JP2013164024A - System for controlling number of compressors - Google Patents

System for controlling number of compressors Download PDF

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JP2013164024A
JP2013164024A JP2012027622A JP2012027622A JP2013164024A JP 2013164024 A JP2013164024 A JP 2013164024A JP 2012027622 A JP2012027622 A JP 2012027622A JP 2012027622 A JP2012027622 A JP 2012027622A JP 2013164024 A JP2013164024 A JP 2013164024A
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pressure
compressor
compressors
limit pressure
lower limit
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JP5915931B2 (en
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Shigeki Ochi
重喜 越智
Yoshihiro Sagawa
良浩 寒川
Yusuke Okamoto
裕介 岡本
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Miura Co Ltd
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Miura Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a system for controlling the number of compressors, capable of producing a compressed air in a manner quickly following a use load of the compressed air with a simple structure.SOLUTION: An operating number controller 5 changes the number of operating compressors 2 on the basis of a detection pressure of a pressure sensor 4. Each compressor 2 is subjected to capacity control between an upper limit pressure and a lower limit pressure so that a discharge pressure is maintained between the upper limit pressure and the lower limit pressure, wherein a load rate is 0% at the upper limit pressure or more and the load rate is 100% at the lower limit pressure or less. For each operating compressor, the load rate of each compressor 2 is determined on the basis of the detection pressure of the pressure sensor 4, a discharged air amount from each compressor 2 at the load rate is determined, and a total discharged air amount from the entire operating compressors is thereby determined. When the total discharged air amount is equal to or less than the total sum of the discharge capacities of other operating compressors excepting the next stop scheduled compressor, the next stop scheduled compressor is stopped.

Description

本発明は、複数台の空気圧縮機を備え、圧縮空気の使用負荷に応じて圧縮機の運転台数を変更する圧縮機台数制御システムに関するものである。   The present invention relates to a compressor number control system that includes a plurality of air compressors and changes the number of operating compressors according to the use load of compressed air.

従来、下記特許文献1に開示されるように、圧力とその変化率とに基づき、圧縮機の運転台数を増減する圧力閾値を変更することが提案されている。この特許文献1に記載の発明では、すべての圧縮機がオンオフ制御される(段落番号0029など)。   Conventionally, as disclosed in the following Patent Document 1, it has been proposed to change a pressure threshold value for increasing or decreasing the number of operating compressors based on a pressure and a rate of change thereof. In the invention described in Patent Document 1, all the compressors are on / off controlled (paragraph number 0029 and the like).

特開2007−120497号公報(特許請求の範囲、段落番号0140−0155、図15、図16)JP 2007-120497 A (claims, paragraph numbers 0140-0155, FIGS. 15 and 16)

しかしながら、圧力変化率は考慮されても、運転中の圧縮機の台数は考慮されていない。また、複数台の圧縮機は、単にオンオフ制御されている。これでは、圧縮空気の使用負荷に迅速に追従させて圧縮空気を製造することができない。   However, even if the pressure change rate is considered, the number of compressors in operation is not considered. In addition, the plurality of compressors are simply on / off controlled. In this case, the compressed air cannot be manufactured by quickly following the usage load of the compressed air.

本発明が解決しようとする課題は、簡易な構成で運転台数を考慮して制御し、圧縮空気の使用負荷に迅速に追従させて圧縮空気を製造することのできる圧縮機台数制御システムを提供することにある。   The problem to be solved by the present invention is to provide a compressor number control system capable of producing compressed air by controlling the number of operating units with a simple configuration and quickly following the usage load of the compressed air. There is.

本発明は、前記課題を解決するためになされたもので、請求項1に記載の発明は、複数台の圧縮機と、これら圧縮機から圧縮空気が供給されると共に圧縮空気利用機器へ圧縮空気を送る箇所に設けられ、圧縮空気の圧力を検出する圧力センサと、この圧力センサの検出圧力に基づき前記圧縮機の運転台数を変更する台数制御器とを備え、前記台数制御器により運転台数を減少させるか否かの境界値としての台数減少用圧力は運転台数が多いほど低くなる圧縮機台数制御システムであって、前記複数台の圧縮機として、吐出容量の異なる圧縮機が含まれ、前記各圧縮機は、吐出圧力を上限圧力と下限圧力との間に維持するように、その間で容量制御されると共に、上限圧力以上で負荷率0%、下限圧力以下で負荷率100%とされ、運転中の圧縮機について、前記圧力センサの検出圧力に基づき各圧縮機の負荷率を求めると共に、この負荷率における各圧縮機からの吐出空気量を求めて、これにより運転中のすべての圧縮機からの総吐出空気量を求め、この総吐出空気量が、次停止予定機を除く他の運転中の圧縮機の吐出容量の合計以下であれば、次停止予定機を停止させることを特徴とする圧縮機台数制御システムである。   The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is directed to a plurality of compressors, compressed air supplied from these compressors, and compressed air to a device using compressed air. A pressure sensor for detecting the pressure of compressed air, and a unit controller for changing the number of operating compressors based on the detected pressure of the pressure sensor. The number reduction pressure as a boundary value of whether or not to decrease is a compressor number control system that decreases as the number of operating units increases, and the compressors of different discharge capacities are included as the plurality of compressors, Each compressor is capacity-controlled between the upper limit pressure and the lower limit pressure so that the discharge pressure is maintained between the upper limit pressure and the lower limit pressure, the load factor is 0% above the upper limit pressure, and the load factor is 100% below the lower limit pressure. Pressure during operation For each compressor, the load factor of each compressor is determined based on the pressure detected by the pressure sensor, and the amount of air discharged from each compressor at this load factor is determined, whereby the total discharge from all operating compressors is obtained. The number of compressors characterized by determining the amount of air and stopping the next scheduled stop if the total amount of discharged air is less than or equal to the total discharge capacity of the compressors in operation other than the next scheduled stop Control system.

請求項1に記載の発明によれば、運転台数を減少させるか否かの境界値としての台数減少用圧力は、運転台数が多いほど低くなる。圧縮機の運転台数が多いほど、目標圧力に維持するための1台当たりの寄与率は下がり、圧力変動は抑えられるからである。
そして、吐出容量の異なる圧縮機が含まれる場合でも、圧力センサの検出圧力に基づき各圧縮機の負荷率ひいては吐出空気量を把握し、運転中のすべての圧縮機からの総吐出空気量が、次停止予定機を除く他の運転中の圧縮機の吐出容量の合計以下であれば、次停止予定機を停止させることで、必要最小限の台数で運転することができる。
According to the first aspect of the present invention, the number-decreasing pressure as a boundary value for determining whether or not to decrease the number of operating units decreases as the number of operating units increases. This is because as the number of operating compressors increases, the contribution rate per unit for maintaining the target pressure decreases, and the pressure fluctuation can be suppressed.
And even when compressors with different discharge capacities are included, the load factor of each compressor and the discharge air amount are grasped based on the detected pressure of the pressure sensor, and the total discharge air amount from all the compressors in operation is If it is less than the total discharge capacity of the compressors in operation other than the next scheduled stop machine, it is possible to operate with the minimum necessary number by stopping the next scheduled stop machine.

請求項2に記載の発明は、前記圧縮機は、優先機グループと非優先機グループとに分けられており、前記台数制御器は、運転台数を増加させる場合、優先機グループに属する圧縮機を、非優先機グループに属する圧縮機よりも優先して起動し、前記台数制御器は、運転台数を減少させる場合、非優先機グループに属する圧縮機を、優先機グループに属する圧縮機よりも優先して停止することを特徴とする請求項1に記載の圧縮機台数制御システムである。   The invention according to claim 2, wherein the compressor is divided into a priority machine group and a non-priority machine group, and when the number of operating units increases, the number controller controls a compressor belonging to the priority machine group. When the number of operating units is reduced, the unit controller prioritizes the compressor belonging to the non-priority machine group over the compressor belonging to the priority machine group. The compressor number control system according to claim 1, wherein the system is stopped.

請求項2に記載の発明によれば、優先機グループに属する圧縮機の運転を優先することで、たとえば省エネ性の高い圧縮機の運転を優先することができる。   According to the second aspect of the present invention, priority can be given to the operation of a compressor with high energy saving performance, for example, by giving priority to the operation of the compressor belonging to the priority machine group.

請求項3に記載の発明は、圧縮機として、インバータにより回転数を制御されるインバータ機を備えると共に、これ以外は、容量調整弁により上限圧力と下限圧力との範囲で容量制御される吸込絞り機とされ、前記インバータ機は、最も優先して運転されるように、前記優先機グループとして前記台数制御器に設定されており、前記吸込絞り機は、その吐出圧力を、下限圧力と上限圧力との間に維持するように容量制御され、前記インバータ機は、その吐出圧力を、次式による設定圧力に維持するようにインバータ制御されることを特徴とする請求項2に記載の圧縮機台数制御システムである。
インバータ機の設定圧力=下限圧力±{(上限圧力−下限圧力)×0.1}
The invention according to claim 3 is provided with an inverter machine whose rotation speed is controlled by an inverter as a compressor, and other than this, a suction throttle whose capacity is controlled in a range between an upper limit pressure and a lower limit pressure by a capacity adjustment valve The inverter unit is set in the number controller as the priority unit group so that the inverter unit is operated with the highest priority, and the suction throttle unit sets the discharge pressure to the lower limit pressure and the upper limit pressure. 3. The number of compressors according to claim 2, wherein the capacity is controlled so as to be maintained between and the inverter is controlled so as to maintain the discharge pressure at a set pressure according to the following equation: Control system.
Inverter set pressure = lower limit pressure ± {(upper limit pressure-lower limit pressure) x 0.1}

請求項3に記載の発明によれば、インバータ機の設定圧力を吸込絞り機の下限圧力近辺に設定することで、通常、インバータ機の設定圧力は、前記台数減少用圧力よりも低くなる。これにより、圧力変動の吸収をインバータ機に優先して行わせることができる。   According to the invention described in claim 3, the set pressure of the inverter machine is usually lower than the pressure for reducing the number of units by setting the set pressure of the inverter machine in the vicinity of the lower limit pressure of the suction throttle machine. Thereby, absorption of a pressure fluctuation can be made to give priority to an inverter machine.

さらに、請求項4に記載の発明は、前記圧力センサによる検出圧力以外に、前記圧縮機の冷却系統、および/または、前記圧縮機の電気系統、および/または、前記圧縮機からの圧縮空気の利用系統の状況にも基づき、前記圧縮機の運転台数を変更することを特徴とする請求項1〜3のいずれか1項に記載の圧縮機台数制御システムである。   Furthermore, in the invention according to claim 4, in addition to the pressure detected by the pressure sensor, the cooling system of the compressor and / or the electric system of the compressor and / or the compressed air from the compressor The compressor number control system according to any one of claims 1 to 3, wherein the number of operating compressors is changed based on the status of the utilization system.

請求項4に記載の発明によれば、圧縮機の冷却系統、電気系統、および圧縮機からの圧縮空気の利用系統の内、いずれか一以上の状況にも基づき制御することができる。これにより、圧縮機の異常や、急な負荷変動などにも迅速に対応することができる。   According to invention of Claim 4, it can control based also on any one or more situations among the cooling system of a compressor, an electric system, and the utilization system of the compressed air from a compressor. As a result, it is possible to quickly cope with a compressor abnormality or a sudden load fluctuation.

本発明によれば、簡易な構成で運転台数を考慮して制御し、圧縮空気の使用負荷に迅速に追従させて圧縮空気を製造することができる。   According to the present invention, it is possible to manufacture compressed air by controlling in consideration of the number of operating units with a simple configuration and quickly following the usage load of the compressed air.

本発明の圧縮機台数制御システムの一実施例を示す概略図である。It is the schematic which shows one Example of the compressor number control system of this invention. 図1の圧縮機台数制御システムによる台数制御方法の一例を示す図であり、運転中の各圧縮機の吐出圧力、レシーバタンク内の圧力、運転台数増減表を示している。It is a figure which shows an example of the number control method by the compressor number control system of FIG. 1, and has shown the discharge pressure of each compressor during a driving | operation, the pressure in a receiver tank, and a driving | operation number increase / decrease table.

以下、本発明の具体的実施例を図面に基づいて詳細に説明する。
図1は、本発明の圧縮機台数制御システムの一実施例を示す概略図である。本実施例の圧縮機台数制御システム1は、複数台の圧縮機2,2,…と、これら圧縮機2から圧縮空気が供給されるレシーバタンク3と、このレシーバタンク3内の圧力を検出する圧力センサ4と、この圧力センサ4の検出圧力などに基づき前記各圧縮機2を制御する台数制御器5とを備える。
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of a compressor number control system according to the present invention. The compressor number control system 1 according to the present embodiment detects a plurality of compressors 2, 2,..., A receiver tank 3 to which compressed air is supplied from the compressor 2, and a pressure in the receiver tank 3. A pressure sensor 4 and a number controller 5 for controlling the compressors 2 based on the pressure detected by the pressure sensor 4 are provided.

各圧縮機2は、典型的には電動式の空気圧縮機であり、圧縮機本体がモータで駆動され、外気を吸入し圧縮して吐出する。各圧縮機2からの圧縮空気は、共通のレシーバタンク3を介して、一または複数の各種の圧縮空気利用機器(図示省略)へ送られる。   Each compressor 2 is typically an electric air compressor, and the compressor body is driven by a motor to suck in, compress, and discharge outside air. Compressed air from each compressor 2 is sent to one or a plurality of various compressed air utilization devices (not shown) via a common receiver tank 3.

各圧縮機2は、スクリュー式、ターボ式またはレシプロ式など、その構成を特に問わないが、典型的には互いに同一の構成とされる。また、各圧縮機2は、典型的には、同一の吐出容量とされるが、後述するように、異なる吐出容量にも対応可能である。   Each compressor 2 is not particularly limited in its configuration, such as a screw type, a turbo type, or a reciprocating type, but typically has the same configuration as each other. Each compressor 2 typically has the same discharge capacity, but can also handle different discharge capacities as will be described later.

本実施例の各圧縮機2は、容量制御可能に構成される。ここでは、機械的に自力で容量制御可能とされる。容量制御の具体的構成は特に問わないが、本実施例では、圧縮機2の吸込側に設けた容量調整弁(図示省略)の開度を調整することでなされる。   Each compressor 2 of a present Example is comprised so that capacity | capacitance control is possible. Here, the capacity can be controlled mechanically by itself. Although the specific configuration of the capacity control is not particularly limited, in this embodiment, the capacity control is performed by adjusting the opening of a capacity adjustment valve (not shown) provided on the suction side of the compressor 2.

容量調整弁は、圧縮機2の吐出側の圧力を所望に維持するように、自力で開度を調整する。つまり、圧縮機2の吐出側の圧力が上昇するのに伴い、容量調整弁は開度を絞って吸入量を減少させ、これにより圧縮機2は吐出量を減少させる一方、圧縮機2の吐出側の圧力が低下するのに伴い、容量調整弁は開度を拡げて吸入量を増加させ、これにより圧縮機2は吐出量を増加させる。   A capacity | capacitance adjustment valve adjusts an opening degree by itself so that the pressure of the discharge side of the compressor 2 may be maintained as desired. In other words, as the pressure on the discharge side of the compressor 2 increases, the capacity adjustment valve reduces the suction amount by reducing the opening, thereby reducing the discharge amount while the compressor 2 reduces the discharge amount. As the pressure on the side decreases, the capacity adjustment valve increases the opening to increase the intake amount, thereby causing the compressor 2 to increase the discharge amount.

より具体的には、容量調整弁は、図2において、圧縮機2の吐出側の圧力を、下限圧力PLと上限圧力PHとの間に維持するように開度を調整する。この場合、容量調整弁は、圧縮機2の吐出側の圧力が下限圧力PL以下になると全開される一方、上限圧力PH以上になると全閉される。また、下限圧力PLと上限圧力PHとの間では、下限圧力PLから上限圧力PHへ行くに従って比例的に開度が絞られる。このように、下限圧力PLと上限圧力PHとの圧力範囲が、容量調整弁の制御範囲とされる。つまり、各圧縮機2は、容量調整弁により、規定の調整範囲PL〜PHで、吐出圧力と吐出流量とが逆比例のリニアな特性を有する。言い換えれば、吐出圧力と圧縮機2の負荷率とは一次関数になっている。なお、万一、圧縮機2の吐出側の圧力が所定の停止圧力PSを超えると、圧縮機2は強制停止される。   More specifically, in FIG. 2, the capacity adjustment valve adjusts the opening so as to maintain the pressure on the discharge side of the compressor 2 between the lower limit pressure PL and the upper limit pressure PH. In this case, the capacity adjustment valve is fully opened when the pressure on the discharge side of the compressor 2 is lower than the lower limit pressure PL, and is fully closed when the pressure is higher than the upper limit pressure PH. Further, the opening degree is proportionally reduced between the lower limit pressure PL and the upper limit pressure PH as it goes from the lower limit pressure PL to the upper limit pressure PH. Thus, the pressure range between the lower limit pressure PL and the upper limit pressure PH is the control range of the capacity adjustment valve. That is, each compressor 2 has a linear characteristic in which the discharge pressure and the discharge flow rate are inversely proportional to each other within a specified adjustment range PL to PH by the capacity adjustment valve. In other words, the discharge pressure and the load factor of the compressor 2 are linear functions. If the pressure on the discharge side of the compressor 2 exceeds a predetermined stop pressure PS, the compressor 2 is forcibly stopped.

本実施例の各圧縮機2は、典型的には、同時に複数台が運転される場合でもすべてが容量制御される。そのため、各圧縮機2は、全負荷運転に保持するためのフルロードロック機能を備える必要はない。   Each compressor 2 of the present embodiment is typically capacity-controlled even when a plurality of compressors 2 are operated at the same time. Therefore, it is not necessary for each compressor 2 to have a full load lock function for maintaining full load operation.

レシーバタンク3は、各圧縮機2から圧縮空気が供給される一方、一または複数の圧縮空気利用機器へ圧縮空気を供給する中空容器である。レシーバタンク3内の圧力を検出可能に、圧力センサ4が設けられる。   The receiver tank 3 is a hollow container that is supplied with compressed air from each compressor 2 and supplies compressed air to one or a plurality of compressed air using devices. A pressure sensor 4 is provided so that the pressure in the receiver tank 3 can be detected.

台数制御器5は、各圧縮機2および圧力センサ4に接続され、圧力センサ4による検出圧力などに基づき、各圧縮機2を制御する。本実施例では、各圧縮機2の運転の有無(つまり運転台数の変更)を切り替える。具体的な制御方法は、以下のとおりである。   The number controller 5 is connected to each compressor 2 and the pressure sensor 4, and controls each compressor 2 based on the pressure detected by the pressure sensor 4. In this embodiment, the presence or absence of operation of each compressor 2 (that is, change of the number of operating units) is switched. A specific control method is as follows.

図2は、本実施例の圧縮機台数制御システム1による台数制御方法の一例を示す図であり、運転中の各圧縮機2の吐出圧力と、レシーバタンク3内の圧力(つまり圧力センサ4の検出圧力)と、運転台数増減表とを示している。   FIG. 2 is a diagram showing an example of the number control method by the compressor number control system 1 of the present embodiment. The discharge pressure of each compressor 2 during operation and the pressure in the receiver tank 3 (that is, the pressure sensor 4) Detection pressure) and the number of operating units increase and decrease table.

運転台数増減表は、図2の中央に表形式で示すように、運転台数を増やすための起動表と、図2の右側に棒グラフ状に示すように、運転台数を減らすための停止表とに分けられる。起動表は、レシーバタンク3内の圧力Pとその変化率ΔPとに基づき、圧縮機2を如何に起動するか、言い換えれば運転台数を如何に増加させるかを示している。一方、停止表は、レシーバタンク3内の圧力Pと、現在実際に運転中の台数とに基づき、圧縮機2を如何に停止するか、言い換えれば運転台数を如何に減少させるかを示している。これらの制御は、圧力センサ4の検出圧力Pと圧力変化率ΔPとをそれぞれ所定周期で求め、それに基づき行われる。本実施例では、検出圧力Pとして、台数制御器5のCPUの演算周期の所定回数分(たとえば20回分)の平均値が用いられ、圧力変化率ΔPとして、直近の所定時間(たとえば直近20秒)の平均値が用いられる。   As shown in the form of a table in the center of FIG. 2, the operation number increase / decrease table is divided into a start table for increasing the operation number and a stop table for reducing the operation number as shown in a bar graph on the right side of FIG. Divided. The start-up table shows how to start the compressor 2 based on the pressure P in the receiver tank 3 and the rate of change ΔP, in other words, how to increase the number of operating units. On the other hand, the stop table shows how to stop the compressor 2 on the basis of the pressure P in the receiver tank 3 and the number of units currently in operation, in other words, how to reduce the number of units in operation. . These controls are performed based on the detected pressure P of the pressure sensor 4 and the pressure change rate ΔP at predetermined intervals. In the present embodiment, an average value for a predetermined number of times (for example, 20 times) of the calculation cycle of the CPU of the number controller 5 is used as the detected pressure P, and the most recent predetermined time (for example, the latest 20 seconds) is used as the pressure change rate ΔP. ) Average value is used.

圧力変化率ΔPとは、所定時間当たりの変動圧力である。圧力変化率ΔPがマイナスの場合、レシーバタンク3内の圧力は減少傾向にあり、圧力変化率ΔPがプラスの場合、レシーバタンク3内の圧力は増加傾向にある。圧縮空気利用機器による圧縮空気の使用量が、圧縮機2による圧縮空気の吐出量よりも多い場合、レシーバタンク3内の圧力は減少し、逆に、圧縮機2による圧縮空気の吐出量が、圧縮空気利用機器による圧縮空気の使用量よりも多い場合、レシーバタンク3内の圧力は増加する。   The pressure change rate ΔP is a fluctuating pressure per predetermined time. When the pressure change rate ΔP is negative, the pressure in the receiver tank 3 tends to decrease, and when the pressure change rate ΔP is positive, the pressure in the receiver tank 3 tends to increase. When the amount of compressed air used by the device using compressed air is larger than the amount of compressed air discharged by the compressor 2, the pressure in the receiver tank 3 decreases, and conversely, the amount of compressed air discharged by the compressor 2 is When the amount of compressed air used is greater than the amount of compressed air used by the device using compressed air, the pressure in the receiver tank 3 increases.

圧縮機2からレシーバタンク3への配管の圧力損失により、レシーバタンク3内の圧力は、圧縮機2の吐出圧力よりも若干低圧になる。そのため、図2において若干傾きのある破線で結んで示すように、レシーバタンク3内の圧力PL1,PL2は、それぞれ、圧縮機2の吐出圧力PL1´,PL2´と対応する。なお、本実施例の圧縮機台数制御システム1の場合、停止表から明らかなとおり、レシーバタンク3内の圧力が容量調整弁の制御範囲の上限圧力PHになるときは、すべての圧縮機2が停止され、空気流量は0になるので、上限圧力PHに関しては、圧縮機吐出圧力とレシーバタンク圧力とは同一になる。   Due to the pressure loss of the piping from the compressor 2 to the receiver tank 3, the pressure in the receiver tank 3 is slightly lower than the discharge pressure of the compressor 2. Therefore, the pressures PL1 and PL2 in the receiver tank 3 correspond to the discharge pressures PL1 ′ and PL2 ′ of the compressor 2, respectively, as shown by a broken line having a slight inclination in FIG. In the case of the compressor number control system 1 of this embodiment, as is apparent from the stop table, when the pressure in the receiver tank 3 becomes the upper limit pressure PH of the control range of the capacity adjustment valve, all the compressors 2 are Since the air flow rate is stopped, the compressor discharge pressure and the receiver tank pressure are the same with respect to the upper limit pressure PH.

台数制御器5は、圧力センサ4の検出圧力と、予め設定した圧力値とを比較して、圧縮機2の運転台数を増減する。この際、運転台数を増加させる圧力値は、前記起動表に示すように、圧力センサ4の検出圧力Pの圧力変化率ΔPに基づき異なるよう設定される。つまり、台数制御器5は、圧力センサ4の検出圧力Pが台数増加用圧力A以下になると圧縮機2を1台起動させるが、運転台数を増加させるか否かの境界値としての台数増加用圧力Aは、圧力変化率ΔPがマイナス側へ大きくなるほど段階的に高圧になるよう設定される。   The number controller 5 compares the detected pressure of the pressure sensor 4 with a preset pressure value, and increases or decreases the number of operating compressors 2. At this time, the pressure value for increasing the number of operating units is set to be different based on the pressure change rate ΔP of the detected pressure P of the pressure sensor 4 as shown in the startup table. In other words, the number controller 5 starts one compressor 2 when the detected pressure P of the pressure sensor 4 is equal to or less than the number-increasing pressure A, but increases the number as a boundary value of whether to increase the number of operating units. The pressure A is set so as to increase gradually as the pressure change rate ΔP increases to the negative side.

運転台数を増加させる場合、台数制御器5は、圧力センサ4の検出圧力Pが台数増加用圧力A以下の状態を維持する場合、所定時間(連続起動防止時間)を経過するごとに前記圧縮機2を1台起動させるが、圧力変化率ΔPが設定値(−ΔP1)以下の領域(つまりΔP≦−ΔP1)では、圧力センサ4の検出圧力Pが即時増加用圧力B以下になれば、前記所定時間の経過を待つことなくさらに1台起動させる。なお、即時増加用圧力Bは、圧力変化率ΔPの絶対値が大きいほど高圧に設定されるのがよい。   When the number of operating units is to be increased, the unit controller 5 is configured such that, when the detected pressure P of the pressure sensor 4 is maintained at a level equal to or lower than the number increasing pressure A, the compressor 2 is started, but in a region where the pressure change rate ΔP is equal to or less than the set value (−ΔP1) (that is, ΔP ≦ −ΔP1), if the detected pressure P of the pressure sensor 4 is equal to or less than the immediate increase pressure B, One more unit is activated without waiting for the elapse of a predetermined time. The immediate increase pressure B is preferably set to a higher pressure as the absolute value of the pressure change rate ΔP is larger.

一方、運転台数を減少させる圧力値は、前記停止表に示すように、現在実際に運転中の圧縮機2の運転台数に基づき異なるよう設定される。つまり、台数制御器5は、圧力センサ4の検出圧力Pが台数減少用圧力C以上になると圧縮機2を1台停止させるが、運転台数を減少させるか否かの境界値としての台数減少用圧力Cは、運転台数が増すほど段階的に低圧になるよう設定される。   On the other hand, as shown in the stop table, the pressure value for decreasing the number of operating units is set to be different based on the number of operating compressors 2 that are currently operating. That is, the number controller 5 stops one compressor 2 when the detected pressure P of the pressure sensor 4 is equal to or higher than the number reduction pressure C, but the number controller 5 serves as a boundary value for determining whether or not to reduce the number of operating units. The pressure C is set so as to gradually decrease as the number of operating units increases.

台数減少用圧力Cは、各圧縮機2の負荷率を考慮して決定するのがよい。すなわち、停止時(上限圧力PH以上)を負荷率0%、全負荷時(下限圧力PL以下)を負荷率100%とした場合に、運転中の圧縮機2の1台当たりの負荷率が次式により求められる停止負荷率以下になると、運転中の1台を停止させる。   The pressure C for reducing the number of units should be determined in consideration of the load factor of each compressor 2. That is, when the load factor is 0% when stopped (above the upper limit pressure PH) and the load factor is 100% when full load (lower limit pressure PL or less), the load factor per compressor 2 in operation is If it becomes below the stop load factor calculated | required by a type | formula, one in operation will be stopped.

[数1] 停止負荷率(%)=(運転台数−1)/運転台数×100   [Equation 1] Stop load factor (%) = (Number of operating units-1) / Number of operating units × 100

台数制御器5は、運転中の台数に応じた停止負荷率で1台を停止させるために、運転中の台数に基づき台数減少用圧力Cを次式により求め、これに基づき運転台数を適宜減少させる。   The number controller 5 calculates the pressure C for reducing the number of units based on the number of units in operation by the following formula in order to stop one unit at a stop load factor according to the number of units in operation, and reduces the number of units operated accordingly based on this formula. Let

[数2] 台数減少用圧力C=上限圧力PH−{(上限圧力PH−下限圧力PL)×停止負荷率(%)/100}   [Equation 2] Number of pressure reduction C = upper limit pressure PH − {(upper limit pressure PH−lower limit pressure PL) × stop load factor (%) / 100}

この数式2は、前記数式1を用いて、次のように書き換えることができる。   This Formula 2 can be rewritten as follows using the Formula 1.

[数3] 台数減少用圧力C={(上限圧力PH−下限圧力PL)/運転台数}+下限圧力PL   [Equation 3] Number of units decreasing pressure C = {(upper limit pressure PH−lower limit pressure PL) / number of operating units} + lower limit pressure PL

このように、運転台数に応じて台数減少用圧力Cを規定することができる。なお、数式2および数式3にいう上限圧力PHおよび下限圧力PLは、前述したように容量調整弁の制御範囲を規定する圧縮機吐出圧力であるが、実際の停止制御は本実施例ではレシーバタンク3に設けた圧力センサ4の検出圧力に基づきなされるので、圧縮機2とレシーバタンク3との間の圧力損失を考慮して補正した値を用いるのが好ましい。但し、上限圧力PHについては、前述したように、圧縮機吐出圧力とレシーバタンク圧力とは同一になる。従って、下限圧力PLについて、レシーバタンク圧力に換算した値を用いるのが好ましい。あるいは、数式2および数式3で導出される台数減少用圧力Cは厳密には圧縮機吐出圧力であるので、これをレシーバタンク圧力に換算して制御するのが好ましい。   In this way, the pressure C for decreasing the number can be defined according to the number of operating units. Note that the upper limit pressure PH and the lower limit pressure PL in the formulas 2 and 3 are compressor discharge pressures that define the control range of the capacity adjustment valve as described above, but the actual stop control is performed in the receiver tank in this embodiment. 3 is performed based on the detected pressure of the pressure sensor 4 provided in 3, it is preferable to use a value corrected in consideration of the pressure loss between the compressor 2 and the receiver tank 3. However, as described above, the upper limit pressure PH is the same as the compressor discharge pressure and the receiver tank pressure. Therefore, it is preferable to use the value converted into the receiver tank pressure for the lower limit pressure PL. Alternatively, the number-decreasing pressure C derived from Equation 2 and Equation 3 is strictly a compressor discharge pressure, and is preferably controlled by converting it into a receiver tank pressure.

以下、具体的制御について、図2に基づき説明する。なお、第一下限圧力PL1よりも低圧で第二下限圧力PL2が設定され、第一下限圧力PL1および第二下限圧力PL2は、容量調整弁の制御範囲下限値PLよりも低圧に設定される。また、第一設定値ΔP1,第二設定値ΔP2は、圧縮機1台分の全負荷運転時の吐出容量を考慮して設定される。   Hereinafter, specific control will be described with reference to FIG. The second lower limit pressure PL2 is set lower than the first lower limit pressure PL1, and the first lower limit pressure PL1 and the second lower limit pressure PL2 are set lower than the control range lower limit PL of the capacity adjustment valve. The first set value ΔP1 and the second set value ΔP2 are set in consideration of the discharge capacity during full load operation for one compressor.

(1)圧縮機2の運転台数の増加制御
(1−1)圧力変化率ΔPの絶対値が第一設定値ΔP1未満である場合。具体的には、−ΔP1<ΔP<+ΔP1である場合。
圧力センサ4の検出圧力Pが台数増加用圧力Aとしての第二下限圧力PL2以下になると1台起動させる。これにより通常は圧力が第二下限圧力PL2を上回るが、この間も圧縮空気の使用負荷が増加し続けると、圧力が第二下限圧力PL2以下を維持する場合がある。その場合、所定の連続起動防止時間を経過するごとに圧縮機2を1台起動させる。つまり、圧力センサ4の検出圧力Pが図2における「1台起動」領域に留まる場合には、停止中の圧縮機2がある限り、連続起動防止時間を経過するごとに1台ずつ起動させる。
(1) Increase control of the number of operating units of the compressor 2 (1-1) When the absolute value of the pressure change rate ΔP is less than the first set value ΔP1. Specifically, when -ΔP1 <ΔP <+ ΔP1.
When the detected pressure P of the pressure sensor 4 is equal to or lower than the second lower limit pressure PL2 as the pressure A for increasing the number of units, one unit is activated. As a result, the pressure normally exceeds the second lower limit pressure PL2, but if the use load of compressed air continues to increase during this time, the pressure may remain below the second lower limit pressure PL2. In that case, every time the predetermined continuous activation prevention time elapses, one compressor 2 is activated. That is, when the detected pressure P of the pressure sensor 4 remains in the “one unit start” region in FIG. 2, as long as there is a compressor 2 that is stopped, one unit is started each time the continuous start prevention time elapses.

(1−2)圧力変化率ΔPの絶対値が第一設定値ΔP1以上であるが第二設定値ΔP2未満である場合。具体的には、−ΔP2<ΔP≦−ΔP1である場合。
圧力センサ4の検出圧力Pが台数増加用圧力Aとしての第一下限圧力PL1以下になると1台起動させる。この場合も、1台起動させても第一下限圧力PL1以下を維持する場合、所定の連続起動防止時間を経過するごとに1台起動させるが、即時増加用圧力Bとしての第二下限圧力PL2以下になれば、連続起動防止時間の経過を待つことなくさらにもう1台起動させる。
(1-2) A case where the absolute value of the pressure change rate ΔP is equal to or greater than the first set value ΔP1 but less than the second set value ΔP2. Specifically, when -ΔP2 <ΔP ≦ −ΔP1.
When the detected pressure P of the pressure sensor 4 is equal to or lower than the first lower limit pressure PL1 as the number increase pressure A, one unit is activated. In this case as well, if the first lower limit pressure PL1 or less is maintained even if one unit is activated, one unit is activated every time a predetermined continuous activation prevention time elapses, but the second lower limit pressure PL2 as the immediately increasing pressure B If it becomes below, another one is started, without waiting for progress of continuous starting prevention time.

つまり、図2において、「1台起動」領域に入ることで1台を起動させても、なおその領域に留まる場合には、停止中の圧縮機2がある限り、連続起動防止時間ごとに1台ずつ圧縮機2を起動させる。また、その間、「さらに1台起動」領域に入れば、連続起動防止時間を経過しないでも、さらに1台を起動させる。   That is, in FIG. 2, if one unit is started by entering the “one unit start” region and still remains in that region, it remains 1 every continuous start prevention time as long as there is a compressor 2 being stopped. The compressor 2 is started one by one. In the meantime, if the “one more unit activation” area is entered, one unit is activated even if the continuous activation prevention time has not elapsed.

(1−3)圧力変化率ΔPの絶対値が第二設定値ΔP2以上である場合。具体的には、ΔP≦−ΔP2である場合。
レシーバタンク3内の圧力下降時(圧力変化率ΔPがマイナスの場合つまりΔP≦−ΔP2の場合)には、圧力センサ4の検出圧力Pが台数増加用圧力Aとしての容量調整弁の制御範囲上限値PH以下、言い換えれば容量調整弁の制御範囲PL〜PHであっても、1台起動させる。この場合も、1台起動させても容量調整弁の制御範囲PL〜PHを維持する場合、所定の連続起動防止時間を経過するごとに1台起動させるが、即時増加用圧力Bとしての第一下限圧力PL1以下になれば、連続起動防止時間の経過を待つことなくさらにもう1台起動させる。
(1-3) The absolute value of the pressure change rate ΔP is equal to or greater than the second set value ΔP2. Specifically, when ΔP ≦ −ΔP2.
When the pressure in the receiver tank 3 drops (when the pressure change rate ΔP is negative, that is, ΔP ≦ −ΔP2), the detection pressure P of the pressure sensor 4 is the upper limit of the control range of the capacity adjustment valve as the pressure A for increasing the number of units. Even if it is below the value PH, in other words, within the control range PL to PH of the capacity adjustment valve, one unit is activated. Also in this case, when the control range PL to PH of the capacity adjusting valve is maintained even if one unit is started, one unit is started every time a predetermined continuous start prevention time elapses. If the pressure falls below the lower limit pressure PL1, another unit is activated without waiting for the continuous activation prevention time to elapse.

つまり、図2において「1台起動」領域に入ることで1台を起動させても、なおその領域に留まる場合には、停止中の圧縮機2がある限り、連続起動防止時間ごとに1台ずつ圧縮機2を起動させる。また、その間、「さらに1台起動」領域に入れば、連続起動防止時間を経過しないでも、さらに1台を起動させる。   That is, even if one unit is started by entering the “one unit start” area in FIG. 2 and still remains in that region, as long as there is a compressor 2 that is stopped, one unit for each continuous start prevention time The compressor 2 is started one by one. In the meantime, if the “one more unit activation” area is entered, one unit is activated even if the continuous activation prevention time has not elapsed.

(2)圧縮機2の運転台数の減少制御
圧力センサ4により空気圧力を監視して、たとえば、2台運転している場合には、1台当たりの負荷率が50%以下になると1台停止させ、3台運転している場合には、1台当たりの負荷率が67%以下になると1台停止させ、4台運転している場合には、1台あたりの負荷率が75%以下になると1台停止させるというように、前述した数式1による停止負荷率を考慮して、圧縮機2の運転台数を減少させる。
(2) Reduction control of the number of operating compressors 2 When the air pressure is monitored by the pressure sensor 4 and, for example, two units are operating, one unit stops when the load factor per unit becomes 50% or less. When three units are operating, one unit is stopped when the load factor per unit is 67% or less. When four units are operating, the unit load rate is 75% or less. In this case, the number of operating compressors 2 is reduced in consideration of the stop load factor according to Equation 1 as described above.

これにより、1台だけ運転している場合には、負荷率が0〜100%で運転され、2台運転している場合には、1台当たりの負荷率が50〜100%で運転され、3台運転している場合には、1台当たりの負荷率が67〜100%で運転されるというように、台数が増すほど高負荷で運転される。   Thereby, when only one unit is operated, the load factor is operated at 0 to 100%, and when two units are operated, the load factor per unit is operated at 50 to 100%. In the case of operating three units, the operation is performed with a higher load as the number of units increases, such as operation with a load factor of 67 to 100% per unit.

圧力に基づく制御を行うには、前述した数式3(または数式2)により求められる運転台数に応じた台数減少用圧力C以上になれば、1台停止させればよい。たとえば、2台運転している場合には、「{(上限圧力PH−下限圧力PL)/2)}+下限圧力PL」以上になると、圧縮機2を1台停止させる。また、3台運転している場合には、「{(上限圧力PH−下限圧力PL)/3}+下限圧力PL」以上になると、圧縮機2を1台停止させるというように、運転中の台数に基づき数式3により台数減少用圧力Cが設定される。   In order to perform the control based on the pressure, it is only necessary to stop one unit if the pressure is not less than the number-decreasing pressure C corresponding to the number of operating units determined by the above-described Formula 3 (or Formula 2). For example, when two units are operating, when “{(upper limit pressure PH−lower limit pressure PL) / 2)} + lower limit pressure PL” or more, one compressor 2 is stopped. In addition, when operating three units, when “{(upper limit pressure PH−lower limit pressure PL) / 3} + lower limit pressure PL” or more, one compressor 2 is stopped so that one compressor is stopped. The number-decreasing pressure C is set according to Equation 3 based on the number.

ここで、圧力センサ4による検出圧力Pが台数減少用圧力C以上の状態を設定時間継続後に、圧縮機2の運転台数を減少させるのが好ましい。これにより、1台を停止させた後に次の1台を停止させるまでに規定の時間を要し、次々と過剰に停止させるおそれがない。   Here, it is preferable to reduce the number of operating compressors 2 after the set time continues for a state in which the pressure P detected by the pressure sensor 4 is equal to or higher than the pressure C for reducing the number of units. As a result, it takes a specified time to stop the next one after stopping one, and there is no risk of stopping one after another.

複数台を同時に運転する場合において、仮に1台だけを容量制御し他を全負荷運転させる場合、容量調整を1台のみで行っているので、空気使用量が急激に減少した場合に、レシーバタンク3内の圧力が過上昇するおそれがある。ところが、本実施例の構成によれば、複数台の圧縮機2を運転する場合でも、すべてを容量制御するので、空気使用量が急激に減少した場合でも、複数台の圧縮機2の容量制御機能が並行して作用することで、レシーバタンク3内の圧力が過上昇するのを防止することができる。たとえ空気使用量が突然に全くなくなったとしても、空気圧力が過上昇することはない。   When operating multiple units at the same time, if only one unit is capacity controlled and the others are operated at full load, the capacity adjustment is performed with only one unit, so if the air usage decreases rapidly, the receiver tank There is a possibility that the pressure in 3 will rise excessively. However, according to the configuration of this embodiment, even when a plurality of compressors 2 are operated, the capacity is controlled for all, so even if the amount of air used is drastically reduced, the capacity control of the plurality of compressors 2 is performed. By the functions acting in parallel, it is possible to prevent the pressure in the receiver tank 3 from rising excessively. Even if the air usage suddenly disappears at all, the air pressure does not rise excessively.

複数台を同時に運転する場合において、仮に1台だけを容量制御し他を全負荷運転させる場合、各圧縮機2には全負荷運転に保持するためのフルロードロック機能が必要となる。ところが、この機能は圧縮機2に標準的に装備されている訳ではなく圧縮機2を改造する必要がある。しかしながら、本実施例のシステム1によれば、各圧縮機2にフルロードロック機能は不要であるから、各圧縮機2を改造する必要がない。   In the case of operating a plurality of units simultaneously, if only one unit is capacity-controlled and the others are operated at full load, each compressor 2 needs a full load lock function for holding at full load operation. However, this function is not normally provided in the compressor 2, and the compressor 2 needs to be modified. However, according to the system 1 of the present embodiment, each compressor 2 does not need a full load lock function, so that it is not necessary to modify each compressor 2.

また、運転台数の増加に応じて台数減少用圧力Cを下げると、運転中の各圧縮機2の負荷率は前述したように上がり、言い換えれば、各圧縮機2は吐出圧力が低い側で運転することになる。そして、一般に、圧縮機2は吐出圧力が低い側で運転するほど高効率なので、台数減少用圧力Cを下げることで、運転効率を向上することができる。   Further, when the pressure C for decreasing the number is lowered in accordance with the increase in the number of operating units, the load factor of each operating compressor 2 increases as described above. In other words, each compressor 2 operates on the side where the discharge pressure is low. Will do. In general, the compressor 2 is more efficient as it operates at a lower discharge pressure. Therefore, the operation efficiency can be improved by lowering the pressure C for decreasing the number of units.

ところで、前記実施例では、各圧縮機2は、容量調整弁により、吐出圧力を上限圧力PHと下限圧力PLとの間に維持するように、その間で容量制御される。つまり、上限圧力PH以上では、容量調整弁が全閉されて圧縮機2の負荷率は0%となり、下限圧力PL以下では、容量調整弁が全開されて圧縮機2の負荷率は100%となり、上限圧力PHと下限圧力PLとの間では、下限圧力PLから上限圧力PHへ行くに従って、容量調整弁の開度が比例的に絞られて、圧縮機2の負荷率や吐出空気量も比例的に減少する。   By the way, in the said Example, capacity | capacitance control of each compressor 2 is carried out between them so that discharge pressure may be maintained between the upper limit pressure PH and the lower limit pressure PL with a capacity | capacitance adjustment valve. That is, when the pressure is higher than the upper limit pressure PH, the capacity adjustment valve is fully closed and the load factor of the compressor 2 is 0%. When the pressure is lower than the lower limit pressure PL, the capacity adjustment valve is fully opened and the load factor of the compressor 2 is 100%. Between the upper limit pressure PH and the lower limit pressure PL, the opening of the capacity adjustment valve is proportionally reduced from the lower limit pressure PL to the upper limit pressure PH, and the load factor and discharge air amount of the compressor 2 are also proportional. Decrease.

従って、圧縮機2の吐出側の圧力により、各圧縮機2の負荷率ひいては吐出空気量を知ることができ、これを利用して下記のとおり制御することで、前記実施例と同様の作用効果を得ることができる。その場合、圧縮機台数制御システム1には、吐出容量(定格時、言い換えれば負荷率100%の全負荷時の吐出空気量)の異なる圧縮機2が含まれていてもよい。また、場合により、下記の制御は、前記実施例の制御に加えて実施(つまり圧縮機の運転台数減少条件をANDに)することもできる。なお、上限圧力、下限圧力、吐出容量は、予め台数制御器5に設定されている。   Therefore, it is possible to know the load factor of each compressor 2 and thus the amount of discharged air from the pressure on the discharge side of the compressor 2, and the following effects are obtained by using this to control as follows. Can be obtained. In that case, the compressor number control system 1 may include compressors 2 having different discharge capacities (in the rated state, in other words, the discharge air amount at the full load with a load factor of 100%). In some cases, the following control can be performed in addition to the control of the above embodiment (that is, the condition for reducing the number of operating compressors is AND). The upper limit pressure, the lower limit pressure, and the discharge capacity are set in the number controller 5 in advance.

まず、台数制御器5は、運転中の圧縮機2について、圧力センサ4の検出圧力に基づき各圧縮機2の負荷率を求めると共に、この負荷率における各圧縮機2からの吐出空気量を求める。さらに、台数制御器5は、運転中の各圧縮機2からの吐出空気量を加算して、運転中のすべての圧縮機2からの総吐出空気量を求める。   First, the number controller 5 obtains the load factor of each compressor 2 based on the detected pressure of the pressure sensor 4 for the compressor 2 in operation, and obtains the amount of air discharged from each compressor 2 at this load factor. . Furthermore, the number controller 5 adds the discharge air amount from each compressor 2 during operation to obtain the total discharge air amount from all the compressors 2 during operation.

たとえば、吐出容量が10m/minの圧縮機2が1台と、吐出容量が5m/minの圧縮機2が1台の合計2台が運転中、圧力センサ4の検出圧力が上限圧力PHと下限圧力PLとのちょうど中間で負荷率50%であるとする。この場合、吐出容量が10m/minの圧縮機2からの吐出空気量は5m/min(=10m/min×0.5)であり、吐出容量が5m/minの圧縮機2からの吐出空気量は2.5m/min(=5m/min×0.5)であり、運転中のすべての圧縮機2からの総吐出空気量は7.5m/minとなる。 For example, when two compressors with a discharge capacity of 10 m 3 / min and one compressor 2 with a discharge capacity of 5 m 3 / min are in operation, the pressure detected by the pressure sensor 4 is the upper limit pressure PH. It is assumed that the load factor is 50% exactly between the lower limit pressure PL and the lower limit pressure PL. In this case, the amount of air discharged from the compressor 2 having a discharge capacity of 10 m 3 / min is 5 m 3 / min (= 10 m 3 /min×0.5), and from the compressor 2 having a discharge capacity of 5 m 3 / min. The discharge air amount is 2.5 m 3 / min (= 5 m 3 /min×0.5), and the total discharge air amount from all the compressors 2 in operation is 7.5 m 3 / min.

そして、台数制御器5は、総吐出空気量が、次停止予定機を除く他の運転中の圧縮機の吐出容量の合計以下であれば、次停止予定機を停止させる。   Then, the number controller 5 stops the next scheduled stop machine if the total discharge air amount is equal to or less than the total discharge capacity of the compressors in operation other than the next scheduled stop machine.

たとえば、上の例で、吐出容量が5m/minの圧縮機2が次停止予定機である場合、「総吐出空気量7.5」≦「次停止予定機を除く他の運転中の圧縮機の吐出容量の合計10」となるから、吐出容量が5m/minの圧縮機2を停止させる。一方、吐出容量が10m/minの圧縮機2が次停止予定機である場合、「総吐出空気量7.5」>「次停止予定機を除く他の運転中の圧縮機の吐出容量の合計5」となるから、吐出容量が10m/minの圧縮機2は停止させない。 For example, in the above example, when the compressor 2 having a discharge capacity of 5 m 3 / min is the next scheduled stop machine, “total discharge air amount 7.5” ≦ “compression during operation other than the next scheduled stop machine” Therefore, the compressor 2 having a discharge capacity of 5 m 3 / min is stopped. On the other hand, when the compressor 2 having a discharge capacity of 10 m 3 / min is the next scheduled stop machine, the “total discharge air amount 7.5”> “the discharge capacity of the compressor during operation other than the next scheduled stop machine Therefore, the compressor 2 having a discharge capacity of 10 m 3 / min is not stopped.

このような制御により、吐出容量の異なる圧縮機2であっても、安定した台数制御が可能となる。なお、ここでは、圧縮機2の運転台数を減少させる制御について説明したが、運転台数を増加させる制御については、前記実施例と同様であるため説明を省略する。   By such control, even if the compressors 2 have different discharge capacities, stable number control is possible. Here, the control for reducing the operating number of the compressors 2 has been described, but the control for increasing the operating number is the same as in the above-described embodiment, and thus the description thereof is omitted.

上述のとおり、圧縮機台数制御システム1は、複数台の圧縮機2を備えるが、これら圧縮機2は、適宜グループ分けされて制御されてもよい。たとえば、優先機グループと非優先機グループとに分けて台数制御器5に設定しておき、台数制御器5は、運転台数を増加させる場合、優先機グループに属する圧縮機2を、非優先機グループに属する圧縮機2よりも優先して起動する一方、運転台数を減少させる場合、非優先機グループに属する圧縮機2を、優先機グループに属する圧縮機2よりも優先して停止する。   As described above, the compressor number control system 1 includes a plurality of compressors 2. However, these compressors 2 may be appropriately grouped and controlled. For example, the priority controller group and the non-priority machine group are set in the unit controller 5 separately, and when the unit controller 5 increases the number of operating units, the compressor 2 belonging to the priority unit group is assigned to the non-priority unit. While starting with priority over the compressors 2 belonging to the group, when reducing the number of operating units, the compressors 2 belonging to the non-priority machine group are stopped with priority over the compressors 2 belonging to the priority machine group.

つまり、起動は、優先機グループに属している圧縮機2から所定のローテーションで行い、優先機グループに属する圧縮機2がすべて運転に入ると、非優先機グループに属する圧縮機2を所定のローテーションで起動させればよい。逆に、停止は、非優先機グループに属している圧縮機2から所定のローテーションで行い、非優先機グループに属する圧縮機2がすべて停止すると、優先機グループに属する圧縮機2を所定のローテーションで停止させればよい。   That is, the start-up is performed by a predetermined rotation from the compressors 2 belonging to the priority machine group, and when all the compressors 2 belonging to the priority machine group enter operation, the compressors 2 belonging to the non-priority machine group are moved to the predetermined rotation. You can start with. Conversely, the stop is performed by a predetermined rotation from the compressor 2 belonging to the non-priority machine group, and when all the compressors 2 belonging to the non-priority machine group are stopped, the compressor 2 belonging to the priority machine group is moved to the predetermined rotation. Just stop.

このようにして、優先機グループに属する圧縮機2の運転を優先することで、たとえば省エネ性の高い圧縮機2の運転を優先することができる。   Thus, by giving priority to the operation of the compressors 2 belonging to the priority machine group, for example, the operation of the compressor 2 with high energy saving can be given priority.

また、圧縮機2として、インバータにより回転数を制御されるインバータ機を備えてもよい。典型的には、複数台の圧縮機2の内、1台がインバータ機とされ、他が吸込絞り機とされる。吸込絞り機とは、前記実施例で述べたように、容量調整弁により上限圧力PHと下限圧力PLとの範囲で容量制御される圧縮機である。   Further, as the compressor 2, an inverter machine whose rotation speed is controlled by an inverter may be provided. Typically, one of the plurality of compressors 2 is an inverter machine, and the other is a suction throttle. The suction throttle is a compressor whose capacity is controlled in a range between an upper limit pressure PH and a lower limit pressure PL by a capacity adjustment valve as described in the above embodiment.

圧縮機2としてインバータ機を備える場合、インバータ機は、最も優先して運転されるように、前記優先機グループとして台数制御器5に設定されるのがよい。そして、インバータ機は、その吐出圧力を、たとえば次式による設定圧力に維持するようにインバータ制御されるのがよい。   When an inverter machine is provided as the compressor 2, the inverter machine is preferably set in the number controller 5 as the priority machine group so that the inverter machine is most preferentially operated. The inverter machine is preferably inverter-controlled so that the discharge pressure is maintained at a set pressure according to the following equation, for example.

[数4] インバータ機の設定圧力=下限圧力±{(上限圧力−下限圧力)×0.1}   [Expression 4] Inverter set pressure = lower limit pressure ± {(upper limit pressure-lower limit pressure) x 0.1}

インバータ機の設定圧力をこのように吸込絞り機の下限圧力PL近辺に設定することで、通常、インバータ機の設定圧力は、台数減少用圧力Cよりも低くなる。これにより、圧力変動の吸収をインバータ機に優先して行わせることができる。また、インバータ機の空気製造により、不必要に台数減少用圧力C以上となって吸込絞り機が停止される不都合も回避される。   By setting the set pressure of the inverter machine in the vicinity of the lower limit pressure PL of the suction throttle in this way, the set pressure of the inverter machine is usually lower than the pressure C for reducing the number of units. Thereby, absorption of a pressure fluctuation can be made to give priority to an inverter machine. Further, the air production of the inverter machine avoids the disadvantage that the suction throttle is stopped unnecessarily due to the pressure C for reducing the number of units.

なお、圧力センサ4による検出圧力以外に、圧縮機2の冷却系統、圧縮機2の電気系統、および圧縮機2からの圧縮空気の利用系統の内、いずれか一以上の状況にも基づき、圧縮機2の運転台数を変更するようにしてもよい。これにより、圧縮機2の冷却系統や電気系統の異常や、急な負荷変動などにも迅速に対応することができる。   In addition to the pressure detected by the pressure sensor 4, the compression is based on one or more of the cooling system for the compressor 2, the electrical system for the compressor 2, and the system for using compressed air from the compressor 2. The number of operating units 2 may be changed. Thereby, it is possible to quickly cope with abnormalities in the cooling system and electric system of the compressor 2 and sudden load fluctuations.

本発明の圧縮機台数制御システム1は、前記実施例(変形例を含む)の構成に限らず適宜変更可能である。特に、各圧縮機2の容量制御の方法は、前記実施例のように圧縮機2の吸込側に設けた容量調整弁に限らず、従来公知の他の構成を採用することもできる。また、特に、圧縮機2の運転台数を増加させる制御については、前記実施例の構成に限らず、従来公知の各種のものを用いることもできる。   The number-of-compressor control system 1 of the present invention is not limited to the configuration of the above-described embodiments (including modifications), and can be changed as appropriate. In particular, the capacity control method of each compressor 2 is not limited to the capacity adjustment valve provided on the suction side of the compressor 2 as in the above-described embodiment, and other conventionally known configurations may be employed. In particular, the control for increasing the number of operating compressors 2 is not limited to the configuration of the above embodiment, and various conventionally known ones can be used.

また、複数台の圧縮機2は、空気負荷に応じて運転台数を変更されるが、その起動の順序または停止の順序は、適宜に設定される。その際、前述したように、省エネ性の高い圧縮機を優先的に運転し、空気負荷に応じて優先順位の低いものから停止させるのがよい。   Further, the number of operating units of the plurality of compressors 2 is changed according to the air load, but the starting order or stopping order is appropriately set. At that time, as described above, it is preferable to preferentially operate the compressor with high energy saving performance and stop the compressor with the low priority according to the air load.

また、優先機グループと非優先機グループとに分けるのに代えて、吐出容量の大小に応じてグループ分けしてもよい。その場合、たとえば、それぞれのグループ内で圧縮機2が順に運転されるように、停止予定機と起動予定機を設定しておく。また、どのグループから次回の起動や停止を行わせるかは、規定パターン、圧力の変化率または空気量の変化で決定すればよい。たとえば、圧縮機2の起動は、吐出容量が小さいもの、大きいもの、小さいもの、…というように、交互に行うことができる。逆に、圧縮機2の停止は、前回起動したグループとは逆のグループに属するものを停止させる。また、連続して停止する場合は、グループを交互とする。さらに、圧力の変化率に基づき、変化率が大きいときは、吐出容量の大きいグループのものを発停し、圧力変化率が小さいときは、吐出容量の小さいグループのものを発停させればよい。さらに、空気量の変化に基づき、空気量の変化が大きいときは、吐出容量の大きいグループのものを発停し、空気量の変化が小さいときは、吐出容量の小さいグループのものを発停させればよい。   Further, instead of dividing into the priority machine group and the non-priority machine group, the machine may be grouped according to the discharge capacity. In that case, for example, the scheduled stop machine and the scheduled start machine are set so that the compressor 2 is operated in order in each group. Further, from which group the next activation or deactivation is performed may be determined based on the prescribed pattern, the rate of change in pressure, or the amount of air. For example, the compressor 2 can be activated alternately such that the discharge capacity is small, large, small, and so on. On the contrary, the stop of the compressor 2 stops those belonging to the group opposite to the previously activated group. When stopping continuously, the groups are alternated. Further, based on the rate of change in pressure, when the rate of change is large, the group having a large discharge capacity is started and stopped, and when the rate of change in pressure is small, the group having a small discharge capacity may be started and stopped. . Furthermore, based on the change in air volume, when the air volume change is large, start and stop the group with the large discharge capacity, and when the air volume change is small, start and stop the group with the small discharge volume. Just do it.

さらに、前記実施例では、各圧縮機2からの圧縮空気はレシーバタンク3を介して圧縮空気利用機器へ送り、そのレシーバタンク3に圧力センサ4を設けたが、レシーバタンク3以外に、各圧縮機2から圧縮空気が供給される箇所、あるいは圧縮空気利用機器へ圧縮空気を送る箇所に、圧力センサ4を設けてもよい。   Furthermore, in the said Example, although the compressed air from each compressor 2 was sent to the apparatus using compressed air via the receiver tank 3, and the pressure sensor 4 was provided in the receiver tank 3, in addition to the receiver tank 3, each compression The pressure sensor 4 may be provided at a location where the compressed air is supplied from the machine 2 or a location where the compressed air is sent to the device using the compressed air.

1 圧縮機台数制御システム
2 圧縮機
3 レシーバタンク
4 圧力センサ
5 台数制御器
A 台数増加用圧力
B 即時増加用圧力
C 台数減少用圧力
DESCRIPTION OF SYMBOLS 1 Compressor number control system 2 Compressor 3 Receiver tank 4 Pressure sensor 5 Number controller A Number of units increase pressure B Immediate increase pressure C Number of units decrease pressure

Claims (4)

複数台の圧縮機と、
これら圧縮機から圧縮空気が供給されると共に圧縮空気利用機器へ圧縮空気を送る箇所に設けられ、圧縮空気の圧力を検出する圧力センサと、
この圧力センサの検出圧力に基づき前記圧縮機の運転台数を変更する台数制御器とを備え、
前記台数制御器により運転台数を減少させるか否かの境界値としての台数減少用圧力は運転台数が多いほど低くなる圧縮機台数制御システムであって、
前記複数台の圧縮機として、吐出容量の異なる圧縮機が含まれ、
前記各圧縮機は、吐出圧力を上限圧力と下限圧力との間に維持するように、その間で容量制御されると共に、上限圧力以上で負荷率0%、下限圧力以下で負荷率100%とされ、
運転中の圧縮機について、前記圧力センサの検出圧力に基づき各圧縮機の負荷率を求めると共に、この負荷率における各圧縮機からの吐出空気量を求めて、これにより運転中のすべての圧縮機からの総吐出空気量を求め、
この総吐出空気量が、次停止予定機を除く他の運転中の圧縮機の吐出容量の合計以下であれば、次停止予定機を停止させる
ことを特徴とする圧縮機台数制御システム。
Multiple compressors,
A pressure sensor for detecting the pressure of the compressed air, which is provided at a location where the compressed air is supplied from these compressors and the compressed air is sent to the device using the compressed air;
A number controller for changing the number of operating compressors based on the pressure detected by the pressure sensor,
The number reduction pressure as a boundary value whether or not to reduce the number of operating units by the number controller is a compressor number control system that decreases as the number of operating units increases,
The plurality of compressors include compressors with different discharge capacities,
Each compressor is capacity-controlled between the upper limit pressure and the lower limit pressure so that the discharge pressure is maintained between the upper limit pressure and the lower limit pressure. The load factor is 0% above the upper limit pressure, and the load factor is 100% below the lower limit pressure. ,
For compressors in operation, the load factor of each compressor is obtained based on the detected pressure of the pressure sensor, and the amount of air discharged from each compressor at this load factor is obtained, whereby all compressors in operation are obtained. The total amount of air discharged from
A compressor number control system characterized in that the next scheduled stop machine is stopped if the total amount of discharged air is equal to or less than the total discharge capacity of compressors in operation other than the next scheduled stop machine.
前記圧縮機は、優先機グループと非優先機グループとに分けられており、
前記台数制御器は、運転台数を増加させる場合、優先機グループに属する圧縮機を、非優先機グループに属する圧縮機よりも優先して起動し、
前記台数制御器は、運転台数を減少させる場合、非優先機グループに属する圧縮機を、優先機グループに属する圧縮機よりも優先して停止する
ことを特徴とする請求項1に記載の圧縮機台数制御システム。
The compressor is divided into a priority machine group and a non-priority machine group,
The number controller, when increasing the number of operating units, starts the compressor belonging to the priority machine group in preference to the compressor belonging to the non-priority machine group,
2. The compressor according to claim 1, wherein, when the number of operating units is decreased, the compressor belonging to the non-priority machine group is stopped in preference to the compressor belonging to the priority machine group. Unit control system.
圧縮機として、インバータにより回転数を制御されるインバータ機を備えると共に、これ以外は、容量調整弁により上限圧力と下限圧力との範囲で容量制御される吸込絞り機とされ、
前記インバータ機は、最も優先して運転されるように、前記優先機グループとして前記台数制御器に設定されており、
前記吸込絞り機は、その吐出圧力を、下限圧力と上限圧力との間に維持するように容量制御され、
前記インバータ機は、その吐出圧力を、次式による設定圧力に維持するようにインバータ制御される
ことを特徴とする請求項2に記載の圧縮機台数制御システム。
インバータ機の設定圧力=下限圧力±{(上限圧力−下限圧力)×0.1}
As a compressor, an inverter machine whose rotational speed is controlled by an inverter is provided, and other than this, a suction throttle machine whose capacity is controlled in a range between an upper limit pressure and a lower limit pressure by a capacity adjustment valve,
The inverter machine is set in the number controller as the priority machine group so as to be operated with the highest priority,
The suction throttle is capacity-controlled to maintain its discharge pressure between a lower limit pressure and an upper limit pressure,
The said inverter machine is inverter-controlled so that the discharge pressure may be maintained at the setting pressure by following Formula. The compressor number control system of Claim 2 characterized by the above-mentioned.
Inverter set pressure = lower limit pressure ± {(upper limit pressure-lower limit pressure) x 0.1}
前記圧力センサによる検出圧力以外に、前記圧縮機の冷却系統、および/または、前記圧縮機の電気系統、および/または、前記圧縮機からの圧縮空気の利用系統の状況にも基づき、前記圧縮機の運転台数を変更する
ことを特徴とする請求項1〜3のいずれか1項に記載の圧縮機台数制御システム。
In addition to the pressure detected by the pressure sensor, the compressor is also based on the status of the cooling system of the compressor and / or the electrical system of the compressor and / or the utilization system of compressed air from the compressor. The number-of-compressor control system according to any one of claims 1 to 3, wherein the number of operating units is changed.
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