Air pressure driven vacuum sewer system

• US 5,813,061 A
• Filed: 07/05/1996
• Issued: 09/29/1998
• Est. Priority Date: 12/20/1993
• Status: Expired due to Term

• Current Assignee: MAG Aerospace Industries Incorporated
• Original Assignee: EVAC AB
• Inventors: Tornqist, Hans
• Primary Examiner(s): Fetsuga, Robert M.
• Application Number:
  US08/674,580
• Time in Patent Office: 816 Days
• Field of Search: 4/321, 4/431, 4/434, 417/151, 417/188, 417/189, 417/191, 137/844, 137/853, 137/895, 406/11, 406/105, 406/144, 406/153, 239/533.13, 239/602
• US Class Current: 4/431
• CPC Class Codes: E03F 1/006 Pneumatic sewage disposal systems; accessories specially adapted therefore
• CPC Class Codes: Y10T 137/7889 Sleeve

Abstract

A vacuum sewer system comprises a normally closed sewer valve connected between the outlet opening of a waste receiving unit to be emptied and a sewer pipe, and an ejector. The ejector is an integrated part of the sewer pipe. The sewer pipe includes one portion forming a suction pipe of the ejector and another portion forming a discharge pipe of the ejector.

Claims

1. A vacuum sewer system comprising at least one waste receiving unit to be emptied, said unit having an outlet opening, a sewer pipe having an upstream end and a downstream end, a normally closed sewer valve at the outlet opening of the waste receiving unit and connected between the outlet opening of the waste receiving unit and the upstream end of the sewer pipe, a sewage collecting container connected to the sewer pipe at the downstream end thereof for collecting sewage from the sewer pipe, an ejector having a suction pipe in communication with the sewer pipe, a discharge pipe, and a working medium supply inlet, whereby a considerable partial vacuum is created in the suction pipe when the sewer valve is in closed position and a pressurized working medium is supplied to the ejector by way of the working medium supply inlet so that sewage in the waste receiving unit is forced into the sewer pipe when the sewer valve is opened,

wherein the ejector is a gas-driven ejector and is integrated into the sewer pipe so that the suction pipe and the discharge pipe of the ejector form respective parts of the sewer pipe, thereby dividing the sewer pipe into an upstream portion, in which sewage is transported due to pressure difference between the ambient atmosphere and partial vacuum created by the ejector, and a downstream portion, in which sewage transport is at least assisted by pneumatic pressure created by the ejector in its discharge pipe, and

wherein between the waste receiving unit and the ejector there is at least one security device arranged to rapidly dissipate pressure if the pressure between the ejector and the waste receiving unit exceeds the pressure in the waste receiving unit when the sewer valve is open, the security device being a relief valve in the form of a flexible hose which is normally in a bent position in which a closing fold is formed in the hose.

2. A vacuum sewer system comprising at least one waste receiving unit to be emptied, said unit having an outlet opening, a sewer pipe having an upstream end and a downstream end, a normally closed sewer valve at the outlet opening of the waste receiving unit and connected between the outlet opening of the waste receiving unit and the upstream end of the sewer pipe, a sewage collecting container connected to the sewer pipe at the downstream end thereof for collecting sewage from the sewer pipe, an ejector having a suction pipe in communication with the sewer pipe, a discharge pipe, and a working medium supply inlet, whereby a considerable partial vacuum is created in the suction pipe when the sewer valve is in closed position and a pressurized working medium is supplied to the ejector by way of the working medium supply inlet so that sewage in the waste receiving unit is forced into the sewer pipe when the sewer valve is opened,

wherein the ejector is a gas-driven ejector and is integrated into the sewer pipe so that the suction pipe and the discharge pipe of the ejector form respective parts of the sewer pipe, thereby dividing the sewer pipe into an upstream portion, in which sewage is transported due to pressure difference between the ambient atmosphere and partial vacuum created by the ejector, and a downstream portion, in which sewage transport is at least assisted by pneumatic pressure created by the ejector in its discharge pipe, and

wherein the discharge pipe of the ejector comprises a flexible sleeve located within a zone where the function of the ejector causes said considerable partial vacuum, and the system comprises a pipe that surrounds the flexible sleeve, whereby a space is formed between the external surface of the flexible sleeve and the wall of the surrounding pipe, which space is sealed from the interior of the sewer pipe and is in communication with the ambient atmosphere, so that when the ejector operates, the sleeve contracts under the influence of flow forces and the ambient atmospheric pressure to a diameter that is considerably smaller than the diameter of the sewer pipe.

3. A system according to claim 2, wherein the sleeve has a length of about 10 cm when in the mounted position.

4. A system according to claim 2, wherein the sleeve is provided with stiffener means for guiding contraction of the sleeve.

5. A passenger transport vehicle comprising a vehicle body, a compressed air system for generating compressed air and distributing the compressed air to operating devices of the vehicle, and a vacuum sewer system, wherein the vacuum sewer system comprises at least one waste receiving unit, said unit having an outlet opening, a sewer pipe having an upstream end and a downstream end, a normally closed sewer valve at the outlet opening of the waste receiving unit and connected between the outlet opening of the waste receiving unit and the upstream end of the sewer pipe, a sewage collecting container connected to the sewer pipe at the downstream end thereof for collecting sewage from the sewer pipe, and an air-driven ejector having a suction pipe in communication with the sewer pipe, a discharge pipe, a compressed air supply inlet, and a compressed air valve connected between the compressed air system and the compressed air inlet, whereby a considerable partial vacuum is created in the suction pipe when the sewer valve is in closed position and the compressed air valve is opened, whereby sewage in the waste receiving unit is forced into the sewer pipe when the sewer valve is opened, and wherein the ejector is integrated into the sewer pipe so that the suction pipe and the discharge pipe of the ejector form respective parts of the sewer pipe, thereby dividing the sewer pipe into an upstream portion, in which sewage is transported due to pressure difference between the ambient atmosphere and partial vacuum created by the ejector, and a downstream portion, in which sewage transport is at least assisted by pneumatic pressure created by the ejector in its discharge pipe, and wherein the discharge pipe of the ejector comprises a flexible sleeve located within a zone where the function of the ejector causes a considerable vacuum, and the vacuum sewer system comprises a pipe that surrounds the flexible sleeve, whereby a space is formed between the external surface of the flexible sleeve and the wall of the surrounding pipe, which space is sealed from the interior of the sewer pipe and is in communication with the ambient atmosphere, so that when the ejector operates, the sleeve contracts under the influence of flow forces and the ambient atmospheric pressure to a diameter that is considerably smaller than the diameter of the sewer pipe.

6. A vehicle according to claim 5, wherein the sleeve has an axial length of about 10 cm when in the mounted position.

7. A vehicle according to claim 5, wherein the sleeve is provided with stiffener means for guiding contraction of the sleeve.