JPH0373308B2 - - Google Patents

Description

Claim 1: from at least one fluid source suitable for containing a medical fluid to a fluid receiving container suitable for receiving fluid from the fluid source; a fluid transfer and monitoring device for delivering a predetermined amount of fluid through a propulsion means operatively suitable for transfer to a receptacle, the fluid transfer and monitoring device comprising: a second weight of the fluid receiving container at a second time point subsequent to the first time point; and means for comparing the first and second weights. , responsive to the comparing means, initiating an alarm when the second weight is not greater than the first weight;
A fluid transfer and monitoring device comprising alarm means for indicating the absence of fluid flow from said fluid source to said receiving vessel.

2 a sensing means for sensing operation of the propulsion means; and a sensing means for starting detection of the first weight and the second weight in response to the sensing means sensing the operation of the propulsion means; The apparatus of paragraph 1 comprising:

3. The apparatus of claim 2, wherein the sensing means includes weight sensing means for sensing the weight of the receiving container.

4. The device according to clause 3, wherein the weight sensing means is a load cell.

5. The device according to item 3, wherein the weight sensing means is a histometer.

6. The comparison means includes another comparison means for comparing the first and second weights against a predetermined weight change, and the alarm means is configured to detect a weight change between the first and second weights. 4. The apparatus of claim 3 including low flow indicator means for indicating low flow when said predetermined weight change is less than said predetermined weight change.

7. The method of claim 6, wherein the alarm means further includes high flow indicating device means for indicating high flow when the weight change between the first and second weights is greater than the predetermined weight change. Device.

8. The apparatus of claim 7, including delay means for determining said second point in time after said first point in time.

9. said propulsion means is operated at a first operating speed for delivering a portion of said predetermined weight; said propulsion means is operated at a lower operating speed than said first operating speed for delivering a last portion of said predetermined weight; 8. Apparatus according to clause 7 operated at a second operating speed.

10. The apparatus of claim 9, wherein the second operating speed delivers a small amount of fluid in pulses for the last portion of the predetermined weight to accurately obtain the predetermined weight.

11. The apparatus of paragraph 1, paragraph 2 or paragraph 6, wherein a plurality of solution sources are provided.

BACKGROUND OF THE INVENTION The present invention relates to fluid transfer and monitoring devices for delivering predetermined amounts of fluid.
More particularly, the present invention relates to a device for direct measurement and control of the precise amount of fluid being transferred.

Hospitals, pharmacies, and laboratories are required to deliver predetermined amounts of fluid to be analyzed to fill unit dose syringes, medical containers, or other containers with the same repeatable amount. It is important to maintain high accuracy, cleanliness and sterility during these operations. Moreover, in order to use personnel efficiently and to minimize costs without sacrificing quality, high productivity is desirable, as well as high accuracy, cleanliness and indestructible standards.

Known manual devices and methods for transferring fluids utilize a transfer system that includes a receiving vessel and a Y-shaped transfer set. The Y-transfer set includes two separate tubes, each having one end connected to a common junction, through which solution pumped passes into a receiving vessel. Will. The other end of one tube of the set is connected to one solution container, and the other end of the other tube of the set is connected to another solution container. The desired volume of each solution being transferred to the receiving vessel is controlled by a clamp placed on each tube. The solution is allowed to flow into the receiving vessel by gravity flow. However, it has been found useful to transfer the solution under the influence of a vacuum applied to the receiving vessel. When the receiving container is a flexible plastic container, a vacuum is created within the vacuum chamber in which the container is placed.

In the past, it has been known that in order to ensure sterility during the transfer of solutions, the operation should be carried out under a laminar flow hood. Laminar flow hoods are used to reduce the risk of airborne contamination of such solutions. These units operate by taking room air and passing it through a prefilter to remove bulk contaminants such as dust and lint. The air is then compressed and directed in a laminar flow manner through a bacteria-blocking filter in a hood. The purified air flows out in parallel lines at a uniform rate over the entire working surface of the hood. The bacteria inhibiting type filter is designed to remove all bacteria from the air being filtered.

Transferring solutions under a laminar flow hood helps prevent airborne contamination, but it is relatively cumbersome and expensive, and it is difficult to eliminate other sources of contamination, such as contamination caused by handling. would not be useful. When using hoods, workers may inadvertently perform work at the edge or outside of the hood rather than within the recommended space of at least 6 inches within the hood to ensure the benefit of purified air. . Time and care must be taken to maintain a direct open path between the filter and the blending area. Solution bottles and other non-sterile objects should be placed at the rear of the hood work area following the filter, as these objects can contaminate everything downstream and disrupt the laminar flow of purified air. Can not. Also, the use of laminar flow hoods requires routine cleaning of the hood's working surfaces before compounding is performed.

Thus, the prior art manual or semi-manual devices and methods discussed above are labor-intensive, time-consuming, and their inability to fill a large number of containers involving a large number of error-prone manual operations. Disadvantageous for efficiency.

Modern machines are capable of pumping fluid at high speeds with some degree of accuracy. However, the methods employed by these machines to monitor the delivery of a predetermined amount of fluid require actual measurements of the fluid flow rate. Special purpose monitoring devices such as air detectors, ultrasound transducers, Doppler transmitters/receivers are used in measuring fluid flow rates. These devices only indirectly measure fluid flow and are therefore prone to inaccuracy and do not provide reproducible results. This, of course, is a major drawback when rapid and efficient delivery of repeatable, precise, predetermined amounts of fluid is required.

Another method of achieving accuracy in transferring predetermined amounts of fluid is through volumetric chambers. This method requires a volumetric chamber that is expensive to fabricate because of the close tolerances required to maintain an accurate volume within it. This method is also slow and interrupts the laminar flow of the fluid to be transferred. Additionally, it may influence the determination of the amount of air within the volumetric chamber that is displaced.

The device of the invention overcomes the above disadvantages. Additionally, the present invention provides actual monitoring of the fluid being transferred to achieve rapid, accurate, and reproducible fluid transfer. The present invention therefore provides high productivity while maintaining high standards for accuracy and repeatability.

Processes and apparatus in which the invention herein described may be utilized are disclosed in the article entitled "High Speed Bulk Blender" by Carl, Miller and Lawrence, Earle, Hogan, assigned to the assignee of this invention and herein incorporated by reference. Patent application No. 58-502202 filed at the same time
It is claimed and described in (Japanese Patent Publication No. 59501146).

As described therein, rapid and precise transfer of fluid is achieved by a sequentially controlled peristaltic pump operatively connected between the solution container and the receiving container. The controller receives data from the operator regarding the volumetric amount of each solution to be dispensed and its specific gravity; comparison of this data to the sensed weight in the collection container allows the controller to sequentially operate the pumps. The controller is capable of monitoring various working conditions. Failure to achieve these operating conditions results in automatic stoppage of work.

SUMMARY OF THE INVENTION In accordance with the present invention, an apparatus is provided for transferring and monitoring a predetermined amount of fluid from at least one fluid source containing a medical fluid to a fluid receiving container. . A positive propulsion means, for example in the form of a peristaltic pump or the like, is operatively connected between the fluid source and the fluid receiving vessel to effect fluid transfer. The device monitors fluid flow rate by measuring changes in fluid weight, as discussed more fully below.

The flow rate of fluid transferred to a receiving container can be expressed as the change in weight of the container times the specific gravity of the fluid divided by time. Since specific gravity and time can be defined as constants, the flow rate can be expressed as being directly proportional to the weight change. Therefore, by monitoring the weight change of the container and comparing it with predetermined working conditions, a predetermined amount of fluid can be delivered accurately and precisely, and the fluid transfer can be monitored for malfunctions. The apparatus of the invention is capable of detecting a first weight of a receiving container at a first point in time and a second weight of the receiving container at a second point in time subsequent to the first point in time. It includes sensing means, which can be a load cell, a histometer, or the like, for sensing weight. Comparison means of the device compares the first and second weights and activates an alarm when the second weight is not greater than the first weight, thereby indicating that there is no fluid flow to the receiving vessel. do.

Here, the first time point means the start point of a certain time interval, and the second time point means the end point of the time interval.

The apparatus further includes a propulsion means sensor that initiates sensing of the first and second weights when operation of the propulsion means is sensed. Further, the comparison means is the first
and further comparison means for comparing the second weight to a predetermined weight change. The further comparing means activates a high flow indicator or a low flow indicator when the change between the first and second weights is less than or greater than a predetermined weight change, thereby causing a high or low flow. Indicates the state.

The device of the present invention provides rapid, efficient and precise monitoring of fluid transfer so that accurate and reproducible predetermined amounts of fluid transfer are achieved. Furthermore, the present invention is inexpensive to manufacture and easily adaptable to a wide variety of fluid transfer systems.

[Brief explanation of drawings]

FIG. 1 is a block diagram constructed in accordance with the present invention.

FIG. 2 is a flowchart constructed in accordance with the present invention.

DETAILED DESCRIPTION Referring to FIG. 1, a device 10 incorporating a fluid flow monitor of the present invention, indicated generally by the reference numeral 12,
is schematically illustrated. The device 10 transfers fluid from supply containers 16 and 18 to a collection or receiving container 20 through a transfer medium 14, such as a flexible tube or the like. Fluid transfer is performed by a pair of pumps 22 and 24 operatively connected between each supply and receiving vessel. Pumps 22 and 24 may be of any positive fluid pumping type, but are preferably peristaltic pumps for use in aseptic applications. Device 1
0 is illustrated and described as having two supply vessels, however a single supply vessel or multiple vessels can also be used in connection with the present invention.

Device 12 monitors the flow rate of fluid being transferred from supply vessels 16 and 18 to receiving vessel 20. Device 12 includes an alarm to alert a person to no flow, low flow, or high flow in the system, thereby detecting empty supply containers, ruptured transfer tubes,
Indicates a malfunction such as a line blockage, pump malfunction, or simultaneous pump operation.

Fluid flow monitoring of the delivery of a predetermined amount of fluid is accomplished in the present invention by comparing fluid weights taken at predetermined time intervals. This can be explained by the equation of flow rate equal to weight change times a constant (specific gravity divided by time interval). This mode of flow monitoring is more accurate and more economical than indirect measurement of fluid velocity by ultrasonic transducers or the like, or by slow and expensive volumetric chamber methods.

In accordance with the foregoing conditions, a weight sensor or detector 26, such as a load cell, strain gauge, or the like, detects the weight of the receiving container and relays this information to the control module 30 via line 28. The control module 30 includes means for comparing each pair of successive weights taken at successive times to determine whether there has been an increase in weight from the previously sensed weight. If there is no weight increase, an alarm will sound and the supply container 1 will sound, indicating an empty supply container, ruptured tube, etc.
6 and 18 to the receiving vessel 20. A delay means, down counter or clock 34 is used to select the weight at a desired preselected time for use with comparison means.

Apparatus 12 further includes lines 38, 40 and 4.
2 and includes a sensor 36 operatively connected to pumps 22 and 24 through 2. A sensor 36, which may be of any electrical variety, initiates weight sensing at preselected intervals and senses operation of two or more pumps. The device 12 also includes further comparison means for comparing the difference between two successive weights at successive points in time with a predetermined weight change for a selected time period included therein. If the weight difference between two consecutive weights is less than the predetermined weight change, an alarm 44 sounds, indicating a low fluid flow condition indicating a bent tube, malfunctioning pump, etc. If the weight change exceeds a predetermined weight change, an alarm 46 will sound indicating a high fluid flow condition indicating a malfunctioning pump, simultaneous operation of pumps, etc.

Turning to FIG. 2, a flowchart for implementing a method of operating control module 30 is illustrated. Sensor 36 determines whether the pump is on for a period of time controlled by clock 34; if the pump is not on, module 30 sets a first pass counter to yes. This continues until operation of the pump is sensed, at which time the module sets the first pass counter to no, initializes the down counter to a predetermined value, and encodes the first reference weight. . At each subsequent time interval, module 30 decrements the down counter by one unit until the down counter reaches zero.

When the down counter reaches zero, the next period is the second or current weight detection or line 2.
8 and module 30 compares it to a first reference weight. If the current weight is not greater than the reference weight, an alarm will be activated;
Indicates no flow condition. If the current weight is greater than the reference weight, the down counter is then reset, the current weight is set to the reference weight, and the cycle restarts.

Prior to resetting the down counter, the method may further include checking for low flow and high flow conditions in addition to or in place of no flow. This may be accomplished by comparing the weight change between the reference and current weights to a desired predetermined weight change. If the actual weight change is less than the preselected weight change, a low flow alarm is activated; if the actual weight change is greater than the preselected weight change, a high flow alarm is activated. Ru. With respect to the flowchart of FIG. 2, module 30 begins comparing the current weight to the sum of the reference weight plus the minimum expected weight increase within the time period. If the current weight is less than the total value, a low flow alarm will be activated; if the current weight is not less than the total value, the module will combine the current weight with the reference weight plus the maximum expected during the period. Start comparing with the total weight increase. If the current weight is greater than the sum, a high flow alarm is activated; if not, the down counter is reset and a reference weight is set equal to the current weight.

It has been found that in order to precisely monitor and transfer a predetermined amount of fluid from a supply vessel to a receiving vessel, the velocity of the fluid should be reduced for the last portion of the fluid being delivered. This reduced velocity allows more precise monitoring of fluid flow and therefore more accurate determination of the final weight in the receiving vessel 20. This is done by displacing the majority of the fluid to be transferred at a first high speed and the last part of the fluid being transferred at a second slow speed, preferably pulsed, to achieve the desired pre- This is achieved by accurately obtaining the selected weight. Of course, the operation of the present invention takes into account variations in pump speed and corresponding flow rate.

The device of the present invention directly detects the change in weight of the receiving container before and after a predetermined time interval, that is, the actual amount of fluid transferred, and monitors the operation of the device based on the weight change. It has superior accuracy and reproducibility compared to known monitoring devices that indirectly measure the amount of fluid transferred based on the flow rate of the fluid.

Modifications and variations of the present invention are possible in light of the above techniques. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.