Vacuum Grippers

EDCO ER L-Series Coaxial Venturi Technology

The ER L-series nozzles have been specifically tuned and optimized to provide the high-flow, mid-range vacuum that a typical industrial system requires. This vacuum pump can efficiently handle a wide variety of both prous and non-porous applications at only 72 psi (5 bar) air supply.

Additional benefits of EDCO ER L-series venturis are rugged material nozzles, no internal flap valves to foul and a large nozzle throat gap that allows ingest debris to pass through and out the exhaust. When coupled with the PP or LP purge options, debris too large to pass can be expelled between cycles.

Centralized Systems

A centralized system has on "central" vacuum pump supplying all vacuum cups int he system so all cups operate at the same system vacuum level. This vacuum level is affected by the flow capacity of the vacuum pump and the aggregate system leakage. System internal volume is increased by the necessary vacuum hoses, manifolds and tubing in a centralized system. The increased volume results in a longer evacuation time for the system to attain a safe vacuum level.

Centralized vacuum pumps are necessarily oversized to provide enough extra vacuum flow capacity to overcome normal porosity and cup wear. However, instances where there is gross leakage caused by non-sealing vacuum cups due to missing or damaged work pieces, pump capacity can't overcome the leakage and system vacuum level can be reduced to the point where it is unsafe or impossible to pick up the work pieces. Interdependence of all vacuum cups in a system is not desirable, so EDCO has developed components suach as Flow Sensor Valves and Dual Flow Valves to make centralized systems perform better by limiting the flow loss from non-sealing vacuum cups.

Part quick-release, or blow-off, is accomplished by injecting a blast of compressed air through an isolation check valve and into the centralized vacuum system somewhere prior to the vacuum cups. This pulse of air quickly dissipates system vacuum. Since flow follows the path of least resistance, most of the air can flow out of the pump exhaust instead of into the vacuum cups.

Operating Pressure

Operating a vacuum generator at a lower pressure will not result in reduced energy consumption pre se. Energy usage of air-powered devices is measured by the volume flow rate of compressed air. Operating one machine device at 45 psi, for example, will not reduce the overall energy consumption of a manufacturing plant because of all the other machine devices that still require higher air pressure to function properly. The central compressed air system must be tuned to continuously provide at least the minimum air pressure required by any device in the plant.

To make direct comparisons possible, air consumption at different operating pressures must be converted to a "standard" or "naturalized" volume at standardized atmospheric conditions. For example, either 1.0 cfm (28.3 Nl/m) at 87 psi (6 bar) or 1.36 cfm (38.5 Nl/m) at 60 psi (4 bar) are equivalent to 6.9 scfm (195 Nl/m) at standard atmospheric conditions and thus equivalent compressor loads.

Compressed air systems are designed with receivers (storage tanks) that are charged with high pressure air to serve as accumlators that can supply air flow in addition to what the compressor can produce for short periods of time. During extreme peak demands, the stored high pressure air may be drawn down, or depleted, causing the delivered system pressure to dip below otpimum pressure. For this reason, industrial machines are commonly designed to operate at only 80 psi, but some plants with marginal air systems may require machines to operate at only 60 psi. Systems that are optimized to operate at reduced air pressure should include air regulators set to deliver the proper minimum design pressure otherwise air consumpion (energy costs) will be increased substantially whenever the system air pressure is higher.

Central Vacuum System

Discrete Systems

A discrete system is made up of several mini-system units. Each unit consists of a small vacuum pump coupled to a single vacuum cup so that each unit operates independently of the others. Leakage at a non-sealing cup can only affect the vacuum level of that single cup so any leakage problems are automatically isolated. This gives the overall system the best possible chance to operate reliably even with a reduced number of active cups.

An EDCO Vacuum Gripper integrates a vacuum pump and vacuum cup into one compact unit to eliminate all excess system volume so that evacuation time is minimized.

A discrete system may be split into several zones that are each controlled by separate air supply valves to allow operation of one, several or all zones as the application requirements change. All discrete units in a zone are simultaneously turned on or off via the compressed air supply, however, each mini-system unit still operates independently on the vacuum side.

Part quick-release is accomplished by blocking the pump exhaust with an air piloted piston which causes the pump air supply to flow directly into the vacuum cup because there is no other possible flow path. This positive pressure reverse flow not only provides a very fast part release but also provides a cleaning action to purge any debris that was ingested into the vacuum cup.

Rugged Shear Key Mount

Two-point mount with shear keys eliminates the possibility of pumps shifting out of position during operation. Work loads are efficiently and directly transferred to the mounting profile so that the mounting screws carry only tensile loads.

Simple Installation & Flexible Positioning

Vacuum Grippers mount easily to extrusion profiles having 5/16" (8 mm) t-slots so they can easily be repositioned to accomodate changing handling conditions. The two-point mount provides security and rigidity.

Positive Pressure Purge (PP)

Air pressure supplied to the venturi is diverted to the vacuum port by blocking the ventturi exhaust with a piston operated by a pilot pressure signal. Push-in tube connector swivel accepts 5/32 (4 mm) tubing. Tool separation movement must begin immediately (no dwell) when purge signal is initiated to prevent excessive positive pressure inside vacuum cups due to forces pressing the tool onto the work surface. Do not use PP option with vacuum switches due to the limited over-pressure capability of switches.

Limited Pressure Purge (LP)

The LP option is similar to the PP option except it includes an orifice in the purge piston. Purge air flow is not as robust as with the PP option, but air pressure is limited inside the vacuum cup.