阅读说明：本技术 一种农用除草剂原药生产的联锁控制加氢反应方法 (Interlocking control hydrogenation reaction method for agricultural herbicide technical production ) 是由 吴凤军 张乐乐 杨海岗 劳永亮 吴艳芳 曾晓龙 安典营 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种农用除草剂原药的联锁控制合成方法,包括高压反应釜,高压反应釜上连接有进料输送管道上、进料电磁阀和进料流量计；进气输送管道、进气电磁阀、进气流量计和进气压力传感器、排气管道、缓冲罐、安全阀、釜内温度和压力传感器,各阀、流量计、传感器均连接到控制柜；进行反应时,进气电磁阀、釜内压力传感器通过控制系统和泄压安全阀联锁；在反应过程中,当反应釜内压力值超出预设值时,控制系统控制进料电磁阀关闭,并打开泄压安全阀,使釜内气体进入缓冲罐,降低釜内压力。本发明实现了对进料量、气体压力以及反应的温度压力的精确控制,提高了安全性,又降低了成本,易于实现,有利于产品在农业上的推广。(The invention discloses an interlocking control synthesis method of agricultural herbicide technical, which comprises a high-pressure reaction kettle, wherein the high-pressure reaction kettle is connected with a feeding conveying pipeline, a feeding electromagnetic valve and a feeding flowmeter; the device comprises an air inlet conveying pipeline, an air inlet electromagnetic valve, an air inlet flow meter, an air inlet pressure sensor, an exhaust pipeline, a buffer tank, a safety valve and a temperature and pressure sensor in a kettle, wherein all valves, flow meters and sensors are connected to a control cabinet; when the reaction is carried out, the air inlet electromagnetic valve and the pressure sensor in the kettle are interlocked through the control system and the pressure relief safety valve; in the reaction process, when the pressure value in the reaction kettle exceeds a preset value, the control system controls the feeding electromagnetic valve to be closed and opens the pressure relief safety valve, so that gas in the kettle enters the buffer tank, and the pressure in the kettle is reduced. The invention realizes the accurate control of the feeding quantity, the gas pressure and the reaction temperature and pressure, improves the safety, reduces the cost, is easy to realize and is beneficial to the popularization of the product in agriculture.)

1. An interlocking control hydrogenation reaction method for agricultural herbicide technical production is characterized in that a reaction device comprises a high-pressure reaction kettle, wherein a feeding conveying pipeline for conveying 2-methyl-6-ethyl phenyl-imine is connected to the high-pressure reaction kettle, and a feeding electromagnetic valve and a feeding flowmeter are arranged on the feeding conveying pipeline;

the high-pressure reaction kettle is connected with an air inlet conveying pipeline for conveying hydrogen, and an air inlet electromagnetic valve, an air inlet flow meter and an air inlet pressure sensor are arranged on the air inlet conveying pipeline;

one side of the high-pressure reaction kettle is connected with a buffer tank through an exhaust pipeline, and a pressure relief safety valve is arranged on the exhaust pipeline;

the high-pressure reaction kettle is provided with a kettle temperature sensor and a kettle internal pressure sensor for monitoring the temperature and the pressure in the kettle;

the feeding electromagnetic valve, the feeding flow meter, the air inlet electromagnetic valve, the air inlet flow meter, the air inlet pressure sensor, the pressure relief safety valve, the temperature sensor in the kettle and the pressure sensor in the kettle are all connected to the control cabinet;

when the reaction is carried out, the control cabinet controls the feeding electromagnetic valve to be opened, 2-methyl-6-ethyl phenyl-imine is pumped into the reaction kettle, the feeding flowmeter collects the conveyed flow and sends the flow to the control cabinet, and after the feeding is finished, the control cabinet controls the air inlet electromagnetic valve to be opened to send hydrogen and start the reaction;

wherein the air inlet electromagnetic valve and the pressure sensor in the kettle are interlocked through a control system and a pressure relief safety valve; in the reaction process, when the pressure value in the reaction kettle exceeds 1.2 times of the preset value, the control system controls the feeding electromagnetic valve to be closed and opens the pressure relief safety valve, so that the gas in the kettle enters the buffer tank, and the pressure in the kettle is reduced.

2. The interlocking control hydrogenation reaction method for producing agricultural herbicide technical according to claim 1, characterized in that a catalyst is arranged in the high-pressure reaction kettle.

3. The interlocking control hydrogenation reaction method for agricultural herbicide technical production according to claims 1-2, characterized in that the preset value is 6-8 MPa.

4. The interlocking control synthesis method of an agricultural herbicide technical material as claimed in claims 1 to 3, wherein the in-kettle temperature sensor is used for monitoring the temperature in the reaction kettle in real time and transmitting the reaction temperature to the control cabinet.

Technical Field

The invention relates to the technical field of production and preparation of raw pesticide of agricultural herbicide products, in particular to an interlocking control hydrogenation reaction method for production of raw pesticide of agricultural herbicide.

Background

Along with the continuous development of society, people pay more and more attention to the requirements of agricultural production, and in modern agricultural production, the requirements on related pesticides such as herbicides are larger and larger, so that the production scale is enlarged, and high-efficiency safe production is imperative. The s-metolachlor is a novel environment-friendly herbicide with high efficiency and high selectivity, can be used for various crops, has the characteristics of safety, high efficiency, low toxicity, low residue, environmental friendliness and the like, is the fourth most herbicide in the world, and is a backbone variety of the herbicide in developed countries and regions such as European Union, America and the like. However, one of the main problems of the product popularized in China at present is that the production cost is too high, the product price is also high, and therefore large-area popularization is difficult at present, and therefore a preparation method which is suitable for large-scale industrial production and has low cost is found, and the preparation method has important significance for popularization of the herbicide in agriculture. At present, the synthesis method of the s-metolachlor produced by the applicant adopts an asymmetric catalytic synthesis process, and comprises four steps of synthesis of an intermediate methoxy acetone, alkylation dehydration reaction, hydrogenation reduction reaction and acylation reaction, wherein the hydrogenation reduction reaction is to add an intermediate imine, a chiral catalyst and an organic solvent into a high-pressure reaction kettle, and introduce H2 under certain temperature and pressure conditions for reaction to obtain an intermediate 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) amine. The reaction process requires the addition of feedstock, catalyst and hydrogen. In order to obtain good yield, the requirements on the temperature and pressure of the reaction need to be accurately controlled, meanwhile, the safety requirement on the reaction is strict due to the existence of hydrogen, and currently, for the method of the reaction device, a good monitoring interlocking device and a good monitoring interlocking method are also lacked, so that the reaction yield is not high, and potential safety hazards are brought.

Disclosure of Invention

In order to solve the technical problem, the invention provides an automatic feeding control method in chemical reaction.

The complete technical scheme of the invention comprises the following steps:

an interlocking control hydrogenation reaction method for agricultural herbicide technical production, wherein a reaction device comprises a high-pressure reaction kettle, a feeding conveying pipeline for conveying 2-methyl-6-ethyl phenyl-imine is connected to the high-pressure reaction kettle, and a feeding electromagnetic valve and a feeding flowmeter are arranged on the feeding conveying pipeline;

the high-pressure reaction kettle is connected with an air inlet conveying pipeline for conveying hydrogen, and an air inlet electromagnetic valve, an air inlet flow meter and an air inlet pressure sensor are arranged on the air inlet conveying pipeline;

one side of the high-pressure reaction kettle is connected with a buffer tank through an exhaust pipeline, and a pressure relief safety valve is arranged on the exhaust pipeline;

the high-pressure reaction kettle is provided with a kettle temperature sensor and a kettle internal pressure sensor for monitoring the temperature and the pressure in the kettle;

the feeding electromagnetic valve, the feeding flow meter, the air inlet electromagnetic valve, the air inlet flow meter, the air inlet pressure sensor, the pressure relief safety valve, the temperature sensor in the kettle and the pressure sensor in the kettle are all connected to the control cabinet;

when the reaction is carried out, the control cabinet controls the feeding electromagnetic valve to be opened, 2-methyl-6-ethyl phenyl-imine is pumped into the reaction kettle, the feeding flowmeter collects the conveyed flow and sends the flow to the control cabinet, and after the feeding is finished, the control cabinet controls the air inlet electromagnetic valve to be opened to send hydrogen and start the reaction;

wherein the air inlet electromagnetic valve and the pressure sensor in the kettle are interlocked through a control system and a pressure relief safety valve; in the reaction process, when the pressure value in the reaction kettle exceeds 1.2 times of the preset value, the control system controls the feeding electromagnetic valve to be closed and opens the pressure relief safety valve, so that the gas in the kettle enters the buffer tank, and the pressure in the kettle is reduced.

Preferably, a catalyst is arranged in the high-pressure reaction kettle.

Preferably, the preset value is 6-8 MPa.

Preferably, the temperature sensor in the reaction kettle is used for monitoring the temperature in the reaction kettle in real time and transmitting the reaction temperature to the control cabinet.

The invention adopts an industrial automatic control system to automatically monitor and control the feeding, gas inlet and reaction processes in the process of the metolachlor hydrogenation reaction, realizes the accurate control of the feeding quantity, the gas pressure and the temperature and the pressure of the reaction, improves the reaction yield, realizes the interlocking control through various sensing monitoring devices, and improves the safety by additionally arranging a pressure relief channel and a buffer tank containing hydrogen gas in a kettle. The method meets the requirement of industrial production, reduces the cost, is easy to realize and is beneficial to the popularization of the product in agriculture in China.

Drawings

FIG. 1 is a schematic diagram of a synthetic method of a hydrogenation reduction reaction.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only illustrative and are not intended to limit the present application.

The invention is further explained by taking the production process of the original drug of the metolachlor as an example, the synthesis method of the metolachlor adopts an asymmetric catalytic synthesis process, comprises four steps of synthesis of intermediate methoxy acetone, alkylation dehydration reaction, hydrogenation reduction reaction and acylation reaction, and researches in laboratories show that the synthesis by the technical route can shorten the reaction time, improve the conversion rate and ensure reasonable cost. However, for industrial application, it is very important to convert small-dose production in a laboratory into industrial large-scale production, and to realize safe, short-production-cycle, and high-efficiency production. Therefore, the applicant develops verification and research of large-scale production aiming at each link in the synthesis process and designs automation of the whole production process.

Aiming at the hydrogenation reduction reaction, the intermediate imine, the chiral catalyst and the organic solvent are added into a high-pressure reaction kettle, and H is introduced under certain temperature and pressure conditions₂Reacting to obtain an intermediate 1-methoxy propyl-2- (2-methyl-6-ethyl phenyl)) An amine.

The synthesis method of the process is shown in figure 1, the synthesis device comprises a high-pressure reaction kettle 1, a catalyst is placed in the high-pressure reaction kettle 1, a feeding conveying pipeline 2 for conveying 2-methyl-6-ethyl phenyl-imine is connected to the high-pressure reaction kettle 1, and a feeding electromagnetic valve 3 and a feeding flowmeter 4 are arranged on the feeding conveying pipeline.

An air inlet conveying pipeline 5 for conveying hydrogen is connected above the high-pressure reaction kettle 1, and an air inlet electromagnetic valve 5, an air inlet flow meter 7 and a pressure sensor 8 are arranged on the air inlet conveying pipeline 5.

One side of the high-pressure reaction kettle 1 is connected with a buffer tank 10 through an air supply pipeline, and a safety valve 9 is arranged on an exhaust pipeline.

The feed solenoid valve 3, the feed flow meter 4, the intake solenoid valve 5, the intake flow meter 7, the pressure sensor 8 and the safety valve 9 are all connected to a control cabinet 11.

The high-pressure reaction kettle is simultaneously provided with an in-kettle temperature sensor 12 and an in-kettle pressure sensor 13 for monitoring the temperature and the pressure in the kettle, and the temperature and the pressure sensors are also connected to the control cabinet 11.

When the reaction is carried out, the control cabinet controls each electromagnetic valve to be opened according to preset parameters, 2-methyl-6-ethyl phenyl-imine is pumped into the reaction kettle, the feed flowmeter collects the conveyed flow and sends the flow to the control cabinet, hydrogen is added to start the reaction after the preset amount is reached, and the electromagnetic valve for conveying the hydrogen, the pressure sensor, the temperature sensor in the high-pressure valve and the pressure sensor are interlocked with the control system and the pressure relief safety valve. The reaction temperature is controlled to be 50 +/-5 ℃ in the synthesis process, and the hydrogen pressure is controlled to be 6-8 MPa. In the reaction process, when the pressure value in the reaction kettle exceeds 1.2 times of the preset value, the control system controls the feeding electromagnetic valve to be closed and opens the pressure relief safety valve, so that the gas in the kettle enters the buffer tank, and the pressure in the kettle is reduced.

2-methyl-6-ethyl phenyl-imine, 1-S-diphenyl phosphine-2-R-bis (3, 5-dimethyl phenyl) phosphine cyclopentadienyl ruthenium and iridium bromide are added into a high-pressure reaction kettle, and the mass ratio of the 2-methyl-6-ethyl phenyl-imine to the iridium bromide is as follows: 1-S-diphenylphosphino-2-R-bis (3, 5-dimethylphenyl) phosphinotrien-ruthenium: iridium bromide 38000:10: 2. Controlling the reaction temperature to be 50 +/-5 ℃, the reaction time to be 6 hours, and the hydrogen pressure to be 6-8 MPa, and obtaining the 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) amine after the reaction is finished.

It should be noted that the interlocking control hydrogenation reaction method and apparatus are also applicable to the nitration reaction of pendimethalin and mesosulfuron and other processes, for example, the synthesis process of pendimethalin produced by the present applicant includes two steps of nitration reaction and denitritification reaction, wherein the nitration reaction is to add nitre into a reaction kettle, and add the mixture of aniline and organic solvent under certain temperature and pressure to react to obtain pendimethalin and nitrosopendimethalin. The reaction process requires the addition of aniline, nitric acid and an organic solvent. The above preparation process has similar requirements for the apparatus, so the dehydration apparatus of the present invention can be used in the preparation process of the above crude drug.

The other links of the s-metolachlor technical of the invention are explained below.

1. And (3) carrying out catalytic dehydrogenation reaction to synthesize intermediate methoxy acetone:

the process adopts a tubular fixed bed reactor, a plurality of reaction tubes are arranged in the reactor, each reaction tube is filled with a Cu/ZnO catalyst, the diameter of the tube is 10cm, the length of the tube is 1.5m, inert magnetic ring fillers with different sizes are filled in sections at the ends, the bottom of the reactor is connected with a feed pipeline, a feed electromagnetic valve and a feed flowmeter are arranged on the feed channel, an air outlet pipeline is arranged at the top of the reactor, a pressure sensor and an air outlet flowmeter are arranged on the air outlet pipeline, and the electromagnetic valve, the pressure sensor and the flowmeters are all connected to a control cabinet.

When the reaction is carried out, the control cabinet controls the feeding electromagnetic valve to be opened, liquid raw material 1-methoxy-2-propanol is added into the reactor from the feeding pipeline through the plunger pump, the feeding flowmeter measures the feeding and transmits the feeding back to the control cabinet, meanwhile, the electric heating device is adopted to heat the reactor, the 1-methoxy-2-propanol generates methoxy acetone under the catalysis effect, the generated hydrogen is discharged from the gas outlet pipeline, the gas outlet flowmeter transmits the hydrogen flow to the control cabinet, the control cabinet calculates the generated hydrogen quality according to the volume flow of the hydrogen and the pressure data transmitted back by the pressure sensor, and monitors the relation between the discharged hydrogen quality in a certain time and the time. The reaction is considered to be normal when the hydrogen amount floats within +/-10% in the time period, when the hydrogen amount continuously decreases and exceeds 10%, a warning is sent out, and after the hydrogen amount continuously decreases and exceeds 20%, the control cabinet control system stops and the catalyst is replaced in time.

The reaction formula of the step is as follows:

meanwhile, in the actual industrial production of the step, the dehydrogenation conversion rate and the speed of the reaction need to be comprehensively considered, although the dehydrogenation conversion rate can be improved by prolonging the reaction time, the production takt can be prolonged, the production efficiency is reduced, and the improper shortening of the reaction time can possibly cause the too low dehydrogenation conversion rate, thereby causing waste, improving the cost and being not beneficial to environmental protection.

The reaction speed mainly depends on the amount of the 1-methoxy-2-propanol added and the reaction conditions, and in the invention, the research shows that in the process, under the condition of a certain amount of raw material added, the bulk density, the amount, the reaction temperature and the like of the used catalyst can cause different reaction speeds and dehydrogenation conversion rates, and the conversion rate of the raw material greatly changes under different combination parameters. Therefore, according to the actual industrial requirements, the reaction speed and yield for industrial production are ensured, and the dehydrogenation conversion rate is maintained at a higher level to improve the yield. In the actual production, the influence of various parameter changes in the reaction process on the reaction is respectively researched, parameters with obvious effects are selected, and the following defined relationship is obtained through analysis fitting and actual production verification:

in the formula: t is reaction temperature, and the control range is 220-280 ℃; a is a conversion coefficient which represents other factors which are not obviously influenced in actual productionThe comprehensive effect is that the value range is 6.2-10.6; rho is the bulk density of the Cu/ZnO catalyst, and the value range is 700-750 Kg/m³(ii) a L is the amount of 1-methoxy-2-propanol fed in unit time, and the range is 10-30 Kg/h; s is the specific surface area of the catalyst and has a value range of 120-150 m²(ii) in terms of/g. In the actual reaction process, under the condition that parameters such as the adding amount of the 1-methoxy-2-propanol, the bulk density of the catalyst and the like are fixed, the proper reaction temperature is selected, and the reaction speed and the dehydrogenation reaction rate are ensured.

2. Alkylation dehydration reaction, synthesis of intermediate 1-methoxy propyl-2- (2-methyl-6-ethyl phenyl) imine:

the reaction formula of the step is as follows:

the alkylation dehydration reaction is to add intermediate methoxy acetone, 2-methyl-6-ethyl aniline and organic solvent into a reaction kettle, react at a certain temperature, and obtain intermediate imine by rectification after the reaction is finished. The feeding in the process is carried out by adopting the automatic control method, and the method adopts an automatic control device which comprises a reaction kettle, a conveying system, a reaction monitoring system and a control system.

The reaction kettle is used as a reaction container and is connected with a conveying system, the conveying system comprises a first conveying pipeline, the first conveying pipeline is connected with a 2-methyl-6-ethylaniline storage tank, and a first conveying pump, a first electromagnetic valve and a first flowmeter are arranged on the first conveying pipeline.

The organic solvent benzene storage tank is connected with the first conveying pipeline, and a first conveying pump, a first electromagnetic valve and a first flowmeter are arranged on the first conveying pipeline.

The reaction device also comprises a third conveying pipeline, wherein the third conveying pipeline is connected with the intermediate 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) imine reaction fixed bed in the previous working procedure, a buffer tank is arranged between the third conveying pipeline and the fixed bed, and a third conveying pump, a third electromagnetic valve and a third flowmeter are arranged on the third conveying pipeline.

The control system is a PLC, all the electromagnetic valves and the flow meters are connected to the PLC, and real-time flow is transmitted to the PLC.

The reaction monitoring system comprises a temperature sensor and a pressure sensor which are arranged on the reaction kettle, and transmits the real-time reaction pressure and temperature to the PLC.

When the reaction is carried out, the control system respectively controls the electromagnetic valves to be opened according to preset parameters, and the delivery pumps respectively pump 2-methyl-6-ethylaniline, benzene and 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) imine according to the ratio of 2-methyl-6-ethylaniline: methoxy acetone: benzene 7.5: 15: a flow ratio of 12 was fed into the reactor. Each flowmeter is respectively gathered real-time flow on each pipeline, every 0.5 second is gathered once to give PLC with flow data transmission, PLC calculates the contrast and regulates and control the flow data of gathering, and the concrete mode is: the PLC adds the flow data collected by each conveying pipeline respectively and compares the accumulated values, and the conveying time, the collecting time and the frequency are consistent, so that the volume ratio of each raw material can be reflected by the accumulated values. In particular to the selection of the cumulative flow L of intermediate methoxy acetone₃As a reference value, and 2-methyl-6-ethylaniline L₁And cumulative flow L of benzene₂Dividing by a reference value, and calculating the following two parameters in real time:

when sigma is₁Or σ₂When the pressure is more than 0.5% or less than-0.5%, the control system controls the electromagnetic valve on the corresponding pipeline to open/close for a short time. E.g. as sigma₁If the value is too high, the first electromagnetic valve is closed for a short time, and the feeding amount of the 2-methyl-6-ethylaniline is reduced. Otherwise, the feeding amount of the methoxy acetone and the benzene is closed for a short time. Mapping the overall traffic ratioSynthesizing preset 2-methyl-6-ethyl aniline: methoxy acetone: benzene 7.5: 15: 12, controlling the reaction temperature to be 75-90 ℃ and the reaction time to be 9-10 hours. After the reaction is finished, benzene is separated out by a decompression method, and the residual reaction liquid is distilled to obtain a liquid product 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) imine.

3. Hydrogenation reduction reaction

As previously described.

4. Acylation reaction: preparation of s-metolachlor

The reaction formula of the step is as follows:

this process's reaction unit includes reation kettle, reation kettle has mechanical stirring device, specifically include the agitator motor of top, agitator motor is connected with the transmission pivot, be equipped with stirring paddle leaf in the pivot, stirring paddle leaf is including the first stirring paddle leaf that is located the top and the second stirring paddle leaf that is located the below, wherein second stirring paddle leaf is less than first stirring paddle leaf, and the camber of its shape and reation kettle bottom is along with the shape, this is because be the arc at the bottom of the used reation kettle, in order to can the intensive mixing, prevent that the liquid reaction of bottom is not abundant, on traditional stirring paddle basis, a less second stirring paddle has been add, follow the shape at the bottom of its shape and reation kettle, the liquid that can the intensive mixing bottom.

A first feeding pipeline is arranged at one side of the reaction kettle, a first electromagnetic valve and a first flowmeter are arranged on the first feeding pipeline, a second feeding pipeline is arranged at the other side of the reaction kettle, a second electromagnetic valve and a second flowmeter are arranged above the second feeding pipeline,

a third feeding pipeline is arranged above the reaction kettle, a third electromagnetic valve and a third flow meter are arranged above the third feeding pipeline,

inside rain drop mechanism that is equipped with of reation kettle, this rain drop mechanism is located reation kettle inside top, for circular corrosion resistant plate, even hole has been seted up on the board, when carrying out the reaction, the liquid of top passes through in the third conveying pipeline gets into the cauldron, and in the reaction liquid of below with the mode dropwise add of drenching through the hole on the circular corrosion resistant plate, such design is because when carrying out laboratory research, the benzene solution of this process chloracetyl chloride is through dropwise add the reaction solution, but when carrying out industrial production, can not add with dropwise mode, nevertheless because reaction rate can not be too fast, consequently, the drop mechanism of formula of drenching has been designed to the reference, the benzene solution of messenger chloracetyl chloride gets into below reaction solution with reasonable speed, reaction efficiency is improved. A gas discharge pipeline is arranged above the reaction kettle.

During the acylation reaction, firstly, a preset amount of sodium carbonate is put into a reaction kettle, then the control cabinet controls the first electromagnetic valve to be opened, and 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) amine is fed into the reaction kettle through a first feeding pipeline; opening a second electromagnetic valve, feeding benzene into a second feeding pipeline, wherein the dosage ratio of the benzene to the benzene feeding pipeline is 1-methoxypropyl-2- (2-methyl-6-ethylphenyl) amine: sodium carbonate: 40.5Kg of benzene: 33.4 Kg: 220L, then the motor drives the rotating shaft and the paddle to start rotating, and stirring is carried out at the rotating speed of 180rpm, so that the liquid is fully mixed. And then the third electromagnetic valve is opened, the third feeding pipeline sends the benzene solution of the chloracetyl chloride into the kettle, the benzene solution is dripped into the reaction liquid below the kettle through the rain dropping mechanism, at the moment, the paddle continuously and slowly stirs at the rotating speed of 60rpm, and the reaction is finished after 1 h. And after the reaction is finished, the raw material enters a desolventizing kettle for desolventizing to obtain the original metolachlor.

The above applications are only some embodiments of the present application. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept herein, and it is intended to cover all such modifications and variations as fall within the scope of the invention.