Laboratory apparatus comprising a UV radiation device, and disinfection method for a laboratory apparatus

Abstract

The present invention relates to a laboratory apparatus, comprising a UV radiation device which has at least one UV lamp to carry out a disinfection process, and a control device to control the UV lamp, wherein the control device is designed to specify a duration (t) during which the UV lamp is operated during the disinfection process. The control device is designed to specify the duration (t) using a control function stored in the control device as a function of the operating time (d) of the UV lamp, in such a manner that the duration (t) increases with increasing operating time (d). The present invention further relates to a method for operating such a laboratory apparatus.

Claims

1. A laboratory apparatus, comprising: a UV radiation device which has at least one UV lamp configured to carry out a disinfection process, and a control device configured to control the at least one UV lamp, wherein the control device is designed to specify a duration (t) during which the at least one UV lamp is operated during the disinfection process, wherein the control device is designed to specify the duration (t), using a control function stored in the control device, as a function of the operating time (d) of the at least one UV lamp, in such a manner that the duration (t) increases with increasing operating time (d).

2. The laboratory apparatus according to claim 1, wherein a target operating time (d.sub.S) is stored in the control device, and corresponds to an operating time in which the radiation intensity (I) essentially corresponds to a target radiation intensity (I.sub.S), and the nominal radiation intensity of the at least one UV lamp, and the control device is designed to implement the prolongation of the duration (t) starting at the target operating time (d.sub.S).

3. The laboratory apparatus according to claim 2, wherein a maximum operating time (d.sub.Max) is stored in the control device, and corresponds to a maximum life defined by a manufacturer of the at least one UV lamp, and the control device is designed to implement the prolongation of the duration (t) in the period of time between the target operating time (d.sub.S) and the maximum operating time (d.sub.Max).

4. The laboratory apparatus according to claim 3, wherein the prolongation of the duration (t) as a function of the operating time (d) follows a linear function.

5. The laboratory apparatus according to claim 4, wherein the linear function is defined by the target radiation intensity (I.sub.S) at the target operating time (d.sub.S) being set as 100%, a maximum radiation intensity (I.sub.Max) at the maximum operating time (d.sub.Max) being determined as x % (<100%), and a linear reduction in the radiation intensity being assumed between the two vertices, wherein for each given operating time (d) in the range between the target operating time (d.sub.S) and the maximum operating time (d.sub.Max), a correction factor for the prolongation of the period (t) is taken from the linear function.

6. The laboratory apparatus according to claim 5, wherein the duration (t) at an operating time (x), which lies in a period of time between the target operating time (d.sub.S) and the maximum operating time (d.sub.Max), is defined by the formula $t_x=t_s+t_s\left(\frac{I_S-I_{\mathrm{Max}}}{I_S}\right)\left(d_x-d_s\right)/\left(d_{\mathrm{Max}}-d_s\right)$ where t.sub.S represents a duration set for the disinfection process when the at least one UV lamp has not yet reached the target operating time (d.sub.S).

7. The laboratory apparatus according to claim 4, wherein the linear function is defined by a best-fit line which is determined from measured values of the radiation intensity in the range between the target operating time (d.sub.S) and the maximum operating time (d.sub.Max).

8. The laboratory apparatus according to claim 1, wherein the laboratory apparatus is a climate chamber comprising one of an incubator, a drying cabinet, a laboratory refrigerator, a fume hood, or a safety cabinet.

9. A method for operating a laboratory apparatus according to claim 1, wherein the control device determines, using the control function stored in the control device, the duration (t) as a function of the operating time (d) of the at least one UV lamp, wherein the duration (t) increases with increasing operating time (d), and the at least one UV radiation device carries out the disinfection process for the determined duration (t).

10. The method according to claim 9, wherein a target operating time (d.sub.S) is stored in the control device, and no prolongation of the duration (t) takes place until the target operating time (d.sub.S) is reached.

11. The method according to claim 9, wherein the UV radiation device, after a maximum operating time (d.sub.Max) has been exceeded, carries out disinfection processes with the same duration (t) as calculated for the time point at the maximum operating time (d.sub.Max) with a time corresponding to the formula $t_x=t_s+t_s\left(\frac{I_S-I_{\mathrm{Max}}}{I_S}\right).$

12. The method according to claim 11, wherein when the maximum operating time is reached, a corresponding warning in the form of an optical and/or acoustic signal is output to the user.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be described in more detail below with reference to drawings. The drawings are merely illustrative of some preferred embodiments to which, however, the present invention is not limited. The figures are schematic. Like reference numerals designate like parts, wherein all parts are not always provided with a reference numeral. In the drawings:

(2) FIG. 1 shows a perspective view of a laboratory apparatus according to the present invention, using the example of a safety cabinet;

(3) FIG. 2 shows a diagram for four different UV lamps, in which their service life is plotted against the UV-C radiation intensity;

(4) FIG. 3 shows a diagram in which, for the values of lamp 1 of FIG. 2, the operating hours are plotted against the decrease in the radiation intensity, and

(5) FIG. 4 shows the simplified diagram of FIG. 3 as a linear function.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows exemplary laboratory apparatus 1 using the example of a safety cabinet. It has a housing 10 which surrounds a working space 11, which is accessible to a user via a front opening 12 which can be closed by a sliding pane. The safety cabinet is used, for example, for processing biological or microbiological samples. These can result in contamination of the working space 11. So that it is possible to kill off any germs, such as bacteria, viruses, spores, or yeasts that may have entered the working space, a UV radiation device 2 is included in the safety cabinet. In the example shown, it comprises two UV lamps 20 which are arranged on a side wall of the housing 10 on the side facing the working space 11. A control device 3, which is connected to the lamp 20, is included to control the operation of the UV radiation device 2.

(7) Disinfection processes can be initiated from time to time by the user of the safety cabinet by inputting an appropriate command into the control device 3 via an input device 30 (in this case, a touchscreen). The control device can also be set up to remind the user at certain intervals that a disinfection process should be carried out. For example, a corresponding message is displayed on a display 31 (here in the form of a touchscreen) or a similar display device. If the user initiates a disinfection process by a corresponding input, it can be carried out immediately following the command or with a time delay, by the UV lamps 20 being operated for a predetermined duration. A timer 32 integrated in the control device 3 ensures the duration is observed. During operation, the UV lamps 20 emit UV radiation, particularly UV-C radiation, having a wavelength of 254 nm into the working space 11 of the safety cabinet 1.

(8) The duration of the disinfection process at the beginning of the operating life of the UV lamps, which are assumed below to be the same type of lamp with the same operating time, is prespecified and stored in a memory 33 of the control device 3 by the user depending on the type of germs to be killed in the working space 11. In principle, however, it would also be possible for the manufacturer to specify a specific initial duration in the control device, which can optionally be overwritten by the user by his own input. This initial duration is valid up to a target operating time of the UV lamps and is referred to below as t.sub.S.

(9) The target operating time depends on the type of UV lamps used and denotes the operating time within which UV lamps generate the desired radiation intensity, in particular, the nominal radiation intensity, or deviate only slightly from it. The target radiation intensity can be determined inter alia from data which is usually provided by the lamp manufacturer. Alternatively, the target operating time can be determined by measurements on-site. FIG. 2 shows an example in which the target operating time is determined by utilizing a service life diagram of the lamp manufacturer. In FIG. 2, the service life is plotted in hours for four different UV lamps, which are referred to as lamp 1 to lamp 4, against the UV-C radiation intensity, each at a distance of 10 cm to the irradiated surface. The diagram thus illustrates for each lamp the change in the radiation intensity with increasing operating time. As can be seen, the radiation intensity for each of the lamps continuously decreases after a certain service life. From this point on, it is advisable to prolong the irradiation time in order to compensate for this decrease in radiation intensity and to ensure sufficient disinfection. The target operating time is set to a corresponding value.

(10) Below, the further procedure is described in more detail using the example of lamp 1. The profile of the radiation intensity with respect to the service life of the lamp, as shown in FIG. 2, is shown in FIG. 3 as a decrease in the radiation intensity in percent over the operating hours (the service life and/or operating time). As can be seen from the curve, the UV lamp (lamp 1) initially needs a break-in period in which the radiation intensity initially decreases, until the maximum radiation intensity has been reached after about 2000 operating hours. From that point on, the radiation intensity continues to decrease until, at an operating time of 10,000 hours, it decreases by 20% compared to the maximum radiation intensity. From this point on, it no longer makes sense to continue to operate the UV lamp. An operating time of 10,000 hours is therefore defined as the maximum operating time d.sub.Max of the lamp 1. The target operating time d.sub.S is set to 2000 operating hours.

(11) According to one embodiment of a variant of the present invention, which will be described herein, the duration is prolonged to compensate for the loss of radiation intensity in the period of time between the target operating time and the maximum operating time. In principle, the profile shown in FIG. 3 could be utilized as a function for the correction of the duration. However, this would add complexity, and such high accuracy is generally not necessary in calculating the time correction. For this reason, it is preferred according to the present invention to represent the profile of the decrease in radiation intensity with respect to the operating time with a simple, linear function.

(12) This simplified relationship is shown graphically in FIG. 4. As can be seen, the function initially has a horizontal segment during an operating time from 0 to 2000 hours. In this time period, the duration of the radiation is not corrected; the duration corresponds to the prespecified duration t.sub.S. At an operating time of over 2000 hours, up to the maximum operating time of 10,000 hours, on the other hand, the duration is prolonged, starting from the original duration t.sub.S. For any operating time d.sub.X in the time period d.sub.S to d.sub.Max, the relationship shown in FIG. 4 results in an associated decrease in the radiation intensity, which is to be compensated by a corresponding prolongation of the duration. The corresponding correction factor can be calculated as

(13) $\left(\frac{I_S-I_{\mathrm{Max}}}{I_S}\right)\left(d_x-d_s\right)/\left(d_{\mathrm{Max}}-d_s\right)$
where I.sub.S is the radiation intensity at the target operating time and I.sub.Max is the radiation intensity at the maximum operating time. The difference between I.sub.S and I.sub.Max is given in FIGS. 3 and 4 as I.sub.Max and amounts to 20% in the example, resulting in a multiplier of 0.2. This results for the operating time period from d.sub.S to d.sub.Max in a duration t.sub.X, which is calculated according to the following formula:

(14) $t_x=t_s+t_s\left(\frac{I_S-I_{\mathrm{Max}}}{I_S}\right)\left(d_x-d_s\right)/\left(d_{\mathrm{Max}}-d_s\right)$
Based on this calculation formula, the control device calculates the duration for which the UV lamps are operated if their operating time is in the period between the target operating time and the maximum operating time. The current operating time of the UV lamps is determined by means of a timer 34, which is integrated into the control device 3.

(15) After the maximum operating time has been reached, the UV lamps should be replaced. To ensure this happens, the control device 3 can be designed to block any further start of a disinfection process until new UV lamps have been inserted into the UV radiation device. However, in this case there is a risk that the safety cabinet will continue to be used without disinfection, which can endanger the processed samples and the user. For this reason, it may be useful to continue to allow disinfection processes after the maximum operating time of the UV lamps has been reached. In this case, it also makes sense to continue to provide compensation for the loss of radiation intensity. In a variant of the present invention, therefore, the prolongation of the duration also takes place after the maximum duration has been exceeded, specifically, with the same correction factor that is applied for the maximum operating time. At this point, the duration accords with the formula:

(16) $t_x=t_s+t_s\left(\frac{I_S-I_{\mathrm{Max}}}{I_S}\right)$
which in the specific example means a prolongation of 0.2 t.sub.S. The user is informed that the maximum operating time has been reached by the display 31 of the device (as a touch screen on the front of the housing, in this case), and he is asked to replace the UV lamps 20. Additional information on the disinfection process, for example, whether a time prolongation is already being used, and the status of the UV lamp, can also be shown on the display. The control device 3 can also be programmed to allow the user to intervene and make corrections in the process flow, such as the already-described input or change of the (standard) duration t.sub.S or the corrected duration t.sub.X. The present invention ensures in the manner described that a reliable disinfection takes place without this requiring early replacement of the UV lamps, increased energy consumption, or additional difficulty for the user of the laboratory apparatus.

(17) While the present invention has been illustrated by description of various embodiments and while those embodiments have been described in considerable detail, it is not the intention of Applicants to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily appear to those skilled in the art. The present invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicants' invention.