Exhausters & Compressors

Figure 420 Jet Compressor with threaded pressure connection and flanged suction and discharge connections
Sectional drawing of Figure 425 Jet Compressor with manually-controlled spindles
Figure 426 Thermocompressor with actuator, stuffing box, spindle, nozzle, and diffuser
Figure 427 Jet Compressor with manually-controlled spindle and flanged connections

Thermocompressor / Jet Compressor

Principle of Operation

Jet Compressors are a type of ejector that use a jet of high-pressure gas as an operating medium to entrain a low-pressure gas, mix the two, and discharge at an intermediate pressure. Gases can be steam, air, propane, and others.

The Thermocompressor, also a type of Jet Compressor, is used when both motive and suction gases are steam. Thermocompressors have automatically-controlled spindles. They are used when pressure suction or discharge conditions vary and it is necessary to control discharge pressure or flow. Thermocompressor spindles are designed to act as temporary valves and provide tight shut-off. Thermocompressors are available in materials to fit operating conditions or as specified by the customer.

Fig. 420 Jet Compressors are flanged and have no regulating spindle. The pressure connection is threaded, the suction and discharge connections are flanged, and the nozzle is threaded into the body for easy removal and maintenance. The Fig. 425 Jet Compressor has all threaded connections and is equipped with a manually-controlled spindle which is used specifically when the unit operates at a steady load but where flexibility of the nozzle orifice is desired to compensate for changes in operating conditions. The Fig. 427 Jet Compressor is the flanged version of the Fig. 425.

Fig. 426 Thermocompressors have automatically-controlled spindles. The spindle can be operated with a diaphragm, piston, or motor actuator using any standard instrument signal, either electric or pneumatic. The Fig. 439 Thermocompressor is the threaded-connection version of the Fig. 426.


Fig. 420, Fig. 425 and Fig. 427 Jet Compressors have no moving parts. They can be manufactured from any machinable or castable material. Large units can be fabricated from any materials which are available in plate and are weldable. They can be installed in any position. Due to velocities involved, good mixing of dissimilar gases is obtained. Jet Compressors can replace mixing valves and at the same time boost pressure which replaces a compressor. Jet Compressors can reduce boiler steam demand or enhance the capacity of an existing boiler.

Fig. 426 and Fig. 439 Automatic Jet Compressors can be used in applications operating over a range of pressure and differential pressure. Automatic Jet Compressors may be utilized wherever available energy is being lost through reducing valves; such as high pressure steam reduced and desuperheated for process use and mixing of gases without use of mechanical compressors. Diaphragm and piston operators use any standard split or full range, electric, electronic, or pneumatic instrument signal. The control can be activated by temperature, pressure, flow, or suction to motive gas ratio.

Thermocompressor Refurbishment


Jet Compressor:


For more detailed information about Jet Compressors, Bulletin 4F and Bulletin 4F Supp. Literature.

To submit a Request for Quote (RFQ) for Jet Compressors, Adobe PDF or submit an online interactive RFQ Form for Gas Jet Compressor / Thermocompressor.

Schutte & Koerting, 2510 Metropolitan Dr., Trevose, PA 19053, USA
Tel: (215) 639-0900 Fax: (215) 639-1597 Email: