JPH0295407A - Device for monitoring filter - Google Patents

Abstract

PURPOSE:To calculate the service life of filters by sampling groups of data on the negative pressures of the filters under suction with a controller at intervals of a certain time, calculating an mth-degree function for the filters from the mean values in the groups and comparing the function with the min. negative pressure of the filters under suction. CONSTITUTION:Groups of data on the negative pressures of n-filters 11 under suction are sampled with a controller 15 at intervals of a certain time, the max. and min. values are excluded and the mean values in the groups are obtd. An mth-degree function showing the change of the purifying performance of the filters 11 is calculated from the mean values and the service life of the filters is calculated by comparing the function with the min. negative pressure of the filters under suction. The accuracy of detected data is enhanced and the service life of the filters can be accurately calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a filter monitoring device for detecting the remaining life of a filter of a compressor or the like.

[Prior Art] In devices such as compressors that continuously supply working fluids such as air and gas to a plant, it is necessary to continuously supply clean fluid to the plant.

Conventionally, this problem has been dealt with by providing a filter upstream of the plant that does not create resistance to the fluid passing through it.

[Problems to be Solved by the Invention] In devices that are operated continuously, such as an L5 compressor, clogging of the filter is detected even during operation.

It is necessary to monitor the life of the filter and replace or replace the filter that has reached the end of its life in order to maintain operating performance above a certain level.

[Means for Solving the Problems] The second invention aims to solve the above problems, and this invention samples suction negative pressure data groups of n filters at fixed time intervals, and samples the maximum suction pressure data for each group.・A controller that calculates the average value by excluding the minimum value, calculates the m-th function that indicates the change in the cleaning performance of the filter from these average values, and calculates the life of the filter from the m-th function that is checked against the limit suction negative pressure of the filter. A filter monitoring device is constructed from the following.

[Function] The controller samples suction negative pressure data groups of n filters at regular intervals, removes the maximum and minimum values for each group, and calculates the average value. A function is determined, and the filter's limit suction negative pressure is compared with the determined m-th order function to calculate the life of the filter.

[Embodiment] A preferred embodiment of the present invention will be described below based on the accompanying drawings.

First, the installation of the suction filter monitoring device of the present invention will be taken as an example, and the schematic structure of a centrifugal compressor will be explained based on the flow sheet shown in FIG.

As shown in the figure, the centrifugal pressure ff1l is driven by an actuator (not shown) on the suction side of the centrifugal compressor all.
A guide vane 2 is provided to change the inflow angle of the suction air to the impeller of il to change the suction air flow rate of the centrifugal compression I11, and to change the pressure curve of the centrifugal pressure aaii.
An air discharge control valve 5 that prevents surging by returning a part of the compressed air to the suction side 4 of the centrifugal compression Ill downstream of the pressure fluid conveyance path 3 connected to the discharge part of the m machine 1 or releasing it to the atmosphere.
is provided. In this embodiment, the centrifugal compressor 1 is constructed by connecting three compression sections in series in the discharge direction, each of which sucks in air, compresses it, and then discharges it. It consists of a compressor casing (none of which is shown) that rotatably accommodates the compressor. However, the drive shafts (not shown) of the impellers are each connected to the gear 1 by a drive power transmission mechanism (not shown) such as a lane or a drive belt, and these drive shafts are connected to one drive motor 6.
The tops are arranged in such a way that they interlock with each other. The upstream side of the check valve 25 provided downstream from the third stage is configured so that it can be released to the atmosphere by the air discharge control valve 5, and the flow rate of the centrifugal pressure aii is adjusted by providing a guide vane 2 in front of the impeller on the first stage side. By configuring it so that it can do so, the centrifugal pressure MJR1 can be operated in a load/no-load mode. A suction filter 11 is provided on the suction side of the centrifugal compressor 1.

In the embodiment, the controller 15 is a CPU (central processing unit: hereinafter simply referred to as a CPU) as shown in FIG.
A, /D (analog, /digital signal: hereinafter referred to as A
, /D) converter 18 and (:', PIO (process input/output device 2 or below, referred to as PIO) 17 that inputs and outputs data between the PU 16 and the CPU 16 stores the operation of the centrifugal compressor 1. It is composed of a map 20.

The current value of the drive motor 6 is inputted to the A/D converter 18 via the current converter 19, and the current value of the drive motor 6 is inputted to the A/D converter 18 via the pressure converter 23.
The discharge pressure of the centrifugal compressor 1 is input. 28
is the receiver tanta.

In this embodiment, a pressure transducer 13 is installed downstream of the suction filter 11 as a detection means for detecting the suction negative pressure of the suction filter 11 as a change in voltage. The configuration is such that the detected voltage of the pressure detector 13 is input to the controller 15 through the A/D converter 18. On the other hand A/D
The converter 18 has a sampling period T of a set constant time.
The configuration is such that the detected voltage is sampled each time, sequentially quantized, and an encoded signal is input to the controller 15.

On the other hand, the CPU 16 is configured to execute the following control.

As shown in the flowchart of FIG. 1, the CPU 16 goes through a start 40 and first determines in a judgment 41 whether or not the blow-off control valve 5 is energized and closes, and the centrifugal compressor 1 is operating under load. If YES, the elapsed time of the load operation is integrated, and when a certain period of time has elapsed in judgment 42, a subroutine 44 is entered in counter 43. In this subroutine 44, first, in step 45, the output voltage PF+ of the pressure detector 13, the load operating time TH, and the current value A are sent to the CPU 16.
When the current value A exceeds the set current value of MIN・AMP that sets the lower limit load of the drive motor of the centrifugal compressor 1 in judgment 46, that is, when the load operation is continued, the difference read in step 47 The pressure PF is multiplied by a correction coefficient f1 based on MAX-AMP, which sets the upper limit load of the drive motor of the centrifugal compressor 1, to obtain the differential pressure DPE with respect to the load factor. In subroutine 44, ten differential pressures DPE are sampled. After exiting subroutine 44, CPU 16
In step 48, two maximum and minimum differential pressure DPEs are removed from the 10-piece data group to obtain the average value DPI of six intermediate values, and in judgment 49, this average value DPI and the tolerance of the above-mentioned suction filter 11 are determined. Limit suction negative pressure (e.g. 600 II
When the judgment of 0 judgment 49, which executes the comparison with IIAq), exceeds the permissible limit suction negative pressure, the CPU 16 outputs to a display means such as a display, and displays "Large suction filter pressure loss" (
Step 50) and "minor failure" (step 51) are executed.

Subroutine 50 samples five average DPI values. Then C, P U 16 goes to step 5
9 Judgment 5: Remove the maximum and minimum two values from the average value DPI sampled in step 2 to obtain the average value DP of the three intermediate values.
3, after resetting, it is determined whether or not the previous average value DP is stored; if NO, this DP is set as DPS; 1, in determination 54, it is determined that DP<DPI+f2, that is, the latest average value DP is the value after replacing the filter and resetting DPS
If the relationship exceeds the value obtained by adding f2 to
In step 56, preventive maintenance call is displayed, and in step 56, intake filter maintenance is displayed. In step 57, the sampling time of the data up to now is set as Tn, and the process proceeds to step 58, where the average value DP is sequentially input into a FIFO (first-in, first-out) memory as an encoded signal, and in step 59, the sampling time Tn is set as The signals are sequentially input to the FIFO memory as encoded signals. Thereafter, the CPU 18 checks in step 17i60 whether the number of samples of the average value DP is three (1), and in the next judgment 61 judges whether the DPI is increasing. That is, when the relationship of DPI < DP2 < DP3 holds, the life function ΔP=
Perform calculations to obtain AT2+BT+C (see Figure 3),
Then, in step 66, the filter life TL is calculated. In the example shown in Figure 1, the time required for the differential pressure across the filter to reach 600111AQ is calculated.

Then, in step 67, the remaining life time TR is obtained by subtracting the elapsed time from the life time TL to the latest sampling time T3. At step 70, the amount of time TR remaining in the suction filter 11 is displayed.

As described above, since the remaining life of the suction filter 11 can be detected and displayed with high precision, the suction filter 11 can be quickly cleaned and replaced. Although the explanation is applied to filters, the application is not limited to centrifugal compressor suction filters, and the fluid used is not limited to air.Also, the life function is not limited to quadratic, but can be a linear or higher order function. .

[Effects of the Invention] As is clear from the above explanation, the present invention exhibits the following excellent effects.

Sample the suction negative pressure data groups of n filters at regular intervals, remove the maximum and minimum values for each group, and find the average value, and from these average values, find the m-th order function that indicates the cleaning performance of the filter. Since the suction filter monitoring device is configured with a controller that calculates the filter life from an m-order function that is checked against the limit suction negative pressure of the filter, it is possible to improve the accuracy of detection data and obtain accurate filter life time. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing a preferred embodiment of the present invention;
FIG. 2 is a schematic diagram of a centrifugal compressor according to the present invention, and FIG. 3 is a schematic diagram showing the relationship between sampling data of suction negative pressure with respect to filter time and m-th order remaining life performance of the filter. 11 is a suction filter, and 15 is a controller. Patent applicant Nobuo Kinuya, patent attorney representing Ishikawajima-Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1. Sample the suction negative pressure data groups of n filters at regular intervals, and calculate the average value excluding the maximum and minimum values for each group, and use these average values to show the change in the cleaning performance of the filter. A filter monitoring device comprising: a controller that calculates the life of the filter from the m-th function, which calculates the m-th function and compares it with the filter's limit suction negative pressure.