NO20180783A1

NO20180783A1 - Non-return arrangement or backflow prevention device for vacuum sewage system

Info

Publication number: NO20180783A1
Application number: NO20180783A
Authority: NO
Inventors: Jan Helge Skomsøy
Original assignee: Jets As
Priority date: 2018-06-06
Filing date: 2018-06-06
Publication date: 2019-12-09

Description

The present invention relates to a non-return arrangement or backflow prevention device for vacuum sewage system, the system including one or more vacuum generator/s, in particular liquid ring screw pump/s with integrated macerator, and further including beyond the vacuum generator/s one or more tubular collectors or suction pipelines connected to the vacuum generator/s and one or more toilets, urinals, grey water sinks etc. connected to the suction pipeline/s.

Vacuum sewage systems of the above-mentioned kind are commonly known and dominating in connection with the use onboard ships, aero planes and trains. However, on land such systems are also increasingly used and the background for such increased use is primarily the reduced use of water and easy handling and treatment of waste water, as well as the flexible system as regards installation of the pipes given by such system.

The applicant of the present application introduced in 1987, cf. EP patent No. 0287 350, a novel vacuum sewage system where the vacuum in the system is generated by means of a liquid ring screw pump and where the pump is used as well to discharge the sewage from a vacuum tank or the like to which it is connected.

EP patent No. 0 454 794, also filed by the applicant, further shows a revolutionary improvement of a vacuum sewage system where the liquid ring pump is provided with a grinder or macerator and is connected directly with the suction pipe of the system, whereby vacuum is generated in the sewage suction pipe and sewage is discharged directly from the system by means of the pump.

There are two types of vacuum sewage systems; a) systems running continuously, socalled CVS systems (Continuous Vacuum systems) and systems where the vacuum is created when needed before flushing of a toilet or urinal, so-called VOD systems (Vacuum On Demand). The present invention is applicable for both CVS and VOD vacuum sewage systems. Such vacuum systems are provided with sensors in particular for the detection and measuring of vacuum, but for some applications also for measuring temperature. Such sensors are usually provided in spaces of the vacuum system such as piping or in conjunction with vacuum pumps or tanks where there is a build up of vacuum in the space surrounding the sensor. Sewage consists of waste material such as feces and paper and when flushing a toilet by the opening of the discharge valve of the toilet, air is initially entering the toilet from the surrounding atmosphere and the pressure in the system increases. Then, as the slug of sewage from the flushed toilet passes downwards from the toilet and into the piping, the slug passes the small volume surrounding the probe and the local vacuum sucks sewage towards the probe surface and builds up on the probe measuring head. This has proved to be a problem for such systems used over time. The same problem is also seen in vacuum operated valves, such as discharge valves for such systems as the sewage is drawn into the membrane chamber or activation cylinder for such valve.

It is formerly known from WO/ 99/32816 a valve means installed in a junction or branch of a main flow pipe in a vacuum system where a separately valve body in the form of a mechanical flap is arranged to direct the flow in one branch direction while closing the other main direction and vice versa. This solution is developed for use in situations where there intermittently is a flow through the branch pipe form a toilet etc. and where the branch pipe is closed by the valve body when there is flow in the main pipe to avoid backflow to the branch pipe. This solution cannot be used for the purpose of the present invention.

EP 1255 065 B1 shows a back-flow valve device including a flow pipe with a branch pipe where a flexible, cylindrical body section is provided on the inside of the flow pipe and where the flexible body section covers the opening of the branch pipe such that back flow to the opening of the branch pipe is prevented. Long time testing of this known solution has proved that there is a leakage from the flow pipe to the branch pipe when used in vacuum sewage systems due to changing pressure conditions and the build-up of sewage in branch pipe, and thereby a probe suction opening, over time is not fully avoided.

With the present invention is provided a solution which eliminates or vastly reduces the abovementioned disadvantages and problems related to backflow and thereby reduces maintenance of the vacuum system.

The invention is characterized by the features as defined in the attached independent claim 1.

Advantageous embodiments of the invention are further defined in the attached dependent claims 2 -5.

The invention will be further described in the following by way of examples and with reference to the drawings where:

Fig. 1 shows, as an example, a perspective view of a sewage non-return arrangement according to the invention, and

Fig. 2 shows the non-return sewage arrangement as shown in Fig. 1, in longitudinal cross section.

Fig. 3 shows an expanded view of the device shown in the foregoing Figs.1 and 2.

Fig. 1 shows, as stated above, a perspective view of a vacuum sewage non-return or backflow prevention arrangement or device 1 according to the invention. It includes, as shown in Fig.1, a flow pipe section 2 and a branch section 3. Preferably the “housing” of the device with the flow pipe section and branch section may be a standard type 45<0>branch pipe connection.

Further referring to Figs.2 and 3, the flow-pipe 2 is provided with a flexible hose like member 4 fitting smoothly within the inner space of the flow pipe section 2. The hose like member 4, preferably made of a suitable rubber material, is at its inner end provided with an expanded ring section 18 which is adopted to rest against an inclining part 19 of the end section 20 (connection part) of the flow pipe 2. On the other hand, an outwardly protruding hock member 17 on the hose like member 4 is, when put in place within the pipe section 2, provided to hock onto the intersection between the flow pipe 2 and branch section 3 as shown in Fig.2 and is thus held in place within the pipe section.

The purpose of the flexible member is to prevent backflow into the branch section 3. However, as stated above, long time use and testing in vacuum systems have proved that the flexible hose like member does not fully (to 100%) prevent backflow to the branch section, and over time this may cause build-up of material or moisture problem for pressure probe(s) or pneumatic devices driven by the vacuum in the flow pipe 2. To ensure non-return to or through the branch pipe section 3, an additional closing device 7 is provided in the branch pipe 3. This device 7 is in the preferred embodiment shown in the figures in the form of a rubber element comprising a ring-formed gasket part 14 and hollow finger-formed part 15. The finger-formed part 15 is provided with a slit (long narrow cut) at its outer end, whereby the flexibility of the rubber keeps the ends of the slit pressed together (closed) when the pressure in the flow pipe (2) increases such as when flushing of a toilet takes place. The rubber closing device 7 is held in place within the branch section 3 by means of a cylindrically shaped gasket holder 6 being provided with an inwardly, circumferentially protruding projection 22 fitting into a complimentary provided recession in the ring-formed gasket part 14. The gasket holder on the other hand is held in place in the branch section 3 by an end cover 5. Thus, the gasket holder 6 fits neatly within the end cover which is cylindrically formed and with an end plate being provided with one or more probes or with a nipple or other connecting means 10. The gasket holder 6 is locked to the end cover 5 by means of a locking knobs 12 fitting into complementary holes 11 (one on each side) in the cylindrical wall on the end cover 5. Vertical slits 13 on each side of the knobs of the holder 6 enables the knobs 12 to flex inwardly when withdrawing or inserting the holder 6 in the end cover 5. Since the housing of the device according to the invention may be a standard 45<0>branch pipe connection, the connecting ends of the branch pipe are each provided with gaskets 8, 9. Thus, the device according to the invention may, with its standard dimensions, be used for standard PP or PVC drainage piping.

Claims

1. Non-return or backflow prevention arrangement or device (1) for vacuum sewage systems, including a flow pipe section (2) and a branch pipe section (3), where the flow section (2) is provided with a flexible hose like member (4) fitting within and held in place within the inner space of the flow pipe section (2), the hose like member (4) being made of a suitable material such as rubber,

c h a r a c t e r i s e d i n t h a t

to prevent back-flow to or through the branch pipe section (3), an additional non-return or closing device (7) is provided in the branch pipe section (3) beyond the flexible hose member (4).

2. Non-return or backflow prevention arrangement or device according to claim 1,

c h a r a c t e r i s e d i n t h a t

the non-return device (7) is in the form of a rubber element comprising a ring-formed gasket part (14) to be fixedly held within the branch section (3) and hollow finger-formed part (15) where the finger-formed part (15) is provided with a slit at its outer end, whereby the flexibility of the rubber keeps the ends of the slit pressed together thereby preventing backflow when the pressure in the flow pipe (2) increases.

3. Non-return or backflow prevention arrangement or device according to claims 1 and 2, c h a r a c t e r i s e d i n t h a t

the closing device (7) is held in place within the branch section (3) by a cylindrically shaped gasket holder (6) being provided with an inwardly, circumferentially protruding projection (22) fitting into a complimentary provided recession in the ring-formed gasket part (14).

4. Non-return or backflow prevention arrangement or device according to claims 1, 2 and 3, c h a r a c t e r i s e d i n t h a t

the gasket holder (6) is held in place in the branch section (3) by means of an end cover (5), whereby the gasket holder (6) fits neatly within the end cover which is cylindrically formed and with an end plate being provided with one or more probes or a nipple or other connecting means (10).

5. Non-return or backflow prevention arrangement or device according to claims 1- 4,

c h a r a c t e r i s e d i n t h a t

the non-return device (1) housing is a standard 45<0>branch pipe connection.