Patent GB-1416428-A (GB)
Title: Apparatus and method for treating materials
IPC: B27K3/02
Filed: 1972-02-07
Abstract: 1416428 Treating materials e.g. timber CUPRINOL Ltd 7 Feb 1973 [7 Feb 1972] 5676/72 Heading D1P An apparatus for treating materials comprises a treatment chamber 1 having a lower part 3 for containing a treatment fluid, and an upper part, means 2 for supporting the material to be treated, means such as 6 for moving the supporting means between the upper and lower parts of the chamber, means for altering the pressure within the chamber relative to ambient pressure, and an arrangement o'f tanks for measuring the amount of fluid taken up during a treatment. The supporting means preferably comprise a cage 2 raisable and lowerable between guide bars 17 by jacks such as 6 which may operate directly or indirectly from above or below and with or without counterweights. In its upper position the cage 2 is in alignment with a post or door 5 which may be at ground level and through which the material to be treated, e.g. timiber, may be loaded into the cage. The cage may be fitted with rails to receive trolleys and a further door may be provided at the opposite end of the chamber. The apparatus is constructed to withstand vacuum and if necessary excess pressure which may be applied along a line 7 by a suitable vacuum, pressure or dual purpose pump (not shown). Thus the apparatus is suitable for treating timber by a simple immersion treatment, an immersion treatment with vacuum recovery, a pre-immersion vacuum treatment or a double vacuum treatment, as well as by a pressure process such as that of Lowry, Rueping or Bethell. For measuring the quantity of treating fluid taken up by the process, there is provided an amplifying vessel 8 of small horizontal cross section compared with the chamber and connected in line between the chamber and a holding tank containing a reserve supply of fluid, there being provided means for transferring to the amplifying vessel liquid above a predetermined level in the chamber. A pipe 9, optionally containing a shut-off valve, connects the vessel to the chamber and opens into the chamber ,precisely at a level (L1) corresponding to the initial level of fluid in the chamber. The vessel is provided with level measuring devices e.g. float gauges or level sensors, or a sight glass. In operation, the vessel is charged with a quantity of fluid from the holding tank, the quantity being in excess of the expected take-up, and the level (A) in the vessel measured. The charge is then transferred to the chamber, the level in the vessel falling to a point (c) and the level in the chamber rising above (L1). After the treatment is complete, the fluid in the chamber above the level (L1) is transferred back to the vessel and occupies a new level B intermediate A and C, the difference in levels A and B corresponding to the intake of fluid during the treatment. The vessel 8 may be separate from or constructed integrally with the chamber 1, as may the holding tank. In the latter case vertical partitions may be provided in the chamber dividing into a centre treatment section and two lateral segmentshaped holding tanks, (15), (16) Fig. 8 (not shown). Instead of providing an amplifying vessel, a sight glass or level measuring devices may be provided in the chamber itself, or load cells may be attached to the cage. The apparatus is provided with a series of vacuum or if desired pressure release valves positioned on the chamber or remotely therefrom but connected thereto by a pipe having interposed therein a simple on/off isolating valve. These release valves may be adjusted to be operated at a particular vacuum or pressure level in the chamber according to process requirements. The valves may be controlled for an automatic process in dependence upon a series of electronic relays, time clocks, position and pressure switches, or alternatively the valves may be pneumatically or even manually controlled. The response time of the valves and the power of the vacuum pump may be adjusted to give an oscillating pressure change in the chamber. Steam or electrical heating means may be provided to enable elevated temperatures to be used. The treating chamber may be of square cross section. In the treatment of timber, the wood is loaded into the cage in its upper position, the cage lowered so as to immerse both timber and cage in the treating fluid, and, after a suitable treatment time, the cage raised to its upper position and the wood removed from the chamber. The pressure in the chamber may be reduced by drawing a vacuum on line 7 whilst holding the timber in its upper position, and allowed to rise to atmospheric after immersion of the timber, to aid impregnation. Vacuum may be applied again after raising the cage, to assist removal of treating fluid from the wood. The timber treated may be in the form of fence or transmission posts, window frames or door parts. Other materials which may be treated include plywood, blockboard, laminates, chipboard, hardboard, insulation board, textiles, rope, yarn or cordage. The treating fluids may comprise wood preservatives such as copper naphthenate, pentachlorophenol, tributyl tin oxide, lindane or dieldrin, in an organic solvent such as white spirit, petroleum distillate, coal tar naphtha or creosote or water-borne materials such as copper-chrome-arsenic salts.