \times A$):

• The pump contains an internal air piston with a large surface area (e.g., 10 square inches) that is driven by 100 PSI of compressed air. This generates a total force of 1,000 lbs.
• This force is transferred directly through a steel shaft to a small hydraulic plunger with a tiny surface area (e.g., 0.1 square inches).
• Concentrating that 1,000 lbs of force onto the tiny 0.1 square inch surface area multiplies the fluid pressure to 10,000 PSI, allowing you to drive heavy-duty cylinders with standard shop air.

Because these tools run on compressed air, they are exposed to water vapor, rust scale, and dirt traveling through your jobsite air lines. To protect your investment:

• Inlet Lubrication: Add 2 to 3 drops of light air-tool oil directly into the pump's air inlet port weekly to keep the internal air motor lubricated and prevent sticky valves.
• Oil Inspections: Periodically check the hydraulic oil level and color. If the oil appears milky or dark, drain the reservoir and refill it with clean, genuine Enerpac HF-Series hydraulic oil. Never use automotive brake fluid or standard jack oil, as they will degrade the pump's synthetic seals.
• Air Filtration: Always run an inline filter/regulator/lubricator (FRL) unit on your compressor lines to block moisture and dirt before they reach the pump.

As an authorized stocking commercial trade distributor and certified Enerpac service depot, Ohio Power Tool carries a comprehensive portfolio of high-pressure hydraulics. We maintain deep regional field stock on Enerpac PA133 and PA1150 air pumps, RC-Series single-acting cylinders, 10,000 PSI high-flow couplers (C604), steel-braided hydraulic hoses, and premium HF-series hydraulic fluid to ensure your structural construction, rigging, and plant maintenance crews maintain peak capacity.