Vacuum unit and a vacuum toilet system comprising such a unit

• US 6,513,174 B1
• Filed: 01/16/2002
• Issued: 02/04/2003
• Est. Priority Date: 05/17/1999
• Status: Expired due to Term

• Current Assignee: Avac Vakuumteknik AB
• Original Assignee: Avac Vakuumteknik AB
• Inventors: Johansson, Håkan
• Primary Examiner(s): Fetsuga, Robert M.
• Application Number:
  US09/959,784
• Time in Patent Office: 384 Days
• Field of Search: 432/1, 432/3, 443/1, 443/4, 417/160
• US Class Current: 4/431
• CPC Class Codes: E03F 1/006 Pneumatic sewage disposal systems; accessories specially adapted therefore

Abstract

A vacuum unit, particularly for a vacuum toilet system, includes first and second valves (4, 6), an ejector (10) connected to the first valve, and a piston valve (16) which is connected between the ejector and the second valve. The unit is characterised in that an overpressure and a vacuum can both be generated from the first valve (4) by controlling the state of the piston valve by the combination of the states of the first and the second valves. A vacuum toilet system is also described.

Claims

1. A vacuum unit that comprises

a first valve (4) that can be connected to a compressed-air source (32) and that has a first, closed position and a second, open position;

a second valve (6) that can be connected to a compressed-air source (32);

an ejector (10) that includes an inlet nozzle (10a), an outlet nozzle (10b), and a vacuum opening (10c), wherein the ejector is connected to the first valve (4) via the inlet nozzle, and to a first connection (U1) of said vacuum (2) via said vacuum opening; and

a piston valve (16) that has a first inlet (16a), a second inlet (16b) and an outlet (16c), wherein said piston valve has an open position in which the outlet (16c) connects with the first inlet (16a), and a closed position in which the outlet (16c) is not connected to the first inlet (16a) or the second inlet (16b), and with which piston valve (16) the first inlet is connected to the outlet nozzle (10b) of the ejector, the second inlet is connected to the second valve (6), and the outlet is connected to a second connection (U2) of said vacuum unit, said vacuum unit being characterised in that the second valve (6) has a first position in which the second inlet (16b) of the piston valve (16) connects with the surroundings, and a second position in which

the second inlet (16b) of the piston valve (16) connects with the compressed-air source;

wherein the piston valve (16) is adjusted to an open position with the second valve (16) in its first position, whereby an open position of the first valve (4) causes a sub-pressure to be generated in the vacuum opening; and

wherein

the piston valve (16) is adjusted to a closed position with the second valve (6) in its second position, whereby opening of the first valve (4) causes an overpressure to be generated in the vacuum opening.

2. A vacuum unit according to claim 1, characterised in that at least one of said first and second valves (4, 6) is a solenoid valve.

3. A vacuum unit according to claim 1, characterised in that the second valve (6) is a 3/2-valve.

4. A vacuum unit according to claim 1, characterised in that the valves can be connected to mutually the same compressed-air source through the medium of a common inlet.

5. A vacuum unit according to claim 1, characterised by a pressure sensor connected to the first vacuum unit connection (U1).

6. A vacuum unit according to claim 1, characterised by a safety valve connected to the first connection (U1) of said vacuum unit (2).

7. A vacuum unit according to claim 1, characterised in that said unit has been manufactured by an injection moulding process.

8. A vacuum unit according to claim 7, characterised in that said unit is made of acetal resin.

9. A vacuum toilet system that includes a toilet (20), a water container (28) connected to said toilet, an intermediate storage tank (30) connected to said toilet via an inlet valve (22), a storage tank (26) connected to the intermediate storage tank via an outlet valve (24), and a compressed-air source (32), characterised by a vacuum unit (2) according to claim 1 connected to the compressed-air source via said first and second valves (4, 6), and connected to said intermediate storage tank via said first connection (U1) and to said storage tank via said second connection (U2).