CN1314479C - injector - Google Patents

Abstract

An eductor (1) having an air gap (5), a venturi structure (3), and a non-return valve (19) located in the air gap (5). The non-return valve is removable and allows the eductor to be operated as an air gap eductor or a non-return valve eductor. A non-return valve cartridge (19) for installing in to the air gap (5) of an air gap eductor (1), so that the eductor can be operated as a non-return valve eductor. A method of retrofitting a non-return valve (19) in an air gap eductor (1).

Description

injector

Technical Field of the Invention

The field of the invention is that of injectors for mixing liquids, which use non-return valves. Also associated with modified air gap injectors.

Technical Background of the Invention

Ejectors are often used in industrial processes, for example, in hotels or in the food processing industry. Some cleaning chemicals are usually packaged and sold in the form of concentrated solutions, which need to be diluted to a suitable concentration according to a predetermined ratio when used. Scale-down concentrate dosers dilute the concentrate to the desired concentration and dispense the mixed diluted solution. Such instruments usually have a venturi device, commonly known as an eductor, which allows the concentrate to be drawn into a stream of water for dilution.

In an eductor the water flows through a channel, at the point where the channel widens the concentrated solution is thrown into the flow.

The injector is generally vertical in structure, and consists of a nozzle to form a direct downward jet of water. There is an air gap below the nozzle, and a Venturi tube structure below the air gap. During use the water jet enters the venturi structure through the air gap. The venturi structure consists of an inlet, a side channel for conveying the concentrated solution and a small reservoir for the concentrated solution to enter the water stream.

In order to make the solution diluted to a predetermined concentration, a flow measuring device needs to be installed in the equipment to detect the amount of concentrated solution in the incoming water flow. For example, flow measuring devices as described in US Patent No. 5,522,419 or WO 94/04857 are used in some injectors.

Typically, the injectors are supplied with water flow directly from the main water supply. In most water systems there is a brief vacuum in the flow of water. This condition causes the concentrate to flow back into the water stream. Obviously, this is undesirable and preventing backflow of the concentrated solution is also important to keep the water stream free from contamination by the concentrated solution.

There are two known devices for preventing contamination of the water supply from backflowing solution, the Air Gap (AA) Injector, which incorporates an air gap device between the nozzle and the Venturi device, which prevents backflow of the concentrate as previously described , because it is impossible for the water flow below to reach the water source through the air gap upwards. Any water flowing out of the inlet of the venturi unit will be diverted beyond the injector and will not flow back to the source. Air gap injectors can provide very effective protection against back flow. But this device has many disadvantages.

A mechanical check valve or line blocker (DB) is slightly less effective at preventing backflow than an air-gap injector, but it has far fewer disadvantages than an air-gap injector.

As is well known, an air gap device is a small device that combines an anti-backflow device and a solution mixing device. However, the air gap injector has several disadvantages. The water flow is exposed to the air when it passes through the air gap device. Dust or other particles in the working environment will affect the spraying effect of the water flow after entering the nozzle, which will increase the backflow caused by the splashing of the water flow and reduce the Venturi device working accuracy. Blockage of fluid flow prevents the injector from working effectively, and for this reason air gap injectors require regular maintenance.

Because the diluted solution is exposed to the air, air gap injectors cannot be used for dilution of solutions with liquids other than water as the diluent.

The other is the ejector that uses a one-way vacuum counterflow device. A one-way vacuum unit is a separate unit connected in series with an ejector. This device does not have the advantages of compact structure and anti-backflow device that the air gap injector has. In addition, the return flow effect of the injector with this structure is worse than that of the air gap injector.

Other backflow prevention devices, such as vacuum breaks.

Summary of the invention

The inventors have recognized that existing injectors are not capable of switching between air gap mode and check valve vacuum tube mode. Only select two-mode injectors enable such conversions. However, this is time-consuming and expensive. The limitations of known injector models make it impossible for a single injector to serve applications requiring both an air gap injector and a check valve vacuum tube injector.

One object of the present invention is to address the disadvantages of conventional injectors, especially to provide a system that can easily switch between the air gap mode and the one-way valve vacuum tube mode.

First of all, the present invention has a Venturi tube structure. When working in the air gap mode, the water flow will pass through the air gap to reach the Venturi tube. A detachable one-way valve is also installed in the air gap, so that the injector You can easily switch between the two modes.

Any suitable one-way device may be used for the movable check valve, for example, within the knowledge of those skilled in the art. It can be selected according to the degree of backflow prevention of the one-way device required. The check valve may have one or more outlets to discharge the returning solution out of the injector. The movable one-way valve is made of materials with resilience to chemical reagents, which are common in normal operation.

This mode allows the injector to be used as either an air gap injector or a check valve injector by placing the check valve in or out of the air gap. A check valve can also be used instead of a nozzle to spray liquid through the air gap.

It is beneficial to have injectors that can be converted between air gap and check valve types. For example: in a water dilution system, the size of the water flow and the dilution concentration requirements are often changed in various actual operations, so the requirements for the anti-backflow performance of the injector are also different. Compared with the previous invention, the present invention has obvious progress in that it can provide an air gap anti-backflow device or a one-way valve anti-backflow device suitable for different backflow prevention performance requirements.

The invention includes a movable one-way valve device which can be switched between two forms of air gap anti-backflow or one-way valve backflow prevention. Compared with the current injector, the biggest advantage is that when the anti-backflow requirement changes, the injector does not need to be replaced, as long as a special technology is applied to adapt to the work requirement. Provides a time-saving and cost-saving feature that allows the injector to switch between an air gap backflow preventer and a check valve backflow preventer.

Secondly, the present invention also introduces a non-return valve device which is movable and which can be installed at the air gap in the injector having the air gap and the inlet area of the venturi. The one-way valve assembly has an inlet for receiving water flow from a water source into the vacuum tube, an outlet for sending water flow into the inlet of the venturi, and a one-way valve between the inlet and the outlet.

Preferably, there is a sealing surface at the outlet for sealing the connection between the outlet of the vacuum tube device and the inlet of the venturi tube.

Preferably, there is also a sealing surface at the inlet of the one-way valve device to seal the connection between the inlet of the vacuum tube and the water source.

Preferably, the one-way valve has a core structure, and an elastic sleeve is placed outside the core structure. When the sleeve is in close contact with the core structure, it will prevent backflow between the sleeve and the core structure. This sealing effect is lost when expansion occurs due to fluid pressure at the inlet.

Preferably, the one-way valve device also has an outer cover, which can control the expansion degree of the elastic sleeve, and when liquid flows through, the sleeve and the outer cover will be tightly combined.

In this structure, when the inlet and outlet are closed, the water will flow back between the shrunk elastic sleeve and the outer cover. Preferably, the outer cover also has a device, which can discharge the backflow liquid out of the one-way valve when backflow occurs.

The check valve device used in the present invention can be installed or removed in the air gap device of the air gap injector. Provides an easy, economical way to retrofit existing air gap injectors. In this way, the present invention provides a convenient and economical device, which changes the practice of reinstalling different types of injectors or installing an accessory device to adapt to the backflow prevention.

Third, the existing invention also changes the structure of the air gap, using a dual structure of a venturi tube and an air gap, including installing a one-way valve in the air gap.

Adding the one-way valve to the air gap of the injector optimizes the structure of the injector and avoids many disadvantages of the air gap injector, such as: regular maintenance, no need to reinstall a new injector or other parts of the liquid delivery equipment A check valve is installed to switch between the two.

Another effect of the present invention is that on the basis of existing equipment, the conversion between the two injectors can be realized without mastering special techniques. Save time and money when replacing other types of injectors and installing additional check valve devices.

The method of preventing backflow with a mechanical barrier is more suitable for injectors used to dilute toxic or harmful liquids.

Brief Description of the Diagram of the Invention

The accompanying drawings of the present invention are described as follows:

Figure 1 is an exploded view of the injector of the present invention, including a one-way valve structure, as described in the second aspect of the present invention.

Figure 2 shows a front view of the exploded structure of the injector and check valve in Figure 1.

FIG. 3 shows an assembled front view of the injector of FIGS. 1 and 2 .

Specific embodiments of the invention

Figures 1-3 show an injector according to an embodiment of the present invention, arranged vertically, comprising an inlet section 2, a venturi structure 3, and a main body structure 4 which is a horizontally structured cylinder forming a 2 and the air gap 5 between the venturi structure 3. The venturi structure 3 consists of an inlet 6 , a side channel 7 for conveying concentrated solution into the venturi structure 3 , and an outlet 8 . The Venturi structure also includes a Venturi body (not shown) for mixing the water and concentrated solution, and side channels for swirling the liquid flow around the Venturi body structure. Venturi structures 3 are well known and therefore will not be described in detail here.

FIG. 1 also partially shows a water supply pipe 10 comprising a vacuum pipe 11 of a conventional manual switch and a connection pipe 12 which can be locked into the inlet part 2 by a bayonet connection.

Described below is the general form of the inlet section 2 comprising an inlet that seals on the connecting tube 12 and is capable of spraying water through the air gap to the venturi structure 3 in the air gap mode of operation in which the non-return valve 19 is not installed. 6 nozzles (not shown in the figure).

Shown in Figure 1 is an exploded view of a movable one-way valve 19 which, in use, is located in the air gap 5 of the main structure 4 (shown in Figure 3).

The one-way valve 19 comprises a core structure 20, an elastic sleeve 25 which is inflatable and acts as a vacuum membrane, and a protective outer cover 26. There is an inlet pipe 21 on the upper part of the core structure 20, which can lead the water in the water supply pipe 10 into the vacuum pipe, a pipe 22 extending from the bottom of the inlet pipe 21 and an outlet in the rib structure 24 connecting the inlet pipe 21 pipe and the extension pipe 22 twenty three.

The expandable elastic sleeve 25 made of rubber material, such as silicone resin, can cover the outside of the extension tube 22 and the outlet 23 after being installed with the vacuum tube structure. When the vacuum tube is installed and there is no pressurized water flow through the inlet pipe 21, the elastic sleeve 25 will tightly surround the extension tube outside, and the liquid will not pass between the extension tube 22 and the elastic sleeve 25.

The housing 26 comprises a main body structure 27 made of hard plastic with helical rib-like reinforcements 27a, enabling the liquid to flow through the housing into the outlet 28 of the air gap 5 after the vacuum tube is installed and secured in the air gap 5 And the outlet pipe 29 connected to the inlet 6 of the venturi device. When the vacuum tube is installed, the elastic sleeve 25 and the core structure 20 will be covered by the outer cover.

The inlet pipe 21 of the one-way valve 19 has two O-rings 21a, which can play a sealing role after the connecting pipe 12 is inserted. The outlet pipe 29 also has an O-ring 29a which can be used to seal the connection with the inlet 6 of the venturi structure 3 . After the water supply pipe 10 is removed from the inlet 2, the one-way valve device can be installed in the injector, so that the injector is converted from the air gap working mode to the one-way valve working mode. The water nozzle is removed from the inlet, the one-way valve 19 is inserted, the outlet pipe 29 enters the inlet 6 through the inlet, and the water supply pipe 10 is connected to the inlet 21 again. After installation, the upper end of the outer cover 26 tightly surrounds the edge 25a of the elastic sleeve 25, and the edge 25a of the elastic sleeve 25 is also in contact with the lower end of the inlet pipe 21 here, and is sealed here.

During use, water flows from the water supply pipe 10 into the inlet pipe 21 and flows out from the outlet 23 . The pressure of the water flow causes the elastic sleeve 25 to expand and separate from the extension tube 22 . The expansion provides a path for fluid flow between the expanded elastic sleeve 25 and the extension tube 22 . The elastic sleeve 25 can expand to the outer cover 26 of the main structure 27 at most, and the outer cover limits the expansion range of the elastic sleeve, so that the elastic sleeve 25 can form a sealed water flow channel from the inlet to the outlet of the vacuum tube.

Water flows from the inlet pipe 21 to the outlet pipe 29 of the housing as a result of the expansion of the elastic sleeve. A jet of water is formed at the outlet pipe 29, and the water directly flows into the inlet 6 of the venturi to flush and dilute the concentrate in the side chamber. Finally the water and the newly formed dilute solution exit the injector through the outlet 8.

When the water flow stops, the elastic sleeve 25 is retracted to the extension pipe 22, and is tightly attached to the periphery of the extension pipe. In this way, the solution can be prevented from flowing back into the water supply pipe 10 by the one-way valve 19 .

If there is no water flow into the one-way valve 19 from the water supply pipe 10, for example: the water pressure in the main water supply pipe suddenly drops, and the backflow occurs inside the Venturi structure 3, the liquid flow will enter the one-way valve along the venturi inlet 6. Outlet pipe 29 of the valve. Although, it has been mentioned above that the liquid flow cannot enter the water supply pipe because the elastic sleeve 25 is tightly attached to the periphery of the extension pipe 22 . But the liquid flow will enter the gap between the main structure 27 and the elastic sleeve 25 , and then flow out through the outlet 28 of the one-way valve 19 .

FIG. 3 shows the assembled injector with the one-way vacuum tube installed inside the main structure 4 of the air gap 5 . The outlet 28 of the body structure 27 of the non-return valve 19 can be seen through the open end of the body structure 4 . The solution exits the one-way valve 19 through the outlet 28. For example, in the case of backflow solution in the venturi structure, the solution can flow into the air gap through the outlet 28 and exit the injector through the open end of the main structure 4 of the injector.

Claims (6)

1. injector, comprise venturi tube structure (3), the air gap (5), under the mode of operation of the air gap, current can pass the check valve that can remove that the air gap enters venturi tube structure (3) and is arranged in the air gap (5), and injector just can be implemented in the conversion between the air gap operator scheme and the check valve operator scheme like this.

2. according to the injector of claim 1, wherein in the air gap operator scheme, injector has a nozzle, is used to provide described liquid jet, and nozzle can be removed and be replaced by check valve when conversion.

3. according to the injector of claim 2, wherein check valve has an outlet (29), current can be imported in the venturi tube structure in use.

4. according to any one the injector in the claim 1 to 3, check valve wherein makes current pass the air gap and arrives venturi tube structure for current provide the first fluid passage of the sealing of passing the air gap when opening; And second fluid passage is provided, after the first passage of described sealing is closed,, can make withdrawing fluid discharge check valve for providing another path by the liquid that is back in the venturi tube structure in the air gap.

5. a transformation has the method for the injector of venturi tube structure (3) and the air gap (5), is included in the described the air gap check valve is installed.

6. according to the method for claim 5, wherein the air gap injector also comprises nozzle, and described nozzle is used to guide current, and described method also comprises the step of removing nozzle from injector.

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