DEVICE FOR THE HEAT SHRINKING OF THERMOPLASTIC SLEEVES ON GAS CYLINDERS

Abstract: The device for the heat shrinking of sleeves on Gas Cylinders described herein is a piece of equipment that works by means of compressed air and steam. Basically it comprises two opposite twin units, each made up of a hemisphere (17, 8) driven by a piston (21) which pushes it against the other unit. Working simultaneously, at the point of contact the units grip and surround the cylinder, placed in the steam area, forming a chamber into which steam is injected at a given pressure, thus heat shrinking the sleeve placed in the cylinder beforehand.

Description: DESCRIPTION DEVICE FOR THE HEAT SHRINKING OF THERMOPLASTIC SLEEVES ON GAS CYLINDERS This invention relates to a Sleeves Steam Wrapper for Gas Cylinders . The sleeves bear information about the nature of the product contained in the cylinder, as well as information about safety, handling and first aid in case of accidents. Gas cylinders sold in Portugal are fitted with a detachable disc containing the said informatioa However, these discs sometimes fall off during -transport and some cylinders are therefore sold not bearing the information required by law. This invention solves the problem in an innovative way. It simultaneously ensures permanent provision of information, greater durability, 100% recycling and energy saving, which all contribute to greater economy and improved environmental protection STATE OF THE ART After conducting a market survey we concluded that the most efficient and long lasting method of attaching the information is the use of retractable polyurethane sleeves that almost totally cover the cylinder. A number of methods exist for fitting these sleeves and they are used in various industries, for example for labelling soft drinks and for protecting products. But they have never been used on gas cylinders. These systems employ heating by hot air or steam in tunnels to retract the sleeves. A preliminary search showed the most important patent to be WO 9011223 of Bressendorf Ole for a film retracting method using heat and a tunnel. It also uncovered patent US 56116425 relating to a pasteurisation method and device for a continuous line of products. As well as being rather expensive, since they use electrical energy and/or steam continuously, these methods also result in a major loss of energy, which invariably contributes to increased levels of pollution and heating of the planet. On the other hand, experience shows that applying this continuous flow steam tunnel technique directly is ill advised for gas cylinders due to the physical and chemical behaviour of the various materials. And not just the product in the cylinders but also the materials making up the actual cylinders and fittings, in particular, the steel body and the brass, along with the plastic, rubber and soft steel making up the valve. This mix of materials, with such a different coefficients of expansion, constitutes a safety risk not only during cylinder filling but in terms of component ageing, i.e., loss of elasticity due to large temperature changes from 15/20C to 100/120°C and the length of exposure inside the steam tunnel, reckoned at 21 seconds for retracting each sleeve. For some of the components, such as the valve O-rings, the temperatures reached are very close to the manufacturer's recommended yield point. This is a strong argument for not using a continuous flow steam tunneL The pressure of the gas in the cylinders, in a liquid state at pressures of between 2 bars for butane and 5 bars for propane, rises due to the sudden increase in temperature and consequently represents a safety risk at the filling station. This invention, called a STEAM DRAGON, solves these problems, since it uses only non- polluting energy sources that are not a danger in highly explosive working areas: - compressed air - steam. And the system works on a cylinder-by-cylinder basis that dramatically reduces the length of time each cylinder is exposed to the steam from 21 seconds to 0J seconds. This accounts for an energy saving of about 90% or more, and avoids injecting the steam directly into the cylinder's more sensitive parts, in particular the valve. EQUIPMENT The Steam Dragon is basically comprised of two opposite twin units or subsystems (Fig.l), working simultaneously. Each unit is made up of a hemisphere or steam chamber (7) and a perforated metal plate (8) on the inside, acting as a steam outlet. The units join together when a cylinder passes, surrounding it almost completely and forming a steam or pasteurising chamber while leaving the valve outside. Each twin unit is fitted with a steam line consisting of an insulated cylinder and pipe with a hose to carry the steam to the consumption area, where it enters the equipment. As the steam is produced discontinuously a condensation trap is incorporated in the steam line (Fig. 11). Each unit consists of: - base plate(l) - left guard (2) of hemisphere with slit for fitting of steam line - right guard (3) of hemisphere - chamber support (4) - steam chamber upper support (5) - steam chamber lower support (6) - steam chamber back end plate (7) - steam chamber perforated plate (8) - steam hose connector (9) - piston (21) - guiding shaft (15) Each unit is fitted with a guard (Fig. 8 & 9) that completely covers it and contains a slit at the side for the steam line. The equipment also consists of an infrastructure made up of a line for conveying the cylinders through the steam area, that includes a compressed air admission sensor to control, upstream, the flow of cylinders in the sleeve attaching area and, downstream, the- admission into the steam area. The conveying line has a brake (Fig.10), fitted with a pneumatic piston (22), to hold the cylinder when another is already in the steam area. The attached figures show: FIG. 1 - Perspective of a twin units set FIG. 2 - Plan of operating installation - during steaming phase FIG. 3 - Elevation of operating installation - during steaming phase FIG. 4 - Plan of installation on standby FIG. 5 - Elevation of installation on standby FIG. 6 - Exploded diagram of a twin unit FIG. 7 - Steam chamber hemisphere (side and front elevation, plan) FIG. 8 - Plan of equipment guard cover FIG. 9 - Elevation of equipment guard cover FIG. 10 - Perspective of brake at beginning of cycle FIG. 11 - Assembly diagram for steam line draining system FIG. 12 - Diagram of steam circuit OPERATION As mentioned above, the cylinders are carried to the steam area by a conveyor and its various compressed air sensors control the flow of cylinders, first in the sleeve attaching area and then at the steam area entrance. These sensors are part of an automated system and are linked to the steam system. A timer controls the injection of steam into the chamber. When information is received from a sensor that cylinder 1 has entered the steam area, a brake piston is operated by compressed air at the beginning of the cycle (Fig. 10), which restrains cylinder 2 on the conveyor so that another cylinder cannot force its way into the hemispheres. As the rod (45) driving the brake pushes back the stopper (46) and allows the cylinder to pass, two pistons (21) are automatically actuated which push the hemispheres against the cylinder with the sleeve already attached, totally surrounding it and gripping it. Steam, which meanwhile has been carried by the insulated pipe and the steam hose, is injected into the chamber formed by the junction of the two hemispheres through the holes in the perforated plate (8), causing it to stick to the outer walls of the cylinder. This process takes only 7/10 second. At the end of that time the pistons (21) pull the hemispheres (7) back, releasing cylinder 1. At the same time the brake (FIG. 11), which was restraining the cylinder, is removed, releasing the cylinder and restarting the cycle. LEGEND

Claims: CLAIMS Sleeves Steam Wrapper for Gas Cylinders, working off compressed air and steam, characterized to be employed on a bottle-by-bottle basis using a discontinuous injection of steam and without hitting the valve area, the equipment comprising basically two opposite twin units or subsystems (Fig.l), which work simultaneously; each unit is made up of a back end plate (7) and a perforated metal plate (8) on the inside, acting as a water vapour outlet; both hemispheres are driven by a piston (21), which pushes them, against each other up to the point of contact where they form a pasteurising chamber that grips and surrounds the cylinder that has previously been placed between them in the steam area by an automatically controlled conveyor, having each unit or subsystem it's own steam circuit (Fig. 12) and an external guard (Fig. 8 & 9). Sleeves Steam Wrapper for Gas Cylinders such as claimed in 1 , characterized by consisting of two units, which are the sub-divisions of the actual system and are comprised of: - base plate(l) - left guard (2) of hemisphere with slit for fitting of steam sleeve - right guard (3) of hemisphere - hemisphere fixing and support system (4,5 & 6) - hemisphere back end plate (7) - hemisphere perforated plate (8) - steam pipe connection (9) - piston (21) - steam line Sleeves Steam Wrapper for Gas Cylinders such as claimed in 1 and 2 , in which the steam line consists of an insulated cylinder and tubing with a hose to carry the steam to the consumption zone, where it enters the equipment through the connector (9) at a pressure of between 0.5 and 2.0 bats; a liquid draining system (Fig. 11) is incorporated in the steam line. Sleeves Steam Wrapper for Gas Cylinders such as claimed in 1, that includes guards that protect and cover each of the twin units; the guards consist of a rectangular box (Fig. 8 & 9), extending to the rear in a frustum shaped section, finished off with a lid; a slit is cut into the side of the box for the steam pipe. Sleeves Steam Wrapper for Gas Cylinders such as claimed in 1, in which the equipment consists of an infrastructure made up of a line for conveying the bottles to the steam area, that includes a compressed air admission sensor to control, upstream, the flow of cylinders in the sleeve placing area and, downstream, the admission into the pasteurisation area; the conveying line has a pneumatic brake (Fig.10), fitted with a piston (22), rod (45) and stopper (46) to hold the cylinder and prevent another cylinder forcing entry into the steam area.

Inventors: DOS SANTOS PIRES ANICETO, MARTINS NEVES DOS SANTOS JOAO, DOS SANTOS PIRES, ANICETO, MARTINS NEVES DOS SANTOS, JOAO, LUIS
Applicants: BP PORTUGUESA S A, DOS SANTOS PIRES ANICETO, MARTINS NEVES DOS SANTOS JOAO, BP PORTUGUESA, S.A., DOS SANTOS PIRES, ANICETO, MARTINS NEVES DOS SANTOS, JOAO, LUIS
Application year: 2001
Main classification: B65C3
IPC codes: B29C35, B29C61, B29C63, B65C3, B65C9, F17C13