3/4 HP ambient air pump for Allegro low pressure air supply respirator, no 9821.


Return conditions : No returnable if used. For more information about our return policy, please refer to the "Orders and Returns" link on the home page

This air source is an integral part of a low-pressure air respirator system from the manufacturer Allegro. The pump is designed to transfer respirable air from an uncontaminated area to a worker requiring supplied air respirator. The reasons for using this type of system are many. The most popular is certainly the application of paint containing isocyanates by a worker wearing a beard. This is the perfect model if you need to use a hood for a single worker. 

Allegro manufacturer code: 9821 and model number: A-750. 

This pump is powerful enough to provide air (10 cfm) to a person with a hood or two people with half-masks or full-face masks. The maximum allowable hose length is 100 feet. This pump plugs into a standard power outlet, eliminating the need for special wiring and electrical compatibility issues. In addition, it can be easily transported from one job site to another. 

This pump allows several configurations of facial parts and hoses.

  • One Worker with a half mask (RA9920) and a 50 or 100 feet hose.
  • One Worker with a full-face mask (RA9901) and a 50 or 100 foot hose
  • One Worker with a hood (RA9910) and a 50-foot hose, see all (RA9220)
  • One Worker with a hood (RA9910) and a 100-foot hose
  • Two Worker with two half-masks and two 50-foot hoses, see all (RA92052)
  • Two Worker with two half-masks and two 100-foot hoses
  • Two Worker with two full-face masks and two 50-foot hoses, see all (RA92002)
  • Two Worker with two face masks and two 100-foot hoses 

Specific feature of the pump:

Outside part:

  • Rigid metal base and housing
  • Brass and galvanized steel plumbing
  • Quick-connect OBAC fitting
  • Adjustable brass pressure relief valve
  • Steel handle
  • Pump painted with blue powder coating:
  • Weight 53 lbs (24 kg)

Motor part:

  • 3/4 HP (horsepower) UL approved.
  • Maximum power: 10 cubic feet per minute. (0–16.99 m3/hr)
  • Engine type: Oil less, rotary vane
  • Carbon rotating vanes (4 units/replaceable) (5.0 cm [2 "] x 3.8 cm [1.5”] x 0.55 cm [0.219”]).
  • Inlet filter: 50 microns felt material with a metal grid inlet filter housing.
  • Exhaust filter: 0.3 Micron HEPA
  • Pressure gauge: 2 " (5.08 cm) in diameter, steel housing (0–15 psi [0–1.03 bar])
  • Pressure: 0.14 to 0.83 bar (2 to 12 psi) working (maximum of 15 psi [1.03 bar])
  • Performance: 0–10 CFM (0–16.99 m3/h) at 60 Hz (adjusted via a pressure relief valve) 

Other features:

  • Sound level: at the pump: 90 dB at 6 feet (1.82 m): 74 dB at 10 feet (3.04 m): 72 dB
  • Temperature range: 0 ° C to 40 ° C (32 ° F to 104 ° F)
  • Volts: 115 V/230 V AC, single phase: 1725 rpm at 60 Hz /
  • Current draw (9821): 115 V 9.05A/230 V 4.6A @ 60 Hz
  • Cord: 6 ’(1.83 m) 16/3 AWG SJTW with built-in on/off switch plug: NEMA built-in 5–15

In order not to damage the pump, it is recommended to fix the hose and the face part before starting it. Replace the inlet filter (RA9700-01) and exhaust filter (RA9700-02) after 200 hours of use. Replace carbon vanes (RA9700-51S) around 400 to 500 hours of use.

The ambient air pump must not be used with a generator. The air inlet of the pump must be located to ensure breathable air at all times. It is essential to check the associated level of risk when using it. The manufacturer has designed its products for environments with contaminant concentrations that do not exceed the limit causing immediate death.

If you need to get breathing air beyond the pump installation, there is a 50 ’hose with adapters (RA9700-65) for this case. Also take care to have at hand the usual spare parts such as: the inlet filter (RA9700-01), the exhaust filter (RA9700-02) and why not a set of vanes (RA9700-51S). Please note that these items are available on special order only, the lead time may vary from 2 to 3 weeks.

Type of productSafety equipment
Main categoryPersonal protection
Sub categoryRespiratory protection
Sub sub categoryAllegro low pressure air-supplied respirators
Name of the productAllegro low pressure ambient air pump
Product codeRA9821
Approved/CertifiedMeets NIOSH
ManufacturerAllegro industries
Country of originUnited State of America
Operating temperature32°F to 104°F / 0°C to 40°C
Air supply systemLow pressure
Pump TypeCarbon rotary vane and oil-less motor
Pump VanesCarbon construction (4 vanes/ replaceable)
Pump Inlet filter50 Micron felt material with metal grid inlet filter housing
Pump Exhaust filter0.30 Micron HEPA
Pump Pressure gage2" / 5.08cm face, steel housing (0-15 psi) / (0-1.03 bar)
Pump Working press2-12 psi / 0.14-0.83 bar - 15 psi / 1.03 bar max
Pump Performance0-10 CFM / 0-16.99 m³/hr at 60 Hz - adjusted by pressure relief valve, 0-8 CFM / 0-13.59 m³/hr at 50Hz - adjusted by pressure relief valve
Pump Noise level90 dB, at 6 feet / 1.82 m: 74 dB, at 10 feet /3.04 m: 72dB
Motor (HP)3/4 HP
Motor in Volts115 V / 230 V AC, single phase
Motor (Hertz)60/50 Hz
Motor (RPM)1725 RPM at 60Hz / 1425 RPM at 50 Hz
Motor Current draw9.05 A for 115 V or on special request 4.6 A for 230 V
Length (in/cm)21 in / 53.34 cm
Width (in/cm)16 in / 40.6 cm
Height (in/cm)12 in / 30.4 cm
Weight (lb/kg)56 lb / 25.40 Kg
Sold byUnit
Return conditionsNo returnable if used. For more information about our return policy, please refer to the "Orders and Returns" link on the home page

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