CA2113661C

CA2113661C - Method of and apparatus for injecting treating liquid into wood material and porous inorganic material, and method for destroying ray parenchyma cell walls and aspirated pit pair

Info

Publication number: CA2113661C
Application number: CA002113661A
Authority: CA
Inventors: Masateru Nozoki
Original assignee: Sumitomo Corp
Current assignee: Sumitomo Corp
Priority date: 1993-01-19
Filing date: 1994-01-18
Publication date: 1999-07-20
Anticipated expiration: 2014-01-18
Also published as: JP2557780B2; RU2128112C1; EP0607625B1; DE69329902D1; JPH06210606A; AU670142B2; DK0607625T3; ATE199001T1; AU5235993A; NZ250695A; DE69329902T2; EP0607625A1; CN1102801A; BR9400128A; FI940249A0; CA2113661A1; CN1035545C; EP1053841A1; FI940249A; MY110907A

Abstract

A method for injecting a treating liquid into a wood or stone material. The liquid is injected in an initial pressure-applying/injecting step in which the wood or stone material is immersed at ambient temperature in a treating liquid under an initial liquid pressure of 1 to 10 kg/cm2, and maintained at this pressure for a period of time.
Subsequently, the pressure is increased to a final pressure having a maximum value of 50 kg/cm2. Where wood is being treated, the pressure is raised in a plurality of steps of 5 to 10 kg/cm2 each, followed by a defined holding period. Where stone is being treated, the pressure is increased in a single step. Finally, the treated material is depressurized over a period of at least 20 minutes.

Description

-- 211~66 1 ~,~O~ OF AND APPARA~U~ FOR INJ~CTlNG TREATIN~-LIQUID INTO
~OOD HAT~RIAL AND ~GRGu~ I~ORaANIC MA~RIAL, AND h~.~OD FOR
D~ AO~lNG RAY PAR~NCRYMA C~LL ~AL~B AND A~PIRAT~D PIT PAIR

The prQsent invention relates to a method of and apparatus for in~ecting treating liquid such as resin into wood material and stone material. More particularly, the present invention relates to a method of injecting a treating liquid which gives the wood material high rot resistance, insect resistance, ant resi6tance, mold resistance, flame resi6tance, dimenslonal st~bility, and increased strength, and which gives the stone material increased acid resistance. The present invention also relates to a method of destroying ray parenchyma cell walls and aspirated pit-pairs.

Hitherto, various methods have been used such as injecting treating liquids into the wood material, as heat-treating and applying pressure on it, as pouring liquids into it after boiling, for making it highly flame resistant, rot resistant and insect resistant, and for giving it high dimensional stability and increased strength.
The treating liguids have been injected into the wood material by applying thereupon pressure right up to a specified pressure in a short time while maintaining that pressure for a long period of time. In this case, though dep~Aing on the kind of wood material used, the injection of the treating liquid has been generally carried out at a pressure not more than 15 kg/cm2 because injection carried out above this pressure causes the wood material to deform such as to warp, bend, or to ~e~ - ~h~nner.

~A

211366 1 '' As such a treatment method, there i6 known a wood treating process di6closed in USP 4,194,033 (Motai). With this disclosed process, wood i8 heat-treated and boiled so that film holes are opened by pressure and temperature. Also, as described in USP 3,693,584 (Barnett), there is a proposed method by which pressure is slowly intermittently raised for injecting treating liquid. Note that USP 3,693,584 (Barnett) discloses an apparatus by which pulse pressure is applied to open and close wall holes for in~ecting treating liquid, aiming to, e.g., shorten the treatment time and inject the treating liquid into the wood core 6ufficiently. Further, typical one of treating-liquid in~ecting apparatus is disclosed in USP 3,895,138 (Sewell).
In recent years, deterioration of h~ ngs made of stone material caused by acid rain has become a problem in Europe.
Various measures have been taken to protect the stone material from acid rain, such as applying the treating liquid to the stone material, and taking advantage of the properties of the stone material itself, such as the property of marble to neutralize acid water which comes in contact with its surface.
The wood material generally has many groups of cells as shown in Fig. 8. Between each cell is a 6tructure consisting of a wall pit-pair 1 scattered about forming wall pit 2 as shown in Fig. 9(a). At the center of the wall hole 2 i6 a hyperplnstic portion, called a torus 3. The torus 3 is ~uL~unded by a thin mesh-like pattern (margo). In the wood material having this kind of 6tructure, in the process of processing the wood material into heart wood and the like, the wall pit wall i8 drawn toward one of the pit opPn~ngs, so that the torus 3 blocks the pit opening. The wood material in this condition is said to have an aspirated pit-pair (Fig. 9(b)).
When the wood material has an aspirated pit-pair, which is seen in the heart wood in many cases, the torus 3 blocks the ~, , '- 211366 1 pit 2. The wall plt 2 in the heart wood as well a6 those in the sap wood are al60 ~locked by the toru6 3. For thls reason, in order to spread the treating liquid thLGUyhOUt the wood material, lt is necessAry to de~L,vy the torus 3 whlch blocks the pit op~n~ of an aspirated pit-pair, or to de~LL~y the cell wall itself, 80 that the treating liquid can permeate into ad~acent cells.
In order to ~e~ y the torus 3 to those at the center of the material, an applled p~e6~u~e of 30 kg/cm2 has been requlred using the ~n~el.L~QnAl treating-liquld in~ectlng methods. u~we~e~ as descrlbed above the materlal hAs been deformed at an Appl~e~ ~L~F_ ~rê of 15 kg/cm2 or more. As a result, it has been nece~-ry to carry out the in~ection at a low pressure whlch does not cause deformatlon Or the ~aterlal.
Con-equently, there has not been ~ oUJ~ pressure to de~L,vy the torus 3 adequately and in~ect sufficiênt treating liquid into the interior of the wood matêrial.
The wood treating ploce6s using heating and boiling as A1~clo~~' ln USP 4,194,033 (Motal) remarkably deteriorates the ~L en~Lh of wood. Also, hecAl~e the pre~sure for pressurization is as low as 1.5 kg/cm2 to 2 kg/cm2, the external pressure is in bAlAnce with gases in the treated material and hence the treating liquid cannot be in~ected into the wood core (for a JArA.~se red pine of 250 x 250 x 2000 mm, a maximum a~ e value of the penetration depth i6 85 mm: see Table 1).
Further, while USP 3,693,584 (Barnett) describes pressurization, the ~aximum raised p~e~Duhê i6 generally on the order of ~5 kg/cm2 ~6 ~entloned above and, therefore, the treating liquid cannot be in~ected into the wood core even if the pressure is slowly intermittently rai6ed. Thi6 is also apparent from the fact that one ob~ect of USP 3,693,584 (Barnett) i6 to 6ufficiently in~ect the treating liquid into A~-~- 21 1366 1 the wood core. USP 3,693,584 (Barnett) intends to inject the treating liquid by increa~ing and decreasing the presgure-applying force with a short period, i.e., to improve quality of the injection treatment from the different stAn~roint from that of the present invention.
on the other hand, particularly for broadleaf trees, pres~ure i~ applied to the wood material to a predetermined pressure. For this reason, impuritie~ such as tylose get clogged in the ve66el~ ng it extremely difficult to in~ect the treating liquid to the central portion of the material.
In addition, the ~tone material has been only protected at the ~urface because the treating liquid has only been applied to the surface thereof, and because of the nature of the ~tone material $tself. As the ~tone material was exposed to acid rain over a long period of time, its acid resi6tance decreased, so that the -AF~res taken against the acid rain hec~ - ineffective. As a result, the acid rain permeated to the interior, and the stone material was eaten away from the interior, resulting in a powdered interior and the like.

The present invention i6 intenAe~- to overcome the above-de~cribed problems and has as its ob~ect the provision of a method of and an apparatus for in~ecting a treating liquid into wood material and porous inorganic material so that the treating liquid ~preads throughout the interior thereof, without deforming the wood material, stone material, and other material~ to be treated. The present invention has as another ob~ect the provision of a method of destroying ray parenchyma cell wall~ and aspirated pit-pairs.

A
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To achieve the _bove ob~ects, the present invention provides a method of destroying ray parenchyma cell w_lls ~nd aspirated pit-pair6 of conifer6, and in~ecting treating liguid into conifers, the method compri6ing ~n initial pressure-applying/in~ecting step of liguid-pressurizing the treated wood material at the normal temperature under pLe~ure in the range of 1 to 10 kg/cm2, and holding the r_ised pressure for at least 10 minutes to in~ect the treating liguid into the tr~Ache~ of the treAted material a treating-liquid in~ecting step of, after QlAr~e of the time holding the above ralsed pressure, stepwisQly pressurizing the treated material at the normal temperature up to the ~inal applied ~ E-~re having a maxlmum value of 50 kg/cm2 with intervals of 5 to 10 kg/cm2, And holding the rai6ed pr~5~UL2 in each of the pressure-applying stages for at lea6t 10 minutes to in~ect the treating liguid under pres6ure into the treated wood while dissolving the gases remnining in the treated wood in the treating liquid, and a pressure-removing 6tep of depre66urizing the treated wood from the fin_l applied pressure to the atmospheric pre66ure for a period exten~e~ to at least 20 or more minutes to ~eve~ the treated wood from being broken due to abrupt ~YpAn~on of the gases di6solved in the treating liquid in~ected into the material. Preferably, a ~Le6DULe re~c~ n~ 6tep of de~res~Lizing the treated wood down to at least the atrr ~eric preF--~re or below, and holding the ~ c~ eFF-~re for at least 20 minutes to purge gases out of the treated wood may be inter~z_e~ before the initial ~i e~DUL a applying/in~ecting step.
Al60, in a method of de6troying ray parenchyma cell wall6 and aspirated pit-pairs of broadleaf trees, and in~ecting treating liquid into conifers, the method compri6es a pre6~u.e .~ -c~n~ 6tep of dep,e~u~izing the treated wood material down to at least the al -.p'-~ric pre66ure or below, A

, and holding the .e~ ceA pre66ure for at lea6t 30 minutes to purge ga6e6 out of the treated material, an initial pressure-applying/in~ecting step of llquid-pres6urizing the treated wood at the normal temperature under pressure in the range of 1 to 10 kg/cm2, and holding the rai6ed pressure for at least 20 minute6 to in~ect the treating liguid into the tr~h~ A of the treated ~aterial, a treatlng-liquid in~ecting 6tep of, after el~p-e of the time holding the raised pressure, 6tepwi~ely pre66urizing the treated wood at the normal temperature up to the final applied ~,eg~u,e having a maximum value of 50 kg/cm2 with interval6 of 5 to 20 kg/cm2, and holding the rai6ed ~Le~u'~e in each of the presDu.e applying 6tage6 for at lea6t 10 minute6 to in~ect the treating liquid under pres6ure into the treated wood while dis601ving the gases remaining in the treated wood in the treating liquid, and a pres6ure-removing 6tep of depre66urizing the treated material from the final applied pre66ure to the at ~ ric pre66ure for a period extenAeA to at lea6t 20 or more minutes to ~e~ht the treated wood from being broken due to abrupt p~n~ion of the ga6e6 dissolved in the treating liquid in~ected into the treated wood.
Further, co~cerning a method of in~ecting treating liquid into 6tone material6 in the pro~~ t invention, the method compri6es a pre6~u,e ,~uc~ng 6tep of depre66urizing a treated material down to at lea6t the atmcE~-ric pres6ure or below, and holding the re~uce~ ~e~u~a for at least 60 minute6 to purge ga6e6 out of the treated material, an initial pre66ure-app~ying/in~ecting 6tep of liquid-pre66urizing the treated ~aterial at the nor~al tem~eL~Lu~e under ~r~_E-~re in the range of 1 to 10 kg/cm2, and holding the rai6ed pre66ure for at lea6t 60 minute6 to in~ect the treating liquid into crack6 insidQ the treated material, a treating-liquid in~ecting 6tep of, after el~rEe of the timQ holding the rai6ed pre66ure, pres6urizing the treated material ~t the normal temperature up to final applied pre66ure having a maximum value of 50 kg/cm2 at one time, and holding the final applied pre66ure for at least 30 mlnutes to in~ect the treating liquid under pre66ure into the treated materlal while dl6solving the ga6e6 remaining in the treated material in the treating liquid, and a pres~u a ,~moving 6tep of depre6~urizing the treated material from the final applied pLe~u a to the atmo_,~?ric pre6sure for a period ext~nAeA to at lea6t 20 or more minutes to r.L the treated material from being broken due to abrupt eYrAn~ion of the ga6e6 di¢601ved in the treating liquid in~ected into the treated ~aterial.
Preferably, the treated material i6 pre66urized under dynamic pre66ure by using a pres~u,e applying pump of delivery constant type. When treating wood material6, the treating liquid may be a cation-ba6e treating liquid prepared by emul6ifying plant oil or mineral oil with a cationic 6urfactant. On the othèr hand, when treating 6tone materials, the treating liquid may be one cont~A~n~ng 6ilane monomer6 a6 a main com~onenL.
According to the method of in~ecting treating liquid rel~ted to the present invention, e6tabl~ ng an initial pre6~ù~e applying/in~ecting 6tep not only to facilitate the6e operation6 later but al60 to remove the p~_Q-~re to that of the atr~ e th~ougl. a ~Y-~a ~ ~lng tank at the maximum of 50 kg/cm2 without bre~ng the wood material in ac¢ordance with the type of material treated and it6 interior 6tructure, is e~fective in making po~6ible the treatment of in~ection at the high pre66ure of 50 kg/cm2. Therefore, in~ecting treating liquid into the raw wood materials up to the heart wood, which wa6 very difficult u6ing the cor~r~ n~l method6, and in~ecting treating liquid sufficiently to the Ce.~L~1 portion of the 6tone material, which in~ection it6elf wa6 not carried ~A

out u6ing the cor.~el.~lonal methods, become posslble.
Furthel -~e, in ln~ectlng treatlng-llquld lnto the mnterlal, the treatment i8 possible at the normal temperature (0 to 40~C). As a result, this is also effectlve in the efficiency of work, becau6e such extra work can be omitted, as creosote treatment that treating liguids are in~ected after heat-treated up to about 90~C, or making the in~ection easy beforehand by heat-treating and boiling the material.
Accordingly, the wood material has greatly increased rot re6istance, insect re6istance, ant resi6tance, and mold resistance increasing the lifQ Or the wood. In addltion, in~ecting treating liquid, having no possibility of ~ -ng, to the cenL.al portion ~e~en~8 crack~ng from o~a~Ling for a long period of time, allowing a hlgh ~ onal stablllty to be ob~A~ns~. Further, uslng a flame-resi6tant treating liquid therewith in~ects the treating liquid thG~ouyhly to the central portion, 80 that the wood material treated by the present method has high flame resistance and dimensional stablli~y, allowing it to be u6ed in a variety of applicatlons- In addltlon, by the ~P~nt method, the posslbllity of in~ecting treating liquid is w~ene~ even to many kind6 Or wood which had been regarded as difflcult to in~ect and therefore which could not be treated, and thu6 the use of whi d had been limited. M~eo~e" the increased life of the wood material and the increa6e in kinds of wdod which can be treated help stop the unpl~nne~ cutting of tropical forests, a problem in ~ecLI.L years, thereby making the method extremely useful from the viewpoint of forest protection.
The stone materlal can also be protected from damage caused by acld rain, 80 that its yL~c~ ~les are not deteriorated. The outside walls of h~ ng8 can be protected from destructlon c~a~ by acid rain, a seriou6 problem ln the reglons, 6uch a6 ~u.ope, whlch have many bull~ngs bullt of 'A
, 211366 1 ~
stone material. In other word6, according to the present invention it will not be necessAry to prohibit the use of marble and other 6tone materials for the out6ide walls of b~ ngs. The invention not only y~e~er.~6 ~ -ge6 to the stone material from oc~uL,ing, but al60 i6 very useful for preservlng a nation' 8 culture and for environmental protection.
According to another a6pect, the pre6ent invention al60 provides an apparatu6 for in~ecting treating liquid into wood m~terial6 and po.~s inorganic materials, the apparatus comprising a pre~6urQ ves6Ql for accommodating a trested material in a rE~l~ 6tate, a ~1 a6~ùLizer for deprcEs~rizing the pressure vessQl, a liquid pressurizer of delivery constant type for pres6urizing the pressure vessel under dynamic p~L~6uLe, and a ~L~g6uLe ,. ~ing apparatu6 con~ected to the pres6ure vessel and cont~n~ng a ga6 pressurized to the 6ame pressure as the treating liguid in the ple~6uLe ves6el, ~or relea6ing the ga6 to the a~ -~yhere to thereby L.--~ve the yLC65u~ e in the p~e66uLe ve6sel. Preferably, the pre66ure-removing apparatu6 may compri6e a pre66ure-removing tank which is ccr.r.e_~ed to the pressure vessel and is cont~n~g a gas pressurized to the same pre66ure a6 the treating liquid in the yL~ 6~re ve66el, and a pre6su~a ~e~oving valve which i6 ccr~eYLed to the pre66ure-removing tank and is ~ye..ed and closed to ,. -~ the y~C~u~ in the yLc~.uLe ves6el thl~u~l-the ~Le6DU~e removing tank.
Further, according to the present invention, in a method of in~ecting treating liquid into wood material6 and porou6 inorganic material6 by u6ing a treating-liquid in~ecting apparatus which compri6es a pre66ure ve66el for accommodating ~ treated material in ~ re-le~ 6tate, a dep~e6~u,izer for depre66urizing the pre66ure ve66el, a liquid pre66urizer of delivery con6tant type for pre66urizing the pre66ure ve6sel under dynamic pressure, and a pressure-removing apparatus which is connected to the pressure vessel and containing a gas pressurized to the same pressure as the treating liquid in the pressure vessel, and is releasing the gas to the atmosphere to thereby remove the pressure in the pressure vessel, an expansion speed of the gases which are dissolved in the treating liquid inside the treated material accommodated in the pressure vessel is suppressed by controlling the pressure-removing apparatus so as to remove the pressure in the pressure vessel down to the atmospheric pressure for a period extended to at least 20 minutes, making the gas which has a smaller molecular structure than the treating liquid discharged from the treated material earlier than the treating liquid. Preferably, the pressure-removing apparatus may comprise a pressure-removing tank which is connected to the pressure vessel and containing a gas pressurized to the same pressure as the treating liquid in the pressure vessel, and a pressure-removing valve which is connected to the pressure-removing tank and is opened and closed to remove the pressure in the pressure vessel through the pressure-removing tank. In this case, an opening degree of the pressure-removing valve is controlled so that the pressure in the pressure vessel is removed down to the atmospheric pressure for a period extended to at least 20 minutes.
The apparatus prevents air expansion from breaking the material while pressure is being removed, allowing the treating liquid to be injected into the central portion of the material.
Having thus described the invention, reference will now be made to the accompanying drawings illustrating preferred embodiments and in which:
Figs. l(a) through l(c) illustrate graphs showing the reduction and application of pressure when the treating-~'A ~

2 1 1 3 6 6 1 ~

liquid injecting method of the present invention is appliedto conifers (lodge-pole pine);
Figs. 2(a) through 2(c) illustrate graphs showing the reduction and application of pressure when the treating-liquid injecting method of the present invention is applied to broadleaf trees (red oak);
Figs. 3(a) through 3(c) illustrate graphs showing the reduction and application of pressure when the treating-liquid injecting method of the present invention is applied to stone material (marble made in Italy);
Fig. 4 illustrates the internal structure of the conifer;
Fig. 5 illustrates the internal structure of the conifer;
Fig. 6 is a cross-section illustrating the condition of the wood material after it has been treated with the treating-liquid injecting method of the present invention, and that after it has been treated with a conventional treating-liquid injecting method;
Fig. 7 is a block diagram illustrating the arrangement of the treating apparatus for implementing the method of the present invention;
Fig. 8 is an enlarged sectional perspective view illustrating the structure of the wood material;
Figs. 9(a) and 9(b) are cross-section of the wall pits in the wood material structure;
Figs. lO(a) through lO(d) illustrate the injection depth of the treating liquid when the treating-liquid injecting method of the present invention is applied;
Figs. ll(a) through ll(c) are tables illustrating the test data in the cases of Fig. 1 to 3; and ~A ' 211~66 1 -~

Figs. 12(a) through 12(d) illustrate cells of the wood material before and after the treatment of the present invention is carried out.
Similar numerals in the Figures denote similar elements.
Fig. 1 shows graphs showing the reduction, application and removal of pressure in the first embodiment of the present invention when the method is used to inject the treating liquid into the conifer. Further, Fig. 1 is the illustration of the lodge-pole pine treated with injection.
Figs. 4 and 5 each illustrate the structure of the conifers. Fig. 6 compares the condition of the wood material after it has been treated using the treating-liquid injecting method of the present invention, and after it has been treated using a conventional treating-liquid injecting method. Fig. 7 is a block diagram showing the arrangement of the apparatus used for implementing the present method. Fig. 10 illustrates the injection depth of the treating liquid when the present invention is applied.
In the present invention, the treated material 11 which is stored in a pressure vessel 12 is treated as follows:
first, the pressure is reduced by a pressure-reducing vacuum pump 13; next, from a treating-liquid reservoir 16 via a treating-liquid measuring reservoir 14, the treating liquid is injected with the application of pressure by a liquid pressure-applying pump 15 of delivery constant type.
Then, the pressure is removed from the inside of the pressure vessel 12 via a pressure-removing valve 19 and a pressure-removing tank 18.
The conifers generally have the structures shown in Figs. 4 and 5. For this reason, it is necessary to destroy the ray parenchyma cell walls and aspirated pit-pairs to inject the treating liquid to the central portion. In the present iA ~

method, the pressure 18 gra~ally applied from a low pressure to the material to be treated, so that the pressure difference beL~een the internal and external portions of the wood material is mainta1ne~A~ which is large enough to desL~oy the torus 3, but not too large to deform the wood material. Each toru6 3 i6 then A - F L,oy~d by the pres6urQ of the treating liquid, allowing the liquid to permeate sufflciently to the internal portion of the wood matQrial.
First, after the treating liquid is in~ected into the surface cells (both cells whose cross-section is ~YpoEe~A. to the 6urface _nd which are near the surface), the ray paLenc~.yma cell walls at the outermost portion and the aspirated pit-pairs are desL~o~cd, and then the pressure in the trache~A 21a i6 made equal with the external pressure.
The pressure in the tra~-he~ 21b, 21c, and the like is m_de egual with the external ~.es6u~e as each torus 18 surce66ively de~L,v~ed to those in the heart wood. In this case, the pressure is transmitted t~uyl- very narrow gap6 or small holes. Accordingly, it i~ ~ecess-ry to increase the pre6sure for h~gh~r efficiency, but a suAAPn increA6e in pressure Ça~ the material to hec- - th~nn~r and become deformed.
Con~esuently, in the present invention the pLe6~u~ e is increasQd ~u~ eFs~vely in ~teps 60 a6 not to thin and deform the material.
In the pres~u~a ~ c~ng step of the present invention, _ treated material 11 is stored and se-leA in a pressure vessel 12 comprising the apparatus illustrated in Fig. 7 (step 1 of Fig. 1, whlch will be abbreviated to S1 hereafter). Then as shown in Fig. 1, the p~2F ~re of the material is temporarily re~A.~ce~A to 760 mmHg by a ~Le6~u~e reA~c~ng vacuum pump 13, with the material mainta~ne~A~ at thi6 ~Le6~uLe for about 20 minutes, in order to L~'-Ve as mu¢h air ~rom the material as possible. -A

21 1~66 1 The depressurizlng process i6 not limited to the pressure of - 760 mmHg, but may be performed under the atmospheric pressure or below. For conifers, the pressure-reA~o~g plocess itself is not neces6~rily required. Alt~ol~qh the pre6sure level ~ay be at the atmospheric pressure or below, a very long treatment time which is in ~YcesF of the practical range would be neeAe~ lln~P6s the treated material i6 depressurized down to - 600 mmHg or below. on the other hand, if the treated material i~ depres6urized down to - 600 mm~g or below, the treatment time would be shortened, but it would be reguired to ~ a a F~~l~ng ability or the eq~ nt and the performance of the vacuum pump, resulting in poor economy. If no pre55 ~e ~e~ clnq ~YOCCS8 is performed, it would be required to take a longer time for each of r~h-eguent steps l~c~ce of the effect of gases existing in the treated material. From the bal~nce bcL~etr. the treatment time and the n~ceS~ry equipment, therefore, thi6 embo~ ~ employs the pres~u~e ,el.~ nq ~ocass under - 760 m~Hg as the pressure-reA~Cl ng step.
The next step is the pressu~e applying step. In the initi~l pres~u,e applying/in~ecting step, pressure is applied on the ~aterial at be~eO 0 kg/cm2 and 10 kg/cm2 by a liquid pressuLe applying pump 15 of delivery constant type (S2).
BesidQs, in the present embodiment, this step is done at beL~L~r. 0 and 5 kg/cm2. In this case, each portion of the material in the pressure ve6sel 12 is 6ub~ected to the same pre66ure in aacordance w~th Pa6Ca1'~ law. The materlal is maint~lneA at this pressure for about 20 minutes. Unlike a pump of pressure c~n~ant type which has been convcl,Lionally used for in~ection under pressure, this liguid pressure-applying pu~p 15 of delivery constant type operates in such a manner that if the setting pressure is set to 5 kg/cm2, for example, the pump cont~nuo~ly supplies the treating liguid at <A -'' a cert~in flow rnte under pressure in the range of O kg/cm2 to 5 kg/cm2 to the pressure vessel 12. When the interior of the pre6sure vessel 12 reaches the setting pre6sure, the pump throttles the delivery rate 60 as to maintain the setting pressure. The llquid pres~uLc applying pump 15 of delivery constant type is also different from the pump of pressure constant type in that a ~Lu,.. pipe for ~eLu~..ing the treating liguid from the pump to the tank to remove the pressure cefifiively applied i6 not provided.
In this embodiment, when the pressure vessel 12 is filled with the treating liguid and the liguid pres~e applying pump 15 of delivery con~Lant type still further cont~ n~8 to supply the treating liguid, the ~L2 ~-~re in the pressure vessel 12 is raised because the treating liguid supplied to the pressure vessel 12 has no exit to ese~re thereth~Guyl.. As the pressure rises, the treating liguid is in~ected into the treated wood materi 1. At the same time, ray parenchyma cell walls and wall pits of the treated material ~re broken. The in~ection of the treating liguid and the destruction of the ray parenchyma cell walls mean that the volume of the pressure v~FFe~ 12 is e5~ Lially increa6ed, and hence the pressure in the pressure vessel 12 is re~ure~. In ~r~yc.r.Fe to a pressure drop, the treating liguid is further in~ected into the treated wood and the pressure is further raised. This pressure rise cAur-~ another in~ection of the treating liquid and another destruction of the ray pa~e,.~ ma cell walls. Thereafter, the pLoces8 is cont~ue while the pressure is re~U~e~ and then raised. Thus, in this . hg~ -nt, the pressure for pressurization is gr~ y raised with repeated up and down of the pressure. When the y,e&~u~e for pressurization re~rh~s the setting pres6ure, the delivery rate of the treating liquid is throttled 80 as to maintain that ~L~F !~re. Upon no further in~ection being ~ d under that pre66ure, the treating ~A

21 13 6 6 1 ~
~.

liquid 6top6 m~v.- -nt toward the pre6sure ve66el 12 and the pre66ure for pressurization ce~s~F to risé. The process is no longer ~o~L666ed in such a condition and, therefore, the pre66ure for pressurlzation is rai6ed to a next 6tage. Stated otherwise, in this embodiment, the treating li~uid i6 moving in the pressure ve66el 12 at all times to create dynamic pressure therein, and the treating liquid is in~ected into the treated material under 6uch dynamic pres6urQ, By col.LLa6t, in the convention~l pump of pres6ure con6tant type, when the 6etting pres6ure of 5 kg/cm2, for example, i6 reached, movement o~ the treating liquid from the pump to the pressure ve6sel is 6toppe~, creating static pressure in the pressure vessel. In other words, the pressure i6 linearly raised and comes to a 6tandstill at the setting pres6ure. Accordingly, the in~ection of the treating liguid is harder to develop than the in~ectlon thereof under dynamic pres6ure like this embodlment. Furthermore, when the interior of the pressure vessel reaches the setting pressure,- the valve i6 6witched to ~e~UL~ the treating liquid from the pump to the tank thlu~yl. the ~eL~L~I pipe for removing the pressure ~Yce6~ively applied. Because of this valve switching operation, it i6 difficult to make conLLol to 6upply the treating liquid again to the pressure vessel 12 immedi~tely in ~DpOn~9 to a 6m~11 pres6ure ohange in the ~,~sF-~re ves6el 12.
On the conL,ary, in this embodiment u6ing the pu~p of delivery constant type, since the ~e~u,e vessel 12 has no exit to e~c~pe theret~Iu~gh and the pump i6 operating at all ti~es, urging the treating liquid to be delivered, the treating liquid can be ,e u~plied i~mediately in ,~v~o~re to pressure change. A pressure of O to 10 kg/cm2 is large ~nongh to destroy each torus 3 and the like. As a result, although when the material is maint~ned at this pre66ure with the treating liquid being in~ected into the 6urface cells, not ~11 of the A

ray parenchyma cell w_118 and aspirated pit-pairs are de~L,oyed, a portion of them is de~oyed, allowing pressure to be transmitted to the cenL,al portion. At this relatively low pressure of a maximum of 10 ~g/cm2, the wood materlal itself is not deformed. The lnitlal pre66ure-applying/in~ect$ng step which uses the pump of delivery conOLant type i8 one of ma~or features of the present invention. By carefully performing thi6 step for an extenAeA
tlme, the treating liquid penetrate6 lnto the wood core, and the applled pres6ure is also transmitted to the wood core, en~h~ ~ ng the treatlng liguid to be effectlvely in~ected in the F~h~equent treating-liguid in~ecting step. Thus, this step i6 not ~ust a fir~t ~tage of the r'b~P,~ent stepwlse pressure applic_tion, but has a meaning as a p~e ~oc~s for the ~equent stepwi6e pressure Arpl~cAtion under high pressure.
on the other hand, thl6 step is required to be carrled out under such a level of pressure as the treated material will not be de~L,vyed. Theoretically, therefore, the pre6sure applied in thls step c_n be ral6ed up to the limit pressure until which the treated material is not desL,oyed, i.e., 15 kg/cm2. However, this step is carried out below 10 kg/cm2, i.e., lower than the limlt ~La~6u~e, ln the present invention.
The reason is as follows. 15 kg/cm2 ,e~ ent6 the limit pressure at which de6truction of the treated wood i6 v~ ly conrirmed. T~o~ng at the material on a microscopic scale, there o~ul~ collApFe of the wood when in ~'C~vG of 10 kg/cm2.
If the wood i6 collApse~, the treating liquid is not in~ected into the cell6 of the col 1A~P6~ region, and conrequently the portions not filled with the treating liquid are left in the material. If the ~Loce68 comes into the 6~hsequent treating-liquid in~ecting step under such a condition, the non-in~ected portions of the materi_l cannot withstand the high pressure applied in the treating-liquid in~ecting step and thus the i ~ ''~

wood would be destroyed, because the non-in~ected portlons are not s~en~h~n~ by the treating liquid and the appl$ed pre88Ure i8 not transmitted to the lnterior of the m~terial.
In the present invention, therefore, a maximum vslue of this step is set to 10 kg/cm2. Particularly, in thi6 embodiment, the maximum value is set to 5 kg/cm2 with a sufficient allowance.
The next step is the treating-liguid in~ecting step. In the present embodiment, as 6hown in Fig. 1, the pressure is increased stepwise from a pressure of 0 to 5 kg/cm2 of the initial pressule applying/in~ecting step until the final 45 kg/cm2 stage of pre~6ure application (83-S6). In this embodiment, the y.ess~se is increased to 15 kg/cm2, 25 kg/cm2, and 45 kg/cm2. The final applied pressure can be set to 50 kg/cm2 at -Y~ . Depen~1nq on an imy~ nt of the pressure resisting eq~ - ~, the final applied pressure can be set to h~qh~r pressure, e.g., 70 kg/cm2. HOWeV~L, according to the method of the present invention, since the treating liquid can be in~ected into the center for al ~ ~ all kinds of trees under the pressure of up to 50 kgjcm2, applying h ~ qh~r pressure than 50 kg/cmi is meaningless. Note that the maximum value of 50 kg/cm2 represents the pump setting pressure and of course includes an error of about 10%.
Accordingly, when the final applied ~LC~u~e of 45 kg/cm2 is applied in this embodiment, the ~ e~8~Lc of approxlmately 50 kg/cm2 may be in fact applied to the treated wood.
Further, the maximum applied pressure is changed to an ayyLGp~iate value der~n~nq on the kind of the wood material.
Specifically, for lodye ~ole pine into which it is hard to in~ect the treating liquid, the maximu~ applied pressure i8 set to 45 kg/cm2 like this embodi~ent, but for Japan cedar into which the treating liquid is easily in~ected, the maximum applied pressure of 30 kg/cm2 is sufficient.

A

First, the pressure i6 increa6ed 6 to 15 kg/¢m2 (S3).
Since a pressure Or 5 kg/cm2 has been applied in the initial pressu,e applylng/in~ecting step (S2), there i8 a relative pres6ure dlffe~nce of 1 to 10 kg/cm2 beL~ee,. the internal and external portions of the wood material at the time when the pre88ure i8 inGreased to 15 kg/cm2. Tho~lgh Aepe~ g on the type of wood ~aterial, the torus 3 is ~r~ y destroyed when a pressure of 2 to 5 kg/cm2 is applied to it. Accordingly, in the first stage of the treatlng-liquid in~ecting 6tep, a greater number of aspirated pit-pairs, mainly those near the outer portion of the wood material, are de~L~oyed. The mater$al is again maint~ neA at 6 to 15 kg/¢m2 for about 20 minutes. ~ere the pressure ~n~lAp the pressure vessel 12 rises with up and down beL~eel. 6 and lS kg/cm2 to 15 kg/cm2 which is provided, keep~ng the ~n~Ae of the vessel unfixed in pressure. For this reason, in the same way as it is described abovej the pressure is transmitted th~u~l- destroyed ray parenchyma cell walls and aspirated pit-pairs, allowing the wood material to be sub~ected to a pressure of 15 kg/cm2 to its inner portion.
In the treating-liguid in~ecting step, the pressure is further increased when a~pLv~Liate while in each pressure-applying stage the material is main~ P~A at a part1rl~lAr e~u~e for a certain period of ti~e. That is, in the ~Frnt step pressure is further applied to the wood material at 16 to 25 kg/cm2, 26 to 35 kg/cm2, and 36 to 45 kg/cm2, each for 20 minutes untll the rinal ~tage of pre6sure application (S4-S6). The relative yL~_s~re difference which oc~u~
between the internal and external portions of the wood material in each 6tage fi~cc~6~ively de6Lloy~ the ray parenchym~ cell walls and the aspirated pit-pairs.

Fig. 10 show6 s~ce~sive changes in in~ection depth of the treating liguid resulted when the pressure is 6tepwisely ~A ~

raised a6 mentioned nbove. Fig. lO(a) shows the in~ection depth of the treating llquid in the initial pre6sure-applying/in~ecting step. For the conifer, the treating liquid is first in~ected into cell6 exi6ting in the wood surface.
The re~n~ are that cell section6 are eYro~e~ to the surface of the conifer, enabling the treating liquid to be in~ected into the surface cells, and that the cell6 to which the treating liquid has been in~ected have h ~ gh~r ~ .e resistance than the cells to which the treating liquid has not yet been in~ected. The latter fact i6 attributable to that the volume of liquid is less changed than the volume of ga6 with ~e~pecL to pressure. Therefore, the cells to which the treating liquid ha~ been in~ected are not bLOUy21t into cell Lu~u,e even when pressure i~ applied thereto externally, because a volume change of the in~ected liquid is small. On the other hand, for the cells to which the treating liquid has not yet been in;ected, gases in the cells are compressed upon the pres6ure applied thereto externally to such an extent that cell wall6 can no longer resist a change in the volumes of s- ~es~ed gases, and the cells are lu~L~,ed even with the 6ame pressure applied. Stated otherwise, to apply pres6ure not lower than 15 kg/cm2 in the ~h~squent treating-liquid in~ecting step, it i6 required to in~ect the treating liquid into the surface cells 80 that tho6e cells have sufficient pressure resistance. Thus, the initial pressure-applying/in~ecting step in the present invention i6 not ~ust a fir6t 6tage of the stepwise ~e~u,e application, but an ~ ant step for enabling the F-~h-equent high-pressure proce6s to be achieved. Under the pres6ure applied in the initial step, once a certain amount of treating liquid is in~ected, the treating liquid cannot he in~ected in the amount ceeding the above one, even if the in~ection is cont~n~le~

~A

. .
for an exten~e~ time. Therefore, the p~oce86 i8 Advanced to a next 6tep for raising the pressure by one stage.
Fig. lO(b) shows the first stage of the treating-liquid in~ecting step in which the ~e~u,e i6 raised to in~ect the treating-liquid into a ~eep~r region than in the previous step. But, ~ec~re the pressure re~-hos a limit in thi6 stage too, the pressure is further rai6ed by one stage.
Likewise, in Fig. 10(c), the treating liquid is in~ected into an ever ~ee ~r region than in the previous stage, but the pressure reA~h~ a limit. Then, the interior of the pressure vessel is pressurized to the final applied pressure.
Under the final applied pressure, the treating liguid i8 in~ected into the wood core tFig. 10(d)). Whether the treating liquid has been in~ected into the wood core or not is ~udged by comparing the amount by which the treating liguid can be in~ected on calculations with the amount by which the treating liquid has been actually in~ected. On this occasion, the amount by which the treating liquid can be injected on CAIclllAtions i6 determined by subtracting the volume of wood portion and the volume of contA~ne~ water from the total volume of the wood material.
A6 described above, wood materials are ~ lly deformed when a pressure of 15 kg/cm2 i8 applied thereto. The materials are, hcwe~_~, deformed due to shock ari~ing from a pressure difference which iB caused by a cn~n application of pressure from no pressure to 15 kg/cm2. Accordingly, if the pressure is applied in steps to the wood material a6 it i8 in the present invention, the wood material is not easily deformed even when the final pressure applied thereto eYcee~
15 kg/cm2.
In the present invention, in each 6tage ~e~ e i6 applied for a predetermined time 80 that the internal portion of the wood material is sub~ected to the pressure of a , part$cular pressure-applying st_ge. Therefore, even if, for example, a pre6sure of 25 kg/cm2 i6 _pplied, the pre6sure increase during pre66ure appllc_tion i8 merely the relative pressure difference between the internal and extern_l portions of the wood materiAl. That is, the pres6ure which the wood material exper1ences i6 merely lO kg/cm2 (25 kg/cm2 minus the previou6 applied ~eD~ura of 15 kg/cm2), cau6ing no deformation.
Accordingly, according to the pre6ent invention the treating-liquid in~ecting 6tep carried out 6tepwise allows the aspirated pit-pairs and the like to be de~.oyed to those at the internal portion of the wood material, without deformlng the wood materlal ltself.
In each pressure stage, lt 18 preferable that for the first few pressure appllcation stages of up to _bout 15 kg/cm2 the material is malntA~ne~ at a part1c~Ar pressure ~or a relatively long period of time of lO minutes or more, while the length of time can be shortened thereafter.
Pressures in the initial pres~u~e applying/in~ecting step and the treating-liguid ~n~ecting step, the pressure difference for each stage, and the length of time the material is maintA~e~ at A cert_in pres6ure are naturally set at different values in accordance with the kind, type _nd dimensions Or the wood mater~al. For exa~ple, the pres6ure difference i6 made large when a large p~e~u~e is required to de~oy the torus 3, and the material is mainta~e~ at a certain pressure for a longer period of time when time i6 reguired to equalize the pressure to the inner portion of the wood material.
In the treatlng-llquld in~ecting 6tep, the treating liquid i6 in~ected into the material to be treated with a liquld pres6~e applying pump lS of dellvery constant type and _llowed to spread th~o~Jl,~ the materlal under a cert_in ~, pre66ure. At thi~ time, the g~se6 L~ -1ning in the tracheid 21 of the material and the g~es ~ n~ ng in wood cell6 _re first compres6ed to minimum volumes. Then, ba6ed on the Henry ~ 8 law, those gase6 finally dis601ve in the treating liguid. In the prior art p~oce66, ~ince the applied pre6sure is 6et to an insufricient level from the relation to destruction of the wood material, pool6 of gases are pro~l~ce~
in the treated wood. At the time the pressure applied externally is in h~ 1 Ance with the pressure in6ide the treated wood, there G~ 6 a condition in which the pools of gases function like air spring6. Accordingly, these air springs p~evenL in~ection Or the treating liquid, making it difficult for the treating liguid to penetrate into the core of the treated wood. In the present invention, however, the problem of des~Luo~ion of the material iB solved and the high-pressure o~e6s can be performed at the final applied pressure of 5 kg/cm2. The high ~Le~8u~e pLoca88 ~nAhl~q the ga6es in the treated wood to be dissolved in the treating liquid based on the-Henry's law, and hence the treating liquid can be in~ected into the core of the treated material.
on the other hand, after in~ecting the treating liguid by applying pres6ure a6 de6cribed above, the treated wood must bQ
released from the pLas~uLi~ed state. H~we~" if the rai6ed pressure i6 rlddenly removed, the ga6es dissolved in the treating liquid based on the Henry' 6 law may be abruptly eYrAnA~d~ cau6ing the wood material itsQlf to be de_L-oyed.
More 6pec~fically, since the volume change of liquid i6 much smaller than the volume change of gas with re6pect to pres6ure, the pre66ure in the ~e5D~LL vessel 12 would be 6~dA~n~y d~Gpped if the treating liquid i6 ~e~u~..ed at a time from the pressure ve66el 12 filled with the treating liquid to the treating-liquid reservoir 16. Co~.e~on~ngly, the gase6 dissolved-in the treating liquid inside the treated material A~

~- 2 1 1 3 6 6 1are so _bruptly ~YpAn~d a8 to de~troy the m_terial. For conifers cGr.L.ary to that the wood is thinned or deformed if 6u~nly sub~ect to the externally applied pre6sure of 15 kg/cm2 or h~gh~, the wood i~ des~oyed upon a sudden pre66ure ~.~ î v~l~ In this embodiment, the treating liquid inside the treated wood contains the gases dissolved therein under the pre6sure Or 45 kg/cm2. Accordingly, if the treated material i6 ~Ae~ly ~c~u~ed to the atmospheric pressure, it would be de6troyed from the inside by forces cGrLes~onA~ng to 45 kg/cm2. In thi6 embodiment, therefore, it i6 required to con~ol the eYpAn~on 6peed of the ga6es di6~01ved in the treating liquid for ~ra~t--~ing the wood material from being de~L.o~ed.
For that reason, the present invention particularly includes a pre6sure-removing 6tep (S7) and a pressure-removing tank 18 in the treating apparatus. The pressure-removing tank 18 is previously rilled with a ~o~inflammable gas which is supplied from, e.g., a gas pump or a nitrogen or carbon dioxide gas bomb and i8 pressurized to the same level as that in the pressure vessel 12. Then, the gas is Al ~hArged little by little from the pressure-removing tank 18 through a pressure-L~ -~ing valve 19 80 that the pre66ure in the pre66ure ves6el 12 i6 gra~ lly lowe~ad. At thi6 time, the p. ~ 6 F"re in the pre66u~a l_~oving tank 18 i6 lowe-ed at the same rate a6 that at which the pre66urQ in the pressure ve66el 12 i~ ed. Accordingly, the eYr~n~ion 6peed of the di6601ved ga6e6 in the treated wood can be con~.olled ~p~n~g on an op~n1ng degree of the pre6Du~e .emoving valve 19. With the con~.ol of the pres~ure reduction rate, it is po66ible to expel the ga6 which has a 6maller molec~lar 6tructure than the treating liquid out of the treated wood earlier than the treating liquid, and to leave the treating liquid 6ufficiently in the treated wood.

A' -The condltion of the wood mnter$al treated using the trent~ng-liquid in~ectlng method o~ the pre6ent --hoA~ -nt, and that treated using a conventional treating-liquid in~ecting method are 6hown in Fig. 6 for comparison. A water-soluble dye wa6 in~ectQd using the pre6ent method and a conventional method, and then each treated wood material wa6 cut for comparison (J~r~ne~e cedar and radiator pine heart wood h~ving a water content of 55S and mea6ur$ng 20 x 20 x 100 cm were used). As i6 apparent from Fig. 6, the wQod material treated by a convcr.~Qn~l method only permits a 6mall r L
of treating liquid to enter from the cut end face, and almo6t no treatinq-liquid is in~ected from the other face6. That i6, in 6pite of the in~ection from the cut end face, the portion near the 6urface 13 alone was deeply colored, and as regard6 the interior, only the ve66~l~ were colored within 5 cm or 60 from the 6urface, or with the color becom~ng thin gradually.
On the other hand, ~ccording to the ~e~ont method the treating liquid i6 in~ected from any direction, from the cros6-grain, 6traight-grain, and the like, and besides, tho~gh the surface wa6 a little deep, the light and shade of the color wa6 hardly 6een in the interior. That i6, according to the ~LP çnt method the ray pa,encl,~ma cell wall6 and the a6pirated pit-pair6 in the material are ~ ~,oyed for in~ecting the treating liquid, 60 that the treating liqu$d i6 con6i6tently in~ected not only into the materi~l~6 6urface but to it6 ce.,~al portion, thereby po6ing no problems when heart wood i8 used as the material to be treated.
Fig. 12 shows the condition6 of cells of the treated wood material before and after the in~ect~n of the treating liquid in the present invention. Fig6. 12~a) and 12(b) 6how the condition6 of wall plts before the in~ection, wherea6 Figs.
12(c) and 12(d) 6how the condition6 of wall pit6 after the in~ection. Fig6. 12(a) and 12(c) show the condition6 of cell6 ~.~

- 21 1~661 of sap wood, whereas Figs. 12(b) and 12(d) shoW the condltion6 of cells of heart wood. Wlth the in~e¢tion, the conditions are changed from Fig. 12(a) to Fig. 12(c), from Fig. 12(b) to Fig. 12(d). Note that Figs. 12(a) and 12(b) c~L.e~pond .e~e~ively to the ~tates of Figs. 9(a) and 9(b) when viewed from the outer side. A6 seen from Figs. 12(c) and 12(d), the wall pit~ are bro~n in all wood region up to the core, by uging the method of the present invention. It is thus shown that the treating liquid peneL,ates into the heart wood.
In this r ~o~ , the amount by which the treating liquid can be in~ected is calculated beforehand from the water content, the vacancy rate, the weight and the volume of wood.
Taking into accoun~ the errors due to impurities, 70 to 80S of the calculated in~ectable amount is set a8 the amount by which the treating liquid can be pract~c~l~y in~ected. Fig. 11 shows experimental results including data such as the specific weight before and after the treatment. In Fig. 11, (a) represents in~ection data for lo~go ~ole pine, (b) for red oak, and (c) for marble.
Here, the water content U can be ex~essed by:

U ' x 100 where GU - weight of wood, and G0 - volume of wood x total dry ~pec~ ric weight of wood The vacancy rate C can be ex~e6sed by:
ro l.S (true rpec~ic weight) where ro - total dry specific weiqht of wood, and 1.5 - true specific weight of wood The weight A of water cont~e~ in the wood can be ex~.e66ed by:

A c GU - (GV x x l.S) ~'A ~

21 13661 ~
Therefore, the in~ectable amount B c~n be determined below using the weiqht A of water that i6 converted into volume:
B - (GV x C) - A
where GV - volume Or wood In consideration of an effect of impurities su¢h as rosin and tylo6is, B x (70 to 80%) i6 set as the practical in~ectable amount.
The treating liquid can be in~ected until rea~-h~ng the practical in~ectable amount thus calculated. While confirming a reduction of the tre~ting liguid in the in~ected-r -u..L
calculating tank 17, the treating liquid i6 in~ected until reaching the practical in~ectable amount. At'thi6 time, if the in~ected amount does not reach the ~L ~ ' ~ amount, the pressure-applying time at the final applied pressure is exten~e~ 80 that the treating liquid i6 in~ected into the wood core.
To describe it in more detail with reference to Fig.
ll(a), since the calculated in~ectable amount i~ 52.5 1, the practical in~ectable amount is about 37 1. On the other hand, the actual injectable amount is 31 1. This value of 31 1 i8 within the range where it can be tho~ght that in~ection of the treating liquid has been completed 6ubstantially to 100%, ta~ng into acco~ .L different wood ~LvpcL~ies (heart wood or sap wood) and variations in individual wood material6.
Particularly, 6ince this embodiment employ6 heart wood for which in~ection of the treating liquid i6 hard, it i~
rea~onahle to think that the treating liquid ha6 been 6ufficiently in~ected into the wood core, al~ho~gh the actual in~ected amount i6 about 6 l le66 than the practical in~ectable amount. For comparison, in the ¢on~cn~Qnal 6imple pressing method, the treating liquid only les6 than 5 1 could be in~ected into lodge-pole pine under the same wood A~ - 27 -''~

. .
conditions even with a heating process applied. According to the present invention, the treatlng liquid can be in~ected in the amount 6 or more times as much as the conventional method at the normal temperature as described above.
A return of the treating liguid after the pressure removal in Fig. 1 i6 presumably ascribed to that some treating liquid is pushed out by the dissolved gases, and that the wood compressed under pressure increases its volume when returned to the atmospheric pressure.
Usable liquids to be in~ected include vegetable oil and mineral oil emulsified and made water-soluble by cationic surfactants to which are mixed antiseptics, insecticides, ant killer substances, and mold retarders. The treating liguids to be in~ected, which are cationic, combine ionically with the anionic wood material to prevent leakage from the wood material, making them suitable treating liquids.

Further, cation-base pharmaceuticals have a strong sterilization effect as well known, and di-decile di-methyl ammonium chloride (DDAC) as one kind of cation-base pharmaceuticals is used as a wood preservative over the world. It is also known that oil has an effect of preventing cracks or distortions of wood. By using oil and any of cation-base pharmaceuticals in a combined manner, it is possible not only to develop a preservation effect, but also prevent cracks or distortions as defects of wood, thereby enabling wood to be more effectively utilized. In addition, an oil component which has become water-soluble due to the combined use is advantageous in that its emulsified state is broken with drying of wood, allowing only moisture to evaporate, and the remained oil component develops a water repellent effect and also contributes to a preservation elfect. In this case, the remained oil component is less dissolved in water again, beca~se it is cationic and ha6 been once separated from the emulsified state. Furthermore, a . ~ .

21 1~66 1 treating liquid prepared by emulsifying oil in a cation-base surfactant has a small grain slze and hen¢e can be easily in~ected into wood. Compared to water-601uble glycol6 used a6 treating liquids, the6e treating liquid6 ~ ever.~ leakages from G~L~ ing and have better dimen6ional 6tability and the like over a longer period of t$me. In addition, emul6ifying them by non-ionic and A~1Qn~c surractants and A~dtng ant~re~Lics thereto allow the same effects to be obtA~ned. Further, 6ince in the pre6ent method the treating liquid can be in~ected to the central portion of the wood material, a treated material having a h1gh~r flame resistance than the con~el.~ional treated materials can be obt~A~ne~ by the in~ection of flame rQtarders.
A ~e_~n~ embodiment of the treating-liquid in~ecting method related to the present invention will be herel~nd~r described. The 8eCQ~ : ho~ ~ent is a method for in~ecting the treating liquid into broadleaf trees (red oak). Fig. 2 illu6trates graphs showing the reduction and application of pre6sure during the treatment.
Compared with the aforement1one~ ¢onifers, broA~lenf trees IlF~lal~y have many thick ve~Fel~ which pass water.
Therefore, it may be seen that these veFrel~ can be used to ea6ily in~ect the treating Iiquid. Pcwe~er, these vefireJ~
actually contain a large amount of impuritie6 such as tylo6e.
Accordingly, applying pre66ure all at once cal~r~F the impuritie~ to get clogged in the veFFel~, pLe~an~ing in~ection of the treating liquid. For thi6 reason, a6 regard6 the pre6ent invention, in the initial pres6u.e applying/in~ecting step, to make the treating liguid go through the ve66el~ and conrequently to transmit equal pres6ure of the liquid are followed by to in~ect the treating liquid to the central portion of the material, by applying a relatively low pre6sure which doe6 not cause the impuritie6 to get clogged in the Ve68eJ 6 over a long period of time. Thus here too, the A~

211366 1 ~i initial pres6ure-applyinq/in~ecting 6tep of the pre6ent invention i6 of different ~ignif1c~e from a mere fir6t step of the stepwise p~e~u~e application.
The present method 6et6 the pre66ure-reducing time at more than 30 minute~ at lea6t, preferably 60 minutes which i8 longer than that set for the conifers as 6hown ln Fig. 2, in view of the fact that the bro~le~ trees contain more elements in their vesEel~ compared to the conifers, which makes it neces~ry to minimize the influence of the gas in the ve~eJ F Oc~U~ L ing during pre~ure application by removing as much gas in the ves6el as possible (Sl).
Even in the following pres~Le applying step, a relatively low pressure of about 0 to 10 kg/cm2 is applied, 80 that the clogging ln the v~6~el~ does not occur. The pressure-applying time is set at 30 minutes, which is longer than i~ is for the conifers (refer to S2). In thi6 ~-ho~ , the treatment i6 carried out under o to 5 kg/cm2 in the same manner as the above described case for conifer6.
Thi6 is, in addition to the foregoing re~o~, because tracheids are more apt to be clogged in the case of broadleaf trees. Accordingly, it i6 ~ e~Lant in the case of broadleaf trees to perform this step under low pLa~uLe for a long time.
Accordingly, the treating liguid being made through the vesFels in advance, the ve~Fel~ can be set at a certain ple~ULe, without being hampered by ~_~Eol clogging. After a low pressure is applied for a long period o~ time, the pressure is applied in step6 at 6 to 15 kg/cm2 rOr 10 to 20 minutes, 16 to 30 kg/cm2 for 20 to 30 minutes, 31 to 45 kg/cm2 for 30 minutes and 80 on (S3-S5). Beside6, concel..ing the final pre6sure ~pplication, a6 mentioned above, it doe6 not matter whether pre66ure i6 applied until 50 kg/cm2 or at lower values than 45 kg/cm2 according to the kind of the wood material. In thi6 ca6e, the pre6sure on the broadleaf tree6 ~A ~' - 211366 1 .
can be increa6ed in a fewer 1- h~r of steps than for the conifers, 6ince they have larger number of ve6sel element6.
In the ca6e of broadleaf trees therefore, the treatment i6 generally ~r6~,L6sed like the following; a6 indicated by a dot line in Fig. 2, the time during which the low pres6ure is applied i6 long and, thereAfter, the ~s~ re is relatively quickly raised. Similarly, Alth~lgh the amount of treating liquid in~ected is moderately increAsed at the beglnn~ng, its gradient is quickly increased with a rise of the pre6sure. By oGI.LLast, in the case of conifer6, the pressure and the amount of treating liquid in~ected are genc~ally increased at a substantially uniform gradient, a6 ~n~cAted by a dot line in Fig. 1. After the treating liquid has been in~ected, the pres6ure is gr~ Ally ~. -ved using the pressure-removing valve 19 a6 de6cribed above (S6).
Obta 1 ne~ was the sa~e re6ult a6 those of the conifer6 that the treating liquid wa6 in~ected to the cen~ral portion of the treated material. Fig. ll(b) 6hows the6e data.
Furthermore,- in the case of broadleaf trees as well as conifer6, the pre~sure, the pressure difference, and the length of time the material i6 maintA~ne~ at a certain pres6ure can be set at different values for each step in _ccordance with the kind, type and ~ ion6 of the wood material.
Fig. 3 illu6tr_te6 gr_ph6 6howing the reduction and application of pres6ure during material treatment in the third embodiment of the treating-liquid in~ecting method related to - the pre~ent invention. The present embodi~ent i6 a method for in~ecting the treating liquid into ~or~us inorganic materials such a6 6tone material. In the pre6ent method, the time for reducing the pre6sure and the time for applying low pres6ure are made long. After the pres6ure is red~ce~ and low pre66ure i6 ~pplied, the pres6ure i6 increa6ed at once to a high ~ ,,, 2 1 ~ ~ 6 6 1 pres6ure, which allows in~ection of the treating liquid to the internal portion of the 6tone material.
Porous inorganic materials 6uch a6 marble contain a large quantity of ga6 in the$r interior due to their structure.
Accordingly, in the pre6ent method 6ufficient pre6sure-red~c~ng time i6 taken 80 that the gas in the interior can be sufficiently removed (81). In this case, it is desirable that the pressure-reducing time i6 longer than it i8 for the aforementioned broadleaf trees, tnerefore about 120 minutes.
Stone mater1al6 al60 contain a large A - L of fine impurities or ~ine pOwaer in t~eir interior. Accordingly, a6 an in$tial pre6~u~e applying/in~ecting 6tep, in order to prevent clogging by these entitie6 from oc~uL~ing, a relatively low pressure of about 5 kg/cm2 is applied for a longer period of time than for the wood material, for example for about 60 minutes (S2). Thi6 allows the material'6 interior to be at a certain pressure as is the case for the broadle_f tree6. After low pre6sure i6 applied for a long period of time, the treating-liquid in~ecting 6tep is carried out. In the pre6ent emhoA~ ?nt, ~nlike in the c_se of the wood material, a high pressure of 45 kg/cm2 i6 applied at once, becA-~e the 6tone material i8 not ea6ily deformed by pres6ure application (S3).
On the other hand, after in~ecting the treating liquid under high ~le6~u~e, the pres~uLe ~moving valve 19 i6 used to gradually remove the pressure a6 de6cribed above (S4).
Accordingly, according to the methods of the pre6ent invention, the treating liquid i6 in~ected to the ce~
portion of the material. A piece of 70 x 30 x 3 cm-marble (made in Italy) used a6 6tone material was in~ected with a water-601uble dye and then cut. It wa6 found that the marble wa6 uniformly dyed to it6 central portion, thereby verifying that the in~ected treating liquid doe6 reach the material'6 i ~

central portion. It goes without saying that in this case too, conditions of treatment are changeable according to the type of the material.
In the present method, using, for example, a Toa Kagaku's "Alone Water Shut" (trade name) whose major component is silane monomer further increases the treated stone material's resistance to acid rain. That is, the silane monomer in the base material chemically combines with the silanol and forms a layer highly effective in preventing water absorption, thereby protecting the stone material from damage caused by acid rain and the like. In addition, since the hair net pits in the stone material, particularly the marble, are not embedded, the stone material can be treated by taking advantage of its characteristics, without deteriorating the respiratory action of the marble.
Although embodiments of the invention have been described above, it is not limited thereto and it will be apparent to those skilled in the art that numerous modifications form part of the present invention insofar as they do not depart from the spirit, nature and scope of the claimed and described invention.

A '~'

Claims

1. A method of destroying ray parenchyma cell walls and aspirated pit-pairs of a conifer wood material, and injecting a treating liquid into a conifer wood material comprising the steps of:
a) an initial pressure application step of immersing said conifer wood material at ambient temperature in a treating liquid under an initial liquid pressure in the range of 1 to 10 kg/cm2 and maintaining said liquid pressure for at least 10 minutes to inject said treating liquid into tracheid of said conifer wood material;
b) a treating-liquid injecting step of increasing said liquid pressure on said conifer wood material with injected treating liquid at ambient temperature from said initial liquid pressure up to a final applied liquid pressure having a maximum value of 50 kg/cm2 in a stepwise manner, comprising a plurality of pressure increases of 5 to 10 kg/cm2 each, each pressure increase being followed by maintaining an increased pressure for at least 10 minutes to further inject said treating liquid under pressure into said conifer wood material while dissolving any gases in said conifer wood material in said treating liquid;
c) a pressure-removing step of reducing the liquid pressure on said conifer wood material from said final applied pressure to atmospheric pressure over a period of at least 20 minutes to prevent said conifer wood material from being broken due to abrupt expansion of any gases dissolved in said treating liquid which is injected into said conifer wood material; and d) said initial pressure application step and said treating-liquid injecting step being carried out using a constant volume pressure-applying pump resulting in pressurization under dynamic pressure, said pressurization being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

2. The method according to claim 1, further comprising, before said initial pressure application step, a pressure-reducing step of reducing gas pressure on said conifer wood material to less than atmospheric pressure, and maintaining a reduced gas pressure for at least 20 minutes to purge gases out of said conifer wood material.

3. A method of destroying ray parenchyma cell walls and aspirated pit-pairs of broadleaf wood, and injecting treating liquid into broadleaf wood comprising the steps of:
a) a pressure-reducing step of exposing broadleaf wood to a gas pressure no greater than atmospheric pressure, and maintaining said gas pressure for at least 30 minutes to purge gases out of said broadleaf wood;

b) an initial pressure application step of immersing said broadleaf wood in a treating liquid at ambient temperature under a liquid pressure in the range of 1 to 10 kg/cm2, and maintaining said liquid pressure for at least 20 minutes to inject said treating liquid into tracheid of said broadleaf wood;
c) a treating-liquid injecting step of increasing said liquid pressure of said broadleaf wood with injected treating liquid at ambient temperature up to a final applied liquid pressure having a maximum value of 50 kg/cm2 in a stepwise manner, comprising a plurality of pressure increases of 5 to 20 kg/cm2 each, each said pressure increase being followed by maintaining increased pressure for at least 10 minutes to further inject said treating liquid under pressure into said broadleaf wood while dissolving any gases remaining in said broadleaf wood in said treating liquid;
d) a pressure-removing step of reducing said liquid pressure on said broadleaf wood from said final applied pressure to atmospheric pressure over a period of at least 20 minutes to prevent said broadleaf wood from being broken due to abrupt expansion of any gases dissolved in said treating liquid which is injected into said broadleaf wood;
and e) said initial pressure application step and said treating-liquid injecting step being carried out using a constant volume pressure-applying pump resulting in pressurization under dynamic pressure, said pressurization being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

4. A method of injecting treating liquid into a stone material, comprising the steps of:
a) a pressure-reducing step of exposing the stone material to a gas pressure no greater than atmospheric pressure, and maintaining said gas pressure for at least 60 minutes to purge any gases out of said stone material;
b) an initial pressure application step of immersing said stone material at ambient temperature in a treating liquid under a liquid pressure in the range of 1 to 10 kg/cm2, and maintaining said liquid pressure for at least 60 minutes to inject said treating liquid into cracks inside said stone material;
c) a treating-liquid injecting step of increasing said liquid material of said stone material at ambient temperature up to a final applied liquid pressure having a maximum value of 50 kg/cm2 in a single step, and maintaining said final applied pressure for at least 30 minutes to inject said treating liquid under pressure into said stone material while dissolving any gases remaining in said stone material in said treating liquid;
d) a pressure-removing step of reducing said liquid pressure on said stone material from said final applied pressure to atmospheric pressure over a period of at least 20 minutes to prevent said stone material from being broken due to abrupt expansion of any gases dissolved in said treating liquid which is injected into said stone material;
and e) said initial pressure application step and said treating-liquid injecting step being carried out using a constant volume pressure-applying pump resulting in pressurization under dynamic pressure, said pressurization being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

5. The method according to any one of claims 1 through 3, wherein said treating liquid is a cation-base treating liquid prepared by emulsifying a plant oil or mineral oil with a cationic surfactant.

6. The method according to claim 4, wherein said treating liquid comprises a silane monomer.

7. An apparatus for injecting treating liquid into wood materials and stone materials, comprising:
a) a pressure vessel for accommodating a material to be treated in a sealed state, a depressurizer means for reducing gas pressure in said pressure vessel, a constant volume liquid delivery means for pressurizing said pressure vessel to a predetermined liquid pressure under dynamic pressure, and a pressure-removing means connected to said pressure vessel and comprising container means, means for pressuring said container means with a gas at said predetermined liquid pressure, and means for releasing pressurized gas in said container means to the atmosphere to thereby reduce said liquid pressure in said pressure vessel;
b) said constant volume liquid delivery means pressurizing to a liquid pressure in the range of 1 to 10 kg/cm2, maintaining said liquid pressure for at least 10 minutes and increasing said liquid pressure up to a final applied liquid pressure having a maximum value of 50 kg/cm2 in a stepwise manner for wood material or in a single step for stone material, said stepwise manner comprising a plurality of pressure increases of 5 to 20 kg/cm2, each said pressure increase being followed by maintaining increased pressure for at least 10 minutes to further inject said treating liquid;
c) said final applied liquid pressure being reduced to not greater than atmospheric pressure over a period of at least 20 minutes; and d) said pressurizing by said constant volume liquid delivery means being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

8. The apparatus according to claim 7, wherein said container means comprises a tank connected to said pressure vessel and said means for releasing comprises a valve connected to said tank and adapted to be opened and closed to reduce said liquid pressure in said pressure vessel.

9. A method of injecting treating liquid into wood materials and stone materials by steps, comprising:
a) immersing a wood or stone material in a treating liquid in a treating-liquid injecting apparatus which comprises a pressure vessel for accommodating a material to be treated in a sealed state, a depressurizer means for reducing gas pressure in said pressure vessel, a constant volume liquid delivery means for pressurizing said pressure vessel to a predetermined liquid pressure under dynamic pressure, and a pressure-removing means connected to said pressure vessel and comprising container means, means for pressurizing said container means with a gas at said predetermined liquid pressure, and means for releasing said pressurized gas in the container means to the atmosphere to thereby reduce said liquid pressure in the pressure vessel, increasing said liquid pressure of the immersed wood or stone material, and subsequently reducing said liquid pressure, further comprising the step of controlling said pressure-removing means so as to reduce said liquid pressure in said pressure vessel to atmospheric pressure over a period of at least 20 minutes, thereby suppressing expansion speed of any gases dissolved in said treating liquid and discharging said gas from immersed wood or stone material prior to said treating liquid, said stepwise manner comprising a plurality of pressure increases of 5 to 20 kg/cm2, each said pressure increase being followed by maintaining increased pressure for at least 10 minutes to further inject said treating liquid;
b) said constant volume liquid delivery means pressurizing to a liquid pressure in the range of 1 to 10 kg/cm2, maintaining said liquid pressure for at least 10 minutes and increasing said liquid pressure up to a final applied liquid pressure having a maximum value of 50 kg/cm2 in a stepwise manner for wood material or in a single step for stone material; and c) said pressurizing by said constant volume liquid delivery means being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

10. The method according to claim 9, wherein said container means comprises a tank connected to said pressure vessel, and said means for releasing comprises a valve connected to said tank and adapted to be opened and closed to reduce said liquid pressure in said pressure vessel, further comprising the step of controlling said valve so that said pressure in said pressure vessel is reduced to atmospheric pressure over a period of at least 20 minutes.

11. The method according to any one of claims 1 through 4, wherein said final applied liquid pressure has a value of 30 to 50 kg/cm 2.

12. An apparatus for injecting treating liquid into wood materials and stone materials, comprising:
a) a pressure vessel for accommodating a material to be treated in a sealed state;
b) a depressurizer means for reducing gas pressure in said pressure vessel;
c) a constant volume liquid delivery means for delivering a treating liquid to said pressure vessel and pressurizing said pressure vessel to a predetermined liquid pressure under dynamic pressure;
d) a pressure-removing means for said pressure vessel and comprising container means having therein a gas pressurized to said predetermined liquid pressure, fluid connection means between said container means and said pressure vessel and valve means for selectively venting said container means to atmosphere, whereby release of said pressurized gas to the atmosphere reduces said pressure in said pressure vessel;
e) said constant volume liquid delivery means pressurizing to a liquid pressure in the range of 1 to 10 kg/cm 2, maintaining said liquid pressure for at least 10 minutes and increasing said liquid pressure up to a final applied liquid pressure having a maximum value of 50 kg/cm 2 in a stepwise manner for wood material or in a single step for stone material, said stepwise manner comprising a plurality of pressure increases of 5 to 20 kg/cm 2, each said pressure increase being followed by maintaining increased pressure for at least 10 minutes to further inject said treating liquid;
f) said final applied liquid pressure being reduced to not greater than atmospheric pressure over a period of at least 20 minutes; and g) said pressurizing by said constant volume liquid delivery means being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.

13. The apparatus according to claim 12, additionally comprising means for containing a treating fluid in fluid connection with said liquid delivery means.

14. The apparatus according to claim 13, additionally comprising a liquid measuring reservoir disposed between said treating fluid containing means and said constant volume liquid delivery means, and a means for throttling said liquid delivery means to maintain a constant pressure in said pressure vessel when said predetermined pressure is attained in said pressure vessel.

15. A method for injecting treating liquid into wood or stone material, comprising the steps of:
a) placing said wood or stone material in a pressure vessel of an apparatus comprising a pressure vessel for accommodating a material to be treated in a sealed state; a depressurizer means for reducing gas pressure in said pressure vessel; a constant volume liquid delivery means for delivering a treating liquid to said pressure vessel and pressurizing said pressure vessel to a predetermined liquid pressure under dynamic pressure; and a pressure-removing means for said pressure vessel and comprising container means having therein a gas pressurized to said predetermined liquid pressure, fluid connection means between said container means and said pressure vessel and valve means for selectively venting said container means to atmosphere, wherein release of said pressurized gas to the atmosphere reduces the liquid pressure in said pressure vessel;
b) delivering said treating liquid to the pressure vessel until a predetermined final pressure is attained;
c) venting said pressurized gas in said container means to atmosphere, to thereby reduce said liquid pressure in said pressure vessel;
d) said constant volume liquid delivery means pressurizing to a liquid pressure in the range of 1 to 10 kg/cm 2, maintaining said liquid pressure for at least 10 minutes and increasing said liquid pressure up to a final applied liquid pressure having a maximum value of 50 kg/cm 2 in a stepwise manner for wood material or in a single step for stone material, said stepwise manner comprising a plurality of pressure increases of 5 to 20 kg/cm 2, each said pressure increase being followed by maintaining increased pressure for at least 10 minutes to further inject said treating liquid;
e) said final applied liquid pressure being reduced to not greater than atmospheric pressure over a period of at least 20 minutes; and f) said pressurizing by said constant volume liquid delivery means being raised gradually with repeated increases and decreases of said pressure due to destruction of said ray parenchyma cell walls until reaching a setting pressure, wherein delivery of said treating liquid is throttled so as to maintain said setting pressure.