JPH1176780A - Fine foam supply device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To efficiently produce fine foams with a simple structure and to supply good fine foams efficiently. SOLUTION: A suction device 15 for forming bubbles in a liquid 10.
An inlet horizontal portion 22 which is connected and comprises a substantially horizontal flow path;
A fine foam separation unit having an upright portion 24 of a flow passage formed substantially vertically downstream of the inlet horizontal portion 22 and an outlet horizontal portion 26 provided downstream of the upright portion 24 and having a substantially horizontal portion. 20 are provided. The liquid containing fine bubbles is passed through the fine foam separation section 20 to separate and supply the fine foam 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine foam supply apparatus which forms fine bubbles in various liquids, and separates and supplies fine bubbles obtained therefrom.

[0002]

2. Description of the Related Art Conventionally, in the production of fine foams, a method of producing fine foams by blowing gas into a liquid from a diffuser plate having many fine holes, and a method of producing a chemical change in a liquid by causing a chemical change in the liquid. There is a method of mixing a chemical substance which generates air bubbles into a liquid to generate fine foam.

Further, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 7264, a gas pressurized by a gas-liquid mixing device is introduced into a liquid flow path to form a gas-liquid mixed flow, and the gas-liquid mixed flow is injected into a liquid to be foamed. In addition, a device that forms a foam by fine bubbles has been proposed.

[0004]

In the case of using the former diffuser plate of the above-mentioned prior art, the holes of the diffuser plate are extremely small with a few μm, and the holes are easily clogged, and maintenance and management are difficult. Requires a lot of man-hours and cost. In addition, since the formed bubble diameter is relatively large, the fluidity of the foam is poor, and it has been difficult to supply the foam by piping. In addition, when chemical change is used, the gas forming bubbles is limited to the gas generated by the chemical change, so that the range of use is limited. There was also a problem that it would be mixed in.

In the latter case of the above-mentioned prior art, in order to separate the fine bubbles from the liquid, it is necessary to separate and collect the fine bubbles which float on the liquid surface and float on the liquid surface. However, fine bubbles cannot be efficiently recovered from the liquid. Further, it takes time for the fine bubbles to float in the liquid, and the recovery rate of the fine bubbles in the liquid is not good. Furthermore, since it takes time to float the microbubbles, there is also a problem that the microbubbles are combined with each other in the liquid to become large bubbles and the state of the foam deteriorates.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is capable of efficiently producing fine foams with a simple structure, and supplying fine foams efficiently. The purpose is to provide.

[0007]

According to the present invention, there is provided a fine bubble forming apparatus for forming fine bubbles in a liquid, and an inlet horizontal portion to which the fine bubble forming apparatus is connected and comprising a substantially horizontal flow path; A fine foam separation portion comprising an upright portion of a flow passage formed substantially vertically downstream of the inlet horizontal portion, and an outlet horizontal portion provided downstream of the upright portion and having a substantially horizontal portion; This is a fine foam supply device in which a liquid containing fine bubbles sent from a bubble forming device passes through the fine foam separation section and is separated into the fine foam and the liquid to obtain the fine foam.

Further, in the microbubble forming apparatus for forming microbubbles according to the present invention, a throttle section such as a venturi tube or an orifice provided in a liquid flow path and a flow path following the throttle section are gradually widened. An expanding portion, a gas inflow portion formed at a slightly downstream side of the throttle portion and having a constant cross section, and a suction device including a gas inlet provided in the gas inflow portion, and a suction device provided downstream of the expanding portion. A pressurizing / mixing unit that pressurizes and mixes the liquid in the flow path and the gas that has flowed in from the gas inlet; and the fine / foam separating unit that is provided on the outlet side of the pressurizing / mixing unit. And a jetting unit such as a nozzle for jetting the jet to a nozzle.

[0009] The microbubble forming apparatus for forming microbubbles may include a branch point where the flow paths are branched into a plurality of paths in the middle of the flow path of the liquid, and at least one of the plurality of flow paths branched in parallel. A venturi tube or an orifice provided at one end, an inflow portion located downstream of the throttling portion and having at least an inflow port through which gas flows, and a flow passage provided downstream of the inflow portion. And a confluent part which is provided at the downstream side of the widened part or the merging point for re-merging the plurality of parallel flow paths. And a pressurized mixing section for pressurizing and mixing a gas-liquid mixed flow of the liquid and the gas flowing from the inlet, and the gas-liquid mixed flow provided at the outlet side of the pressurized mixing section to the fine foam separation section. Equipped with an injection unit such as a nozzle Those were.

Further, at least one of the inflow ports is for gas to flow in, and the other inflow port is for flowing in a surfactant mixed with the liquid. The inflow section is provided downstream of the flow path following the throttle section and has a slightly larger cross-sectional area than the throttle section and an equal cross-sectional area in the flow path direction. Further, a surfactant is supplied into the liquid by a chemical injection pump in the middle of the liquid flow path.

In the fine foam supply apparatus according to the present invention, the gas sent from the outside is mixed with the liquid sent to the suction device to form fine bubbles, and the gas-liquid mixed flow having the fine bubbles stands upright in the fine foam separation section. The fine bubbles are effectively separated upward by utilizing the floating movement of the fine bubbles and the bent channel shape while passing through the horizontal part of the outlet from the part, so that the fine bubbles can be separated and supplied.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fine foam supply apparatus according to the present invention will be described below with reference to the drawings. Figure 1
FIG. 3 shows a first embodiment of the fine foam production apparatus of the present invention.
As shown in FIG. 2, there is provided a pipe 12 for supplying a liquid 10 which is foamed to form fine bubbles, and a pump 14 for sending the liquid is provided in the middle of the pipe 12. A suction device 15 for forming microbubbles in the liquid 10 is connected to a pipe 12 on the downstream side of the pump 14, and an injection unit for injecting the liquid 10 is further provided at a distal end of a pipe 17 downstream thereof. A nozzle 18 having a certain through hole 16 is connected.

The nozzle 18 is connected to an inlet horizontal part 22 of a Z-shaped fine foam separation part 20 for separating fine bubbles in the liquid. The fine foam separation section 20 includes an inlet horizontal section 22 formed of a substantially horizontal flow path, and an upright section 24 of a flow path formed to stand substantially vertically in the downstream of the inlet horizontal section 22.
And an outlet horizontal portion 26 provided downstream of the upright portion 24 and having a substantially horizontal portion. As shown in FIG. 1, a separation plate 27 for facilitating the separation and recovery of the separated fine foam 28 and the liquid 10 is provided at the boundary between the liquid 10 and the fine foam 28 in the outlet horizontal portion 26. Further, as shown in FIG. 2, a liquid pipe 29 a for passing excess liquid is provided below the outlet horizontal section 26, and a foam pipe 29 b for separating and supplying the fine foam 28 is connected above the outlet horizontal section 26. 10 and the fine foam 28 may be separately introduced.

Further, the suction device 15 provided at the downstream end of the pipe 12 is integrally formed as shown in FIG.
In the middle of the flow path 30 through which the liquid flows, the flow path 30 has a branch point 31 where the flow path 30 branches in parallel, and the flow paths 30 branched in parallel are provided with throat parts 32 and 33 as throttle parts, respectively. , Following the throats 32 and 33, on the downstream side,
An inflow portion 34 into which a gas such as air flows and an inflow portion 35 into which a surfactant flows are formed. Each of the inflow portions 34 and 35 is formed in a cylindrical shape slightly larger in diameter than each of the throat portions 32 and 33, and has the same cross-sectional area in the flow path direction. A gas inlet 36 into which gas flows in from the outside is formed in the inflow portion 34, and an inlet 37 through which the surfactant flows in from the outside is opened in the inflow portion 35.
As shown in FIG. 2, a gas pipe 38 is connected to the gas inlet 36, and a gas flow control valve 39 is provided in the gas pipe 38. A pipe 40 through which the surfactant flows is connected to the surfactant inlet 37.

Downstream of each of the inflow sections 34 and 35, there is formed a widening section 42, 43 in which the flow path is gradually widened. Downstream of the widening section 42, 43, a plurality of parallelly branched flow paths are provided. A merge point 44 is formed to merge again. Downstream of the junction 44, the liquid 10 in the flow path and the inlet 3
A pipe 17 is provided as a pressurizing and mixing section for pressurizing and mixing the gas and the surfactant flowing from 6, 37, and a nozzle section 18 as an injection section is provided at the outlet side of the pipe 17 of the pressurizing and mixing section. ing.

Next, the operation of the fine foam supply apparatus of this embodiment will be described below. Liquid to be foamed 10
In the liquid 10, which has been pressure-fed by the pump 14 and has flowed into the suction device 15, the flow branches at the branch point 31 of the flow path 30, reaches the maximum flow velocity at the throats 32 and 33 of each flow path, and the static pressure becomes minimum. , Downstream inflow portions 34, 35, spread portion 4
Via 2 and 43 the static pressure increases again. Expanding part 42, 4
After 3, the branched channels merge again at the junction 44. Here, the liquid 10 flows through the Venturi tubular flow path, so that the static pressure is relatively low at the throat parts 32 and 3.
Gas flows into the flow of liquid 10 from an inlet 36 which opens at an inlet 34 slightly downstream of 3. Inflow section 34
Is only slightly wider than the throat 32, so that the static pressure in this part is also relatively almost the lowest, and the throat 32
Since the flow path is slightly wider, gas is easily sucked into the flow path. Similarly, in the inflow section 35, the surfactant is sucked into the liquid 10 in the flow path from the inflow port 37.

The gas that has flowed into the liquid flow from the inlet 36 becomes bubbles and the liquid 10 in the flow path together with the suction device 15.
The fluid flows to the outlet portion through the expanding portion 42 of the gas, and the flows merge at the junction point 44 to form a gas-liquid mixed flow together with the liquid containing the surfactant and flow into the pipe 17 which also serves as the pressurized mixing portion. Piping 1
In 7, the flow velocity decreases and the static pressure of the flow relatively increases, so that the gas that has become bubbles dissolves in the liquid. The pipe 17 is preferably set to a Reynolds number or more at which the flow becomes turbulent so that the liquid containing fine bubbles and the liquid containing a surfactant are uniformly mixed. For example, when the pipe 17 has a circular cross section, the critical Reynolds number at which turbulent flow occurs is about 2300
Therefore, the Reynolds number of the flow in the pipe 17 is set to 230
Set to 0 or more.

The gas-liquid mixed flow through the pipe 17 is supplied to the nozzle 18
, And flows into the fine foam separation section 20. In the fine foam separation section 20, the liquid 10 is ejected into the liquid 10 together with the fine bubbles. Since the gas-liquid mixed flow is accelerated again when passing through the through-hole 16 of the nozzle 18, its static pressure is reduced, and the gas dissolved in the liquid 10 precipitates as fine bubbles. Further, the bubbles that have not been completely dissolved are also subdivided by the shearing force due to turbulence in the flow when accelerated in the through holes 16, and are released together with the liquid 10 as fine bubbles.

The liquid 10 jetted from the nozzle 18 to the inlet horizontal part 22 of the fine foam separation part 20 spreads in the liquid in the inlet horizontal part 22. The inlet horizontal portion 22 is
Any length may be used as long as the gas-liquid mixed flow injected from the nozzle spreads in the flow path of the inlet horizontal portion 22. The gas-liquid mixed flow injected into the inlet horizontal part 22 flows into the upright part 24 and rises.
At this time, the fine bubbles in the liquid 10 rise at a higher speed than the upward flow of the liquid 10 due to the buoyancy. Then, the gas-liquid mixed flow is bent again in the horizontal direction at the outlet horizontal portion 26. At this time, since the fine bubbles are rising in the upright portion 24 at a higher speed than the liquid 10, the fine bubbles are easily separated on the liquid surface of the liquid 10 when the flow is bent.
The length of the upright portion may be a length capable of obtaining a floating speed at which fine bubbles can be easily separated from the liquid 10 at the outlet horizontal portion 26, and preferably eliminates a useless floating period in the liquid. In order to reduce the number of bubbles, it is preferable that the length is not more than the length at which the maximum floating speed of the fine bubbles is obtained.

The micro-foam supply device of this embodiment has a total cross-sectional area of the throat portions 32, 33, a cross-sectional area of the inflow portions 34, 35, a cross-sectional area of the through hole 16 of the nozzle 18, and The relation of the sum of the cross-sectional areas of the throat portions 32 and 33 may be any as long as the following expression is satisfied. PAn <PGn (1) PGn (n is a natural number and corresponds to the number of inflow portions) is the pressure of gas, liquid, or the like flowing from each of the inlets 36 and 37 in FIG. PAn is given by the following equations according to the hydrodynamic continuity equation and Bernoulli's theorem.
35 static pressure. PAn = {1− (SAn ² SC) / (SA ² SBn ² )} P 1 + (δP + PB) ｛(SAn ² SC ² ) / (SA ² SBn ² )} (2) where SA is a throat Sum of cross-sectional areas of parts 32 and 33, SA
n is the cross-sectional area of each throat portion 32, 33, and SBn is each inflow portion 3
4, 35, SC is the sum of the cross-sectional areas of the through holes 16, P
1 is the total pressure of the inflow portions 34 and 35, δP is the pressure loss from the suction device 15 to the nozzle 18, and PB is the through hole 16 of the nozzle 18.
Outlet total pressure. Note that this equation corresponds to the case where the flow path is branched into an arbitrary number “n”, and the number of branched flow paths can be appropriately set so as to satisfy the above equation.

Accordingly, by setting the sizes of the inflow portions 34 and 35 and the through hole 16 of the nozzle 18 so as to satisfy the above equations (1) and (2), gas can be efficiently added to the liquid. Optimum conditions for pressure mixing and dissolution are obtained. Further, it is more preferable that the pipe 17 also serving as the pressurizing and mixing unit is capable of obtaining a gas-liquid contact time until the gas is dissolved and saturated in the liquid under pressure, and the gas-liquid contact time is determined by the volume of the pipe. The gas is dissolved up to the saturation point when the length of the pipe is somewhat longer. If it is not necessary to dissolve the gas to the saturation point, the pipe 17 may be short.

According to the fine foam supply apparatus of this embodiment, the fine bubbles formed in the liquid 10 are quickly and surely separated into the fine foam 28 and the liquid 10 by the fine foam separation section 20, and the fine foam in a good state is provided. 28 can be supplied efficiently. In addition, since the surfactant is sucked from the suction device 15 and injected into the flow path, unevenness in the drug concentration due to the pulsation of the pump is eliminated as compared with the case where a drug injection pump is used, and the surfactant is uniformly dispersed in the liquid. Surfactants can be mixed. Therefore, uniform fine foam can be stably produced.

Next, a second embodiment of the fine foam supply apparatus of the present invention will be described with reference to FIGS. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. In the fine foam supply device of this embodiment, a mixture of a surfactant and a liquid 10 is sent to a suction device 45 via a pump 14, a gas is suctioned into a flow path by the suction device 45, and gas-liquid mixing is performed. A stream is supplied to the fine foam separation section 20 via the nozzle 18. In the fine foam separation section 20, fine bubbles are separated as in the above embodiment.

The suction device 45 of this embodiment has a configuration in which only the flow path on the gas suction side of the suction device 15 of the above embodiment is provided.
A venturi tubular flow path having a throat portion 32 as a throttle portion provided at a central portion is formed. On the downstream side of the Venturi tubular flow path, an expanding portion 42 is formed, and the throat portion 3 is formed.
Immediately downstream of the throat 32, a cylindrical gas inflow portion 34 having a slightly larger inner diameter than the throat portion 32 is formed, and a gas inflow port 36 for mixing gas is opened in the gas inflow portion 34. I have. The gas inlet 35 opens into the air via a pipe 38 or is connected to another gas source.

In the fine foam supply apparatus of this embodiment, n = 1 in the above equations (1) and (2), and the sizes of the gas inlet portion 34 and the through hole 16 of the nozzle 18 are set so as to satisfy the condition. Thereby, optimal conditions for efficiently mixing and dissolving a gas under pressure in a liquid can be obtained.
The same effects as those of the above embodiment can be obtained by the fine foam supply device of this embodiment, and it is particularly suitable when the flow rate of the liquid is small.

Next, a third embodiment of the fine foam supply apparatus of the present invention will be described with reference to FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. The fine foam supply device of this embodiment receives and collects the liquid 10 separated by the fine foam separation unit 20 in the tank 50, supplies the liquid 10 to the pump 14 through the circulation pipe 52, and supplies the liquid to the suction device 55 again from the pump 14. ing.

The suction device 55 of this embodiment has a flow path separated like the suction device of the first embodiment. In this embodiment, the suction device 55 is branched into three. Among the flow paths in the suction device 55, the inflow portion into which the gas flows and the inflow portion into which the surfactant flows are the same as those in the first embodiment,
Further, an inflow section for supplying a liquid is provided. The inflow portion of the liquid is also provided slightly downstream of the throat portion of the flow channel, similarly to the first embodiment, and a liquid pipe 56 is connected to an inflow opening opened to the inflow portion,
The pipe 56 is provided with a flow control valve 58.

In this embodiment, the liquid 10 is consumed as fine foam, and the reduced amount is supplied from the pipe 56. The replenishment of the liquid 10 is manually performed, and is detected by a sensor or the like so that the liquid amount is within a predetermined range.
May be automatically controlled. In addition, since the surfactant is used for forming the fine bubbles, the concentration of the surfactant in the liquid 10 decreases as the bubbles are formed. Therefore, liquid 1
The surfactant is appropriately sucked into the liquid from the pipe 40 so that the surfactant concentration in 0 falls within a certain range. When supplying the surfactant, the concentration of the surfactant in the liquid 10 is detected by a sensor, and when the concentration becomes lower than a certain concentration, a pump or a valve is operated to supply the surfactant to the pipe 40.
To be injected into the suction device 55.

Next, a fourth embodiment of the fine foam supply apparatus of the present invention will be described with reference to FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. Similarly to the third embodiment, the fine foam supply device of this embodiment also includes the liquid 1 separated by the fine foam separation unit 20.
0 is received by the tank 50 and collected, supplied to the pump 14 through the circulation pipe 52, and supplied from the pump 14 to the suction device 55 again.

Further, in this embodiment, a suction device similar to the suction device 45 of the second embodiment is used. Then, in order to replenish the liquid 10 separated as the fine foam 28 and the surfactant, a pipe 62 is connected to each of the tanks 50, and the liquid 1 is supplied via a pump 56 and a chemical injection pump 58.
0 and the surfactant 60 are supplied.
When replenishing the surfactant, the concentration of the surfactant is detected by a sensor and the tank 5 is adjusted to a constant concentration.
You may make it inject | pour into 0. In addition, the amount of the liquid 10 may be controlled so as to automatically become a constant liquid amount by using a sensor.

Next, a fifth embodiment of the fine foam supply apparatus of the present invention will be described with reference to FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. In the same manner as in the fourth embodiment, the fine foam supply device of this embodiment also includes the liquid 1 separated by the fine foam separation unit 20.
0 is received and collected by the tank 50, the gas is mixed by the suction pipe 45 through the pump 14 by the circulation pipe 52, and fine bubbles are formed again.

In the case of this embodiment, in order to replenish the liquid 10 separated as the fine foam 28 and the surfactant, pipes 62 are connected to the circulation pipes 52, respectively, via a pump 56 and a chemical injection pump 58. Thus, the liquid 10 and the surfactant 60 are supplied. When replenishing the liquid 10 and the surfactant 60, a constant amount may be automatically controlled using a sensor or the like.

In the fine foam separation section of the present invention, the gas-liquid mixed flow flows in the horizontal direction below the substantially vertical upright section, and the flow path bends in the horizontal direction above the upright section. What is necessary is just to be able to separate fine foam and liquid at the bent portion. Therefore, the fine foam separation section can be arbitrarily set, such as a pipe in which a pipe is bent in a Z-shape or a box-shaped flow path in which horizontal and vertical flow paths are formed. Further, the position for supplying the surfactant of this embodiment may be connected to the pipe 17 through which the gas-liquid mixed flow flows in addition to the above-described embodiment, and may be connected in the middle of the circulation pipe 52 on the upstream side of the suction device 64. You may. Further, the throttle portion of the suction device may be formed by a Venturi tube, or may be rapidly narrowed in an orifice shape, and its shape is not limited.

[0034]

The fine foam supply apparatus of the present invention can form fine bubbles continuously and efficiently with a simple apparatus, and can supply high-quality fine foam in large quantities.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a fine foam separation section of a first embodiment of a fine foam supply device of the present invention.

FIG. 2 is a schematic diagram of a fine foam supply device according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a suction device of the fine foam supply device according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing a second embodiment of the fine foam supply device of the present invention.

FIG. 5 is a longitudinal sectional view of a suction device of the fine foam supply device according to the second embodiment of the present invention.

FIG. 6 is a schematic diagram showing a third embodiment of the fine foam supply device of the present invention.

FIG. 7 is a schematic diagram showing a fourth embodiment of the fine foam supply device of the present invention.

FIG. 8 is a schematic diagram showing a fifth embodiment of the fine foam supply device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid 12, 17, 38, 40 Piping 14 Pump 15 Suction unit 16 Through-hole 18 Nozzle 20 Fine foam separation part 22 Inlet horizontal part 24 Upright part 26 Outlet horizontal part 28 Fine foam

Claims (6)

[Claims] A microbubble forming device for forming microbubbles in a liquid is provided. The microbubble forming device is connected to an inlet horizontal portion formed of a substantially horizontal flow path, and an inlet horizontal portion is provided downstream of the inlet horizontal portion. A fine bubble separation unit including a vertical portion of a flow path formed in a vertical direction and an outlet horizontal portion provided downstream of the vertical portion and having a substantially horizontal portion, and the fine bubbles sent from the fine bubble forming device are provided. The fine-foam supply device in which the liquid containing is passed through the fine-foam separation section to be separated into the fine foam and the liquid. 2. The microbubble forming apparatus for forming microbubbles includes a throttle provided in a liquid flow path, a divergent part in which the flow path is gradually widened following the throttle, and A gas inlet formed slightly downstream and having a constant cross section,
A gas inlet provided in the gas inlet, and a pressurizer for pressurizing and mixing the liquid in the flow path provided downstream of the expanding portion and the gas flowing in from the gas inlet; 2. The fine foam supply apparatus according to claim 1, further comprising a mixing section, and an injection section provided on an outlet side of the pressurized mixing section to jet the gas-liquid mixed flow to the fine foam separation section. 3. The micro-bubble forming apparatus for forming micro-bubbles includes a branch point where the flow path is branched into a plurality of paths in the middle of a flow path through which the liquid flows, and at least one of the plurality of flow paths branched in parallel. A throttle portion provided on one side, an inflow portion located at a position downstream of the throttle portion and having at least an inflow port for allowing gas to flow, and a flow channel provided downstream of the inflow portion is gradually widened. A suction device including a widening portion and a merging point provided at the downstream of the widening portion or at the downstream thereof and merging the plurality of flow paths in parallel with each other. A pressurizing / mixing unit that pressurizes and mixes a gas-liquid mixed flow of gas introduced from an inlet, and an injection unit provided on an outlet side of the pressurized mixing unit and injects the gas-liquid mixed flow to the fine foam separation unit. The fine foam supply device according to claim 1. 4. The fine foam supply apparatus according to claim 3, wherein at least one of the inflow ports is for gas to flow in, and the other inflow port is for flowing in a surfactant mixed with the liquid. . 5. The fine foam supply device according to claim 1, wherein a surfactant is supplied into the liquid by a chemical injection pump in the middle of the flow path of the liquid. 6. A fine foam is taken out from an upper portion of the horizontal portion of the outlet, and a surplus liquid is taken out from a lower portion thereof.
The fine foam supply apparatus according to 2, 3, 4, or 5.