Technical Field

The present invention relates to drycleaning equipment. More particularly, the present invention relates to drycleaning machines which have solvent vapor removal systems that reduce environmental emissions and operator exposure.

Background Art

In addition to being suspected carcinogens, drycleaning solvents such as perchloroethylene are known to can cause liver and kidney damage. In addition, drycleaning solvents such as perchloroethylene are hazardous air pollutants (HAP) which contribute to ozone depletion and global warming.

Because of the dangers associated with drycleaning solvents, the most desirable drycleaning equipment is that which has the ability to reduce occupational exposure and environmental emissions.

In recent years, drycleaning equipment has been designed to reduce environmental emissions. Most of the design changes have been directed at leak resistant, sealed systems with vapor recovery provisions. In general, there are two types of cleaning solvent vapor recovery systems used in modern drycleaning equipment:

those using a refrigerated condenser, and those which use a carbon adsorber. A refrigerated condenser is the primary device used to recover perchloroethylene vapors during the dry cycle. An efficient refrigerated condenser alone will generally reduce the perchloroethylene concentration in the cleaning chamber to between 1500 and 2000 ppm. This concentration level of residuals in the cleaning chamber provides a significant source of emission pollution and hazardous exposure to workers during continuous loading and unloading operations.

In order to reduce the concentration of residual cleaning solvents at the end of the dry cycle a number of control systems have been proposed. However, systems proposed here-to-date lack isolation and effective removal of solvent vapors.

Disclosure of the Invention

It is accordingly one object of the present invention to provide a means for reducing occupational exposure to cleaning solvents during a drycleaning process.

Another object of the present invention is to provide a means for reducing the emission of cleaning solvents during a drycleaning process. A further object of the present invention is to provide a drycleaning machine which includes means to isolate and remove residual solvent vapors before the machine chamber is opened.

A further object of the present invention is to provide a drycleaning machine which includes a ventilation system which effectively contains and removes residual solvent vapors.

A still further object of the present invention is to provide a method for reducing the emission of cleaning solvents during a drycleaning process.

A still further object of the present invention is to provide a method for isolating and removing residual solvent vapors from a drycleaning machine after the drying cycle is complete.

According to these and further objects of the present invention which will become apparent as the description thereof proceeds, the present invention provides for a drycleaning apparatus which includes: a chamber for receiving and containing cleaning solvents, a cage for receiving articles to be cleaned positioned in said chamber, at least one cleaning solvent supply line, at least one cleaning solvent removal line, actuator valves positioned between said chamber and each of said at least one cleaning solvent supply line and said at least one cleaning solvent removal line for isolating said chamber from said at least one cleaning solvent supply line and said at least one cleaning solvent removal line.

The present invention further provides a method of controlling, containing and removing residual cleaning solvent vapors from a drycleaning machine after a drying cycle which involves the following sequence of method steps: activating actuator valves which isolate a drycleaning machine chamber from lines which supply and remove cleaning fluid to and from said machine chamber; and drawing an exhaust air flow through said machine chamber as a door of said machine chamber is opened to remove residual cleaning solvent vapors,

wherein said actuator valves are connected between said machine chamber and said lines which supply and remove cleaning fluid to and from said machine chamber.

Brief Description of Drawings

The invention will be described with reference to the attached drawings which are given by way of non- limiting examples only, in which:

Figure 1 is a schematic view of a drycleaning machine. Figure 2 is a schematic view of the machine cylinder of Fig. 1 and solvent supply and removal lines and drying air and vapor removal lines.

Figure 3 is a schematic view of the machine cylinder of Fig. 1 and the vapor exhaust system. Figure 4 is a schematic view of the machine cylinder of Fig. 1 and a control system according to one embodiment of the present invention.

Best Mode for Carrying out the Invention

The present invention is directed to a system which reduces the residual concentration of cleaning solvent vapors in drycleaning equipment. More particularly, the present invention is directed a reducing the residual concentration of cleaning solvent vapors when drycleaning equipment is opened for loading and unloading articles to be cleaned.

According to the present invention residual cleaning solvent vapors are vented from drycleaning equipment as the equipment is opened. The present invention accomplishes a high degree of residual solvent vapor

containment by using a combination of isolation and removal .

Isolation according to the present invention is accomplished by closing all solvent lines which connect to the machine cylinder of a drycleaning machine. Isolation is achieved by providing actuator valves, e.g. solenoid valves, within each of the solvent feed and solvent removal lines. Preferably, the actuator valves are positioned in the solvent lines as close to the machine cylinder as possible to provide thorough, instantaneous isolation of the machine cylinder when the valves are actuated to close. One of the goals in positioning the actuator valves as near the machine cylinder as possible is to reduce dead space within the solvent lines which is difficult to vent. It is most preferred for provide the actuator valves between the machine cylinder and each of the solvent feed and solvent removal lines.

Isolation is also achieved by provided dampers or actuator valves, e.g. solenoid valves, in drying air supply and vapor removal lines which connect to the machine cylinder. As in the case of the solvent feed and removal lines, it is preferred to provide the dampers or actuator valves in the drying air and vapor removal lines as close to the machine cylinder as possible to minimize dead space. It is most preferred for provide the-dampers or actuator valves between the machine cylinder and each of the drying air supply and vapor removal lines.

Once the actuator valves and dampers are closed, residue solvent vapor removal is accomplished by applying an exhaust suction to the machine cylinder. Preferably, the suction is applied as the machine door is opened. This can be achieved by the use of an interlock or switch on the machine door which activates the exhaust system only when the machine door is opened. An interlock could

also function to prevent the machine door from being open until after the drying cycle is finished.

The exhaust suction used to remove residual solvent vapor can be provided by either connecting the machine cylinder to a constant suction, i.e. an exhaust fan system connected to one or more drycleaning machines, or by activating an exhaust fan connected to a particular drycleaning machine or bank of machines. The exhaust fan(s) can be designed to pass residual solvent vapors outside a building housing the drycleaning machine (s) . More preferably, the exhaust fan(s) can be connected to a solvent vapor containment/collection or recovery system. For example, the exhaust fan(s) can deliver removed solvent vapor to a bed of a suitable adsorbent such as activate carbon.

The actuator valves in the solvent lines, the dampers (or actuator valves) in the drying air and vapor removal lines, the exhaust suction means (exhaust fan(s) ) , and the machine door interlock can be completely automated and controlled by a simple processor which can also control the solvent feed cycles. Alternatively, the actuator valves, dampers, suction means, and door interlock can be sequentially activated by a three- position manual switch or by operating a bank of switches manually.

Figure 1 is a schematic perspective diagram of a drycleaning machine according to one embodiment of the present invention. The drycleaning machine of Fig. 1 includes a housing 1 in which is located within machine cylinder 2. The machine cylinder 2 contains a machine cage 3. The machine cylinder 2 and machine cage 3 are of conventional design. In use, the machine cylinder 2 receives and contains cleaning solvents which are fed therein and removed therefrom by supply and removal lines discussed below. The machine cage 2 is rotatable within

the machine cylinder 2 according to known means. In use, articles to be drycleaned are loaded within machine cage

3.

A door 4 is provided on one side of the drycleaning machine. The door 4 opens and closes by pivoting about a hinge member 5. When closed, the door

4 provides a sealing relationship with machine cylinder 2 so that cleaning solvents do not leak out of the door 4. The door 4 also includes a latch which is not shown and/or an interlock which is discussed below.

Figure 2 is a schematic view of the machine cylinder 2 of Fig. 1 and solvent supply and removal lines, drying air supply and vapor removal lines. As shown in Fig. 2, one or more cleaning solvent feed lines 6 (one shown) and one or more cleaning solvent removal lines 7 (one shown) connect between a conventional solvent supply/recovery unit (not shown) and the machine cylinder 2.

Also shown in Fig. 2 is a drying air supply line 8 and a solvent vapor removal line 9. It is to be understood that more than one drying air supply and solvent vapor removal line could be incorporated. According to conventional drycleaning machine operation, cleaning solvents are supplied to the machine cylinder 2 through the solvent feed lines 6 prior to and/or during the cleaning process. During the cleaning process the machine cage 3 rotates within machine cylinder 2 to provide a mechanical action on the articles to be cleaned. After the cleaning process, cleaning solvents

(liquid) are removed from the machine cylinder 2 through solvent removal lines 7. After the cleaning solvents are removed, the drycleaning machine proceeds to the drying process in which residue cleaning solvent vapors are removed from the articles to be cleaned. During the drying process, drying air is supplied to the machine cylinder 2 through drying air supply line(s) 3 and

solvent vapors are removed through the solvent vapor removal line(s) 9 in a known manner.

As depicted in Fig. 2 each of the solvent feed lines 6, solvent removal lines 7, drying air supply lines 8 and solvent vapor removal lines 9 includes an actuator valve (or damper) lOa-lOd which can be activated to be open or closed. In the open position the respective lines are in fluid communication with the interior of the machine cylinder 2. In the closed position the respective lines are isolated from the interior of the machine cylinder 2. Figure 3 is a schematic view of the machine cylinder of Fig. 1 and the vapor exhaust system.

As depicted in Fig. 3, an exhaust conduit 11 is in fluid communication with the interior of the machine cylinder 2. The exhaust conduit 11 is connected to a suitable exhaust suction means such as exhaust fan 12. According to studies preformed during the course of the present invention, it as been determined that the exhaust suction means or exhaust fan should draw a ventilation air flow of approximately 100 feet per minute or more through the machine door 4 when the door is in the open position. This ventilation flow rate is based upon a machine cylinder having an internal volume of approximately 17 cubic feet. The ventilation air flow should be appropriately adjusted for the size of the machine cylinder, based upon this rate which is applicable to most commercial machines.

As discussed above, the exhaust suction used to remove residual solvent vapor can be provided by either connecting the machine cylinder 2 to a constant suction, i.e. an exhaust fan system connected to one or more drycleaning machines, or by activating an exhaust fan connected to a particular drycleaning machine or bank of machines. The exhaust fan(s) can be designed to pass residual solvent vapors outside a building housing the

drycleaning machine (s). More preferably, the exhaust fan(s) is connected to a solvent vapor containment/collection or recovery system. For example, the exhaust fan(s) can deliver removed solvent vapor to a bed of a suitable adsorbent such as activate carbon. In Fig. 3 a switch 13 is depicted as being position in near the opening 14 of the machine cylinder 2 at a position wherein it can be activated when the machine door 4 is opened and closed. According to one embodiment of the present invention, the exhaust suction means, e.g. exhaust fan 12, is activated when the machine door 4 is opened and switch 13 is activated. Switch 13 can also include an interlock mechanism which prevents the machine door 4 from being opened when the drycleaning machine is cycling through the cleaning and drying cycles.

Figure 4 is a schematic view of the machine cylinder of Fig. 1 and a control system according to one embodiment of the present invention. Drycleaning machines are generally equipped with control processors which control the cleaning/drying cycles and fluid

(liquid and gaseous) flow during these cycles. The control of the actuator valves and/or dampers, suction means (e.g. exhaust fan), and door switch use according to the present invention can be controlled by a simple processor 15 which can also control the overall drycleaning process.

The present invention is applicable to a variety of conventional drycleaning machines, including closed circuit machines and exhausting machines, single and multiple bath processing machines. These and other types of machines can either be designed with the actuator valves, dampers, suction means, and control of the present invention. It is noted that although the preferred position of the actuator valves and dampers is immediately adjacent the machine cylinder the actuator

valves and dampers can also be conveniently supported anywhere within the machine housing. It is also possible to have a control means for the isolation and residual solvent vapor removal elements of the present invention which is separate from the main control system of the drycleaning machine. Such a control means could be activated by the operator after the drycleaning process is finished.

As discussed above, in operation, after the drying cycle is finished, isolation of the machine cylinder is achieved by closing the actuator valves and dampers in the solvent supply and removal lines and in the drying air and solvent vapor removal lines. Once isolation is achieved, the machine door is opened and simultaneously, the suction means creates a ventilation flow to exhaust residue solvent vapors.

Although the present invention has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the present invention and various changes and modifications may be made to adapt the various uses and characteristics without departing from the spirit and scope of the present invention as described by the claims which follow.