JPS6253715A - Monitor for clogging of filter - Google Patents

Abstract

PURPOSE:To predict the state of clogging of a filter and its progress and to detect the clogging in its early stages, by providing a pressure detector for a filter differential pressure, a filter state prediction and arithmetic circuit and a filter state display device. CONSTITUTION:A filter differential pressure is detected by a pressure detector 7 through a pressure-detecting taps 6, 6 provided before and after a filter 3 and is inputted as a differential pressure signal into an arithmetic circuit 8 for predicting a filter state. Into the circuit 8 are also inputted an operational instruction signal from a pump operation state detecting circuit 9, a differential pressure setting signal from a differential pressure setting circuit 10. These input signals are inputted through an input interface 12 into a microprocessor 13 together with a sampling time setting signal from a sampling time setup circuit 16, for computing the residual time T for used of the filter 3. The operation result is inputted into a memory circuit 14 and a filter state display device 11, and, when T=0, an alarm signal is outputted from the filter state prediction and arithmetic circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a device that predicts the state of clogging of a filter in a filter device and its progress and monitors the state of the filter.

[Technical background of the invention and its problems]

2. Description of the Related Art In various industrial plants including nuclear power plants, filter devices have been conventionally used as a means for removing dust and dirt from process fluids flowing in piping or containers. If this filter device continues to operate,
Dirt and dirt accumulate in the filter in the filter device, causing it to become clogged, so operators inspect the condition of the filter through patrols, and when the filter reaches the condition specified in the usage standards, they replace it with a new filter. .

Alternatively, the filter is prevented from becoming clogged by cleaning or the like.

However, such patrols by operators place a considerable burden on the operators, and if a clogged filter is overlooked during the patrol, not only will the detection efficiency decrease, but the filter differential pressure and its The drawback was that component equipment such as pumps would break down, which would have a negative impact on the plant.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a clogging monitoring device for a filter device that can predict the state of filter clogging and its progress, and detect clogging of the filter at an early stage. It is in.

[Summary of the invention]

A clogging monitoring device according to the present invention includes a pressure detector that detects a filter differential pressure within a filter device, and a differential pressure signal outputted from this pressure detector that is input to detect the difference when the filter device is in an operating state. A filter condition prediction calculation circuit calculates the remaining usable time of the filter by calculating the time rate of change of the pressure signal, and the calculation results of this filter condition prediction calculation circuit are displayed and an alarm is issued when the filter reaches its usage limit. The present invention is characterized in that it is equipped with a filter status display device that emits a filter status display device.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a filter device and its clogging monitoring device. The filter device W1 sucks process fluid containing particulates such as dirt and dust from the suction port 2 with a pump 4, and It is configured to be discharged from a discharge port 5 through a filter 3. This filter device 1 is provided with pressure detection taps 6.6 before and after the filter 3 in order to detect the clogged state of the filter 3.

These pressure detection taps 6.6 are each connected to a pressure detector 7.
, and supplies the pressures on the upstream and downstream sides of the filter 3 to the pressure detector 7 as pressure signals.

The pressure detector 7 converts the pressure signal introduced from the pressure detection tap 6.6 into a differential pressure signal, and the converted differential pressure signal is supplied to the filter state prediction calculation circuit 8.

This filter state prediction calculation circuit 8 calculates the remaining usable time of the filter 3 from the output signal of the pressure detector 7. For example, as shown in FIG.
, a microprocessor 13, a memory circuit 14, an output interface 15, a sampling time setting circuit 16, and the like.

Further, 9 is a pump operating state detection circuit for detecting the operating state of the pump 4, and 10 is a differential pressure setting circuit for setting the usage limit differential pressure of the filter 3. The pump operation state detection circuit 9
is configured to output a computation request signal when it detects that the pump 4 is in an operating state, and the filter state prediction computation circuit 8 starts computation in response to an output signal from the pump operating state detection circuit 9. ing. In addition, 11
is a filter status display device that displays the calculation results of the filter status prediction calculation circuit 8, and is configured to issue an alarm by an alarm signal from the filter status prediction calculation circuit 8 when the filter 3 reaches its usage limit.

Next, the operation of this embodiment will be explained.

The filter 3 in the filter device 1 collects dirt and dust in the process fluid sucked from the suction port 2 by the pump 4 on the filter surface. As a result, particulates such as dirt and dust accumulate on the surface of the filter 3, and the accumulation of these particulates creates a pressure difference (hereinafter referred to as filter differential pressure) between the upstream side and the downstream side of the filter 3. This filter differential pressure is detected by the pressure detector 7 via pressure detection taps 6.6 provided before and after the filter 3, and is input to the filter state prediction calculation circuit 8 as a differential pressure signal. At this time, a calculation request signal is inputted to the filter state element '1s calculation circuit 8 from the pump operation state detection circuit 9, and the differential pressure setting circuit 1
A differential pressure setting signal is input from 0. The filter state prediction calculation circuit 8 inputs these input signals together with the sampling time setting signal from the sampling setting time circuit 16 to the microprocessor 13 via the input interface 12, and calculates the remaining usable time of the filter 3.

The calculation method will be explained below. When particulates such as dirt and dust accumulate in the filter 3, the clogged state of the filter 3 is generally expressed by the following equation.

P-f (Xr, X2, X3, X4,
Xs) Here, P is the state quantity of filter clogging, ×1
is the operating time of the pump, ×2 is the flow rate of the process fluid, ×3
is the particle diameter in the process fluid, x4 is the particle size in the process fluid, and X5 is the mesh size of the filter. This is how filter 3 is clogged! gIP is expressed as a function of five independent parameters, filter 3
It is difficult to accurately understand the growth process of clogging using equation (1). Therefore, it can be approximately determined by the method described below.

For example, as shown in FIG. 3, the filter differential pressure ΔP, which changes moment by moment, is sampled at a predetermined sampling time Δt, and the rate of change over time is calculated as shown in the following equation.

d(ΔP)/dt-ΔP/Δt (2+, where ΔP-ΔP++l-ΔP1, Δt-T++1+T+.

If the sampling time Δt is made smaller in the above equation, the growth rate of the clog, that is, the slope of the curve shown in Figure 3, can be calculated from equation (2), regardless of the five parameters x 1 to x 5 shown in equation (1). Then, the time rate of change (ΔP/Δ
t) and the usable limit differential pressure Δp set of the filter 3 set by the differential pressure setting circuit 10, the remaining usable time T of the filter 3 can be calculated by the following equation.

(ΔP/Δt) The above calculation is performed by the microprocessor 13 in the filter state prediction calculation circuit 8, and the calculation result is output to the storage circuit 14 and the filter state display device 112. As a result, the growth process of the clogging state of the filter 3 is recorded in the storage circuit 14, and the remaining usable time T of the filter 3 is displayed on the filter state display device 12. And T-
When the value becomes 0, an alarm signal is output from the filter condition prediction calculation circuit 8 to notify the operator that the filter 3 has reached the time to be replaced.

〔Effect of the invention〕

As described above, according to the present invention, the clogged state of the filter and its progress can be accurately predicted, so failures of the filter device and the pump can be prevented, and the burden on the operator can be significantly reduced.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a filter device and its clogging monitoring device, and FIG. 2 is a filter state prediction calculation circuit shown in FIG. 1. FIG. 3 is a miniature diagram showing temporal changes in filter differential pressure. DESCRIPTION OF SYMBOLS 1... Filter device, 3... Filter, 7... Pressure detector, 8... Filter state prediction calculation circuit, 11.
...Filter status display device. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] A pressure detector for detecting a filter differential pressure in a filter device, and a differential pressure signal outputted from this pressure detector are inputted, and the time rate of change of the differential pressure signal is calculated when the filter device is in an operating state. A filter state prediction calculation circuit that calculates the remaining usable time of the filter, and a filter state display device that displays the calculation results of the filter state prediction calculation circuit and issues an alarm when the filter reaches its usage limit. A clogging monitoring device for a filter device, characterized by: