Memory, and filter equipped with communication device and concentration sensor

The present invention relates to systems and methods for measuring the concentration of substances in filter elements.

The use of wireless communication is widespread in asset management, especially in inventory management applications. For example, RFID tags can be used to monitor manufacturing lines and to monitor the movement of manufacturing lines, assets, or parts via the supply chain. To explain this concept more clearly, in a manufacturing company, RFID tags are attached to each part that enters the manufacturing equipment, and the parts with the RFID tags attached are sent to the manufacturing process and combined with other parts under the manufacturing process. It is made into a subassembly and is finally finished as a product. RFID tags allow manufacturers to track the movement of specific parts throughout the manufacturing process, as well as identify specific parts, including any particular assembly or finished product.

The use of RFID tags is also endorsed within the pharmaceutical and pharmaceutical industries. The U.S. Food and Drug Administration submitted a report in February 2004 supporting the use of RFID tags for labeling and monitoring drugs, with the aim of pedigree the drug as well as the market and consumers. The purpose is to limit the mixing of fake prescription drugs.

Since its introduction, RFID tags have been used in a number of applications, such as identifying filter products and providing information for process control of such products. U.S. Pat. No. 5,674,381 discloses the use of "electronic labels" in combination with filtration equipment and replaceable filter assemblies. More specifically, this US patent describes an electronically labeled filter with read / write memory and an associated filtration device with label responsive reading means. The electronic label counts and stores the working time of the replaceable filter, and the filtration device uses or disallows the filter based on this real-time value. The US patent also states that electronic labels can be used to store identification information about interchangeable filters.

U.S. Patent Application Publication No. 2005/0205658 discloses a process equipment tracking system. This system includes RFID tags for use in combination with process equipment. RFID tags are described as capable of storing "at least one event". Such traceable events include wash dates, batch process dates, and so on. This document also describes a personal computer with a database of process equipment or an RFID reader that can connect to the Internet. The process device database contains a large number of traceable events and can provide useful information in determining the "life of the process device based on accumulated data". This document includes the use of this type of system with a variety of process equipment such as valves, pumps, filters and UV lamps.

U.S. Patent Application Publication No. 2004/0256328 describes devices and methods for monitoring the integrity of filtration facilities. This document describes the use of a filter that houses an onboard memory chip and a communication device in combination with a filter housing. The filter housing acts as a monitoring tester and an integrity tester. The document also discloses the use of a set of steps to ensure the integrity of the filtration elements used within the multi-round housing, which steps include the type of filter used, limit data values, It includes issuing a processing request (query) for confirming the manufacturing public data to the storage element.

Even with the improvements obtained by using RFID tags, there are still areas where the effect is not sufficient. For example, there are many applications in which it is extremely useful to monitor the concentration of a particular substance in real time, for example, integrity testing or protein monitoring. Although RFID tags are an embodiment of the present invention, solutions using wired communication are also included in the scope of the present invention.

<p><patcit num="1"><text>U.S. Pat. No. 5,674,381</text></patcit><patcit num="2"><text>U.S. Patent Application Publication No. 2005/0205658</text></patcit><patcit num="3"><text>U.S. Patent Application Publication No. 2004/0256328</text></patcit><patcit num="4"><text>US Provisional Patent Application No. 60 / 725,238</text></patcit></p>

<p> It is to provide a system and method for accurately measuring the concentration of a substance in a filter element, which solves a drawback in the conventional system and method.</p>

<p> According to the system and method of the present invention for accurately measuring the substance concentration in the filter element, the shortcomings in the conventional system and method are solved. In one embodiment of the system of the present invention, a sensor capable of measuring the concentration of a specific substance and a communication device are connected, and the concentration of the specific substance can be measured and transmitted near a filter element in use. Is. The system may include a single component that integrates a communication device and a sensor. Alternatively, the system may include individual sensors and transmission components that communicate with each other. In yet another embodiment, a storage element is added to the system, which allows the device to store a set of concentration values. In yet another embodiment, the electrical components are wirelessly actuated. The device can be beneficially used for many applications. For example, the newly developed integrity test is based on the concept of adding tracer gas to the carrier, and if this tracer gas is detected, its sensitivity will be much higher than that in a standard diffusion test. It would be very beneficial to be able to detect the gas and transmit the result outside the filter housing. In another application, if the protein concentration in the filter housing can be monitored, the operating conditions can be adjusted so that the protein concentration at the membrane surface position is maintained for high reliability and reproducibility.</p>

<p> Systems and methods for accurately measuring the concentration of substances in filter elements that solve the shortcomings of conventional systems and methods are provided.</p>

<figref num="1">It is the schematic of the Example of this invention.</figref>

FIG. 1 illustrates a typical filtration system according to the present invention, in which the filter element 10 is surrounded by a housing 20. The filter element can be a simple, pleated, paper-like porous material. Alternatively, the filter element can consist of a more complex frame, such as a plastic, and a porous material. The sensor 30 (hereinafter, also referred to as a density sensor) is embedded in the filter element in close proximity to the filter element 10 and preferably in the filter element. The sensor 30 can generate a fluctuating output as a function of ambient concentration. This output can take the form of analog voltage or current values, or their digital values or pulses, which in a preferred embodiment change linearly with concentration, under the conditions of the present invention. However, it can be of an arbitrary output form having a known relationship such as logarithmic or exponential with respect to the ambient concentration, in which case the output value is converted to determine the measured concentration.

In one embodiment, the sensor 30 is embedded downstream of the filter element 10, and in other applications where the concentration of interest is uniform, the position of the filter element is not important and is limited to anywhere downstream of the filter element, eg. However, it can be on the inner surface of the filter element or in the common outlet. In applications where the concentration varies and is not uniform, the concentration sensor can be positioned close to the outlet of the filter element. In another embodiment the concentration sensor 30 may be positioned within the common outlet. In some applications, the temperature of the filter element can exceed 145 ° C, so sensors that can withstand such temperatures should be used. Similarly, the temperature cycle in the housing 20 can be such that it goes from cold to hot and then back to cold, so the concentration sensor should be able to withstand such temperature cycles. Concentration sensors have numerous examples, such as solid-state devices that use specific formulations that are known to interact with the desired gas in some applications. The hydrogen sensor embodiment uses a MOS diode, the metal alloy layer contains a PdAg alloy, and SiO₂The oxide and the semiconductor inside are silicon. Hydrogen affects the junction between the metal and the oxide layer, changing the diode properties there, and this change in the junction is converted to concentration levels.

In another example, the oxide is SnO₂A thick film-like metal oxide semiconductor device is used. The presence of an oxidizing gas near the sensor changes the resistance characteristics of this device, allowing the gas concentration to be determined. Yet another sensor uses infrared (IR) diffusion to detect a particular substance. In these sensors, the IR beam is directed at the receiver. Certain substances of interest, such as gases, absorb some of the IR radiation as it is sent from the transmitter to the receiver, the amount of which is related to the concentration of the substance. IR and UV light can typically be used in combination with fiber optic cables to measure solute concentrations using refraction. Other types of sensors include affinity-based sensors based on optical, electrical, or piezoelectric detection methods. One such affinity-based sensor uses a microbalance with a suitable ligand. When the substance of interest is attached to and attached to the ligand, the mass on the microbalance is slightly increased, and this slightly increased mass is the concentration based on the flow rate. Converted to rate). These examples are intended to illustrate some of the available sensor types and do not cover all of such suitable concentration sensors.

The transmitter 40 is also positioned near the sensor 30 or integrated with the concentration sensor. In a preferred embodiment, the transmitter 40 is encapsulated in one integral part together with the concentration sensor 30. Alternatively, the transmitter 40 and the sensor 30 may be separated and communicated with each other via such as an electrical signal. The communication device can be of various types, and in one embodiment wireless communication is used, in which case it is preferable to use an RFID tag. RFID tags are active and can communicate with readers on a regular basis. Alternatively, a passive RFID tag can be used to obtain energy for transmission and concentration detection from an electromagnetic field transmitted by an RFID reader. In another embodiment, a wired communication device is used between the sensor and the control module outside the housing.

Optionally, a storage element 50 combined with a transmitter 40 and a density sensor 30 can be used. The storage element 50 can be a random access memory (RAM) or a flash EPROM device, but can be used to store a set of density readings such as those that can be generated by periodic sampling of the sensor. This makes it possible to make the data transmission speed of the transmitter 40 different from the density sampling speed. For example, the concentration can be sampled 10 times per second and the data transmitted during that time can be sampled only once. In one embodiment, a wireless receiver 60 for communicating with a transmitter is used located outside the housing 20. In a preferred embodiment, an RFID reader or base station is used, but the RFID reader can be configured to query the transmitter at regular intervals, or read at the request of the equipment operator. Can be manually manipulated to carry out. In another embodiment, the wireless receiver 60 may also have a storage element, but in this case the complexity required for the device in the housing is reduced. In this embodiment, the wireless receiver preferably issues processing requests to the wireless transmitter / concentration sensor at regular intervals, receives the latest density sensor measurements as determined at that time from the wireless transmitter, and then stores the values. Stored in the element. The capacity of the storage element is variable and can be determined based on various factors, but these factors include, but are not limited to, the reception speed of measured values, the process processing speed of stored data, and the storage element. The frequency of communication with the external environment is included.

Taking a filter element such as an RFID tag in which a transmitter 40 is coupled to a density sensor 30 as an example, an RFID tag is a passive type that transmits data only when there is a processing request from a wireless receiver or a base station. Yes, the wireless transmitter that receives such a processing request transmits the concentration value currently available from the concentration sensor 30. These concentration values are optionally stored in, for example, a log file with the relevant time stamps by a wireless receiver connected to a computing device such as a computer. In another scenario where the wireless receiver is assumed to be separated from the computer, the wireless receiver needs to store a number of concentration measurements internally, for example, until it is connected to the main computer and / or storage device. Therefore, it is necessary to integrate the storage element into the wireless receiver.

A mechanism for transmitting a radio signal to the outside of the housing has been conventionally disclosed and is well known in the art. U.S. Patent Application Publication No. 2004/0256328 describes the use of an antenna that relays information between a transponder located in a filter housing and a monitoring and testing unit outside the housing. The defined physical structure of the present invention is useful in many applications, some of which are described below, but are not intended to list all of these applications.

In one embodiment, the invention is used in combination with an in-situ integrity test. This process allows the operator to verify the integrity of the filter in the housing filter at the customer site without additional equipment. In one embodiment, a tracer gas such as helium or hydrogen is added to the carrier and the tracer gas is injected into the system. A sensor, preferably a solid-state gas sensor capable of measuring the tracer gas concentration, is preferably positioned downstream of the filter to measure the tracer gas breakthrough value. This sensor can optionally be protected by a hydrophobic filter to prevent adhesion of proteins and other substances. The tracer gas concentration at a particular transmembrane pressure in operation indicates the presence of bubble point pores within the filter and the completeness of the filter, thus establishing pass / fail criteria for each filter type. This test displays bubble points and defects much more sensitively than the standard diffusion test and is applicable to any filter, but most ideally it is a vertical flow parvovirus (NFP) filter. It is suitable for.

In the second embodiment, two gases are introduced into the filter housing in a known ratio. This example is described in US Provisional Patent Application No. 60 / 725,238. In a preferred embodiment, the filter element is moistened with a suitable liquid and the selected gas has different transmissions within this liquid. The gas used can be a noble gas, a perfluorinated gas, or one having a variety of component compositions including carbon dioxide. Since these gases have different permeability, they pass through the filter element at different velocities, and thus their ratio on the downstream side of the filter element is different, so that the integrity of the filter element is confirmed based on this ratio. By using one or more concentration sensors, it is possible to monitor such ratios on the downstream side.

The second application of the present invention relates to protein monitoring. In this scenario, the filtration process is controlled using sensors that can measure the concentration of solutes, most preferably proteins. In this application, the sensor may be an optical fiber capable of measuring the amount of ultraviolet or infrared passage, an affinity-based sensor based on optical, electrical or piezoelectric detection methods, or an affinity-based sensor using a microbalance and a suitable ligand. It is preferable that it is one of the sensors of. In traditional flow filtration (TFF) applications, the sensor is positioned on the surface of the filter, preferably at the outlet end of the flow channel, physically integrated with the filter. In this way, the sensor can measure the protein concentration at the membrane surface position. Based on the concentration readings at this position, operating conditions such as transmembrane pressure can be adjusted to maintain protein concentrations at specific levels. This type of control is particularly suitable for tangential flow filtration where the concentration boundary layer accumulates on top of the filter membrane. Since both the flux and sieving actions of the membrane are determined by the wall surface concentration of the deposited protein, the protein concentration at the membrane wall position can be maintained within a specific range by changing the transmembrane pressure. During operation, the sensor 30 measures the concentration, the measured concentration value is transmitted to the outside of the filter housing by the transmitter 40, and the transmitted concentration value is received by the external receiver 60. The desired latest transmembrane pressure is calculated based on the current concentration and the received concentration measurement using a conventional control loop that uses an algorithm such as proportional integral differential (PID) control or proportional integral (PD) control. This new value can be applied to the system. In one embodiment, a plastic filter housing is used, which allows concentration data transmission by a wireless transmitter through the housing at any time.

10 Filter element 20 housing 30 Concentration sensor 40 transmitter 50 Memory element 60 wireless receiver