阅读说明：本技术 一种水泵的保护方法 (Protection method of water pump ) 是由 周神文 沈云荣 王涛 何来 于 2021-01-20 设计创作，主要内容包括：本发明为一种水泵的保护方法,属于水泵智能控制领域,针对现有水泵控制方法有局限性会影响水泵使用寿命的问题,采用技术方案如下：一种水泵的保护方法,包括如下步骤：步骤1,设置参数、收集信息；步骤1.1,根据不同情况分别执行步骤2.1和步骤2.2；步骤2.1,若P-(real)＜P-(wl),并记录持续时间T-(keep)；当T-(keep)≥T-(set)则执行步骤3；步骤2.2,若P-(real)＜P-(target),则并记录T-s内最大压力P-(max)和最小压力P-(min)；当P-(max)-P-(min)>0.2bar,则记录时间T-(keep),当T-(keep)≥T-(set)则执行步骤3；步骤3,控制器控制水泵停止运行。本方法避免水泵频繁启停,并提高水泵控制精度。(The invention discloses a protection method of a water pump, belongs to the field of intelligent control of water pumps, and aims to solve the problem that the service life of the water pump is influenced by the limitation of the existing water pump control method, the technical scheme is as follows: a protection method of a water pump comprises the following steps: step 1, setting parameters and collecting information; step 1.1, respectively executing step 2.1 and step 2.2 according to different conditions; step 2.1, if P real ＜P wl And recording the duration T keep (ii) a When T is keep ≥T set Executing the step 3; step 2.2, if P real ＜P target Then and record T s Internal maximum pressure P max And a minimum pressure P min (ii) a When P is present max ‑P min >0.2bar, the time T is recorded keep When T is keep ≥T set Executing the step 3; step 3, controlThe controller controls the water pump to stop running. The method avoids frequent start and stop of the water pump and improves the control precision of the water pump.)

1. A protection method of a water pump is characterized by comprising the following steps:

step 1, setting parameters of a controller, collecting information detected by each detection element through the controller, and judging the state of a water pump;

step 1.1, the controller judges whether the water pressure is in a stable state or a fluctuation state by combining the water pressure sensed by the pressure sensor at the water outlet, and the specific operation is as follows: by controllingThe device records unit time T_sMaximum pressure P of internal water pressure_maxAnd a minimum pressure P_minAnd determining whether P is satisfied_max-P_minIf the pressure is more than 0.2bar, if not, the pressure is in a stable state, and the step 2.1 is executed; if yes, the device is in a fluctuation state, and then step 2.2 is executed; wherein the maximum pressure P_maxAnd a minimum pressure P_minEvery unit time T_sUpdating once;

step 2, adjusting:

step 2.1, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the set pressure P_wlIf not, not recording; if yes, calculating the duration T by a timer_keep1And step 2.1.1 is executed;

step 2.1.1, the controller will last for a time T_keep1And a set time T_set1Comparing and determining whether T is satisfied_keep1≥T_set1If not, not recording; if yes, the water shortage indicator lamp is turned on, the water pump enters a water shortage protection state, and step 3 is executed;

step 2.2, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the target pressure P_targetIf not, not recording; if yes, calculating the duration time T by a timer_keep2And step 2.2.1 is executed;

step 2.2.1, the controller will last for a time T_keep2And a set time T_set2Comparing and determining whether T is satisfied_keep2≥T_set2If not, not recording, if yes, lighting a water shortage indicator lamp, enabling the water pump to enter a water shortage protection state, and executing the step 3;

and 3, controlling the water pump to stop running by the controller.

2. The method for protecting the water pump according to claim 1, further comprising the steps of:

step 1.2, sensing the actual temperature T of the pump cavity by using a temperature sensor_realThe controller will control the actual temperature T_realAnd a critical temperature T_dComparing and judgingWhether or not T is satisfied_real≥T_dIf not, the recording is not carried out, if yes, a timer is adopted to record the continuous time t_dAnd executing step 1.2.1;

step 1.2.1, the controller will last for a time t_dAnd a set time t_sComparing and judging whether t is satisfied_d≥t_sAnd if so, entering an over-temperature protection state and executing the step 3.

3. Method for protecting a water pump according to claim 1, characterized in that the set pressure P_wlMaximum value of (P)_wl,maxThe conditions are satisfied as follows: p_wl,max＝P_targetXG/100, wherein P_targetThe value of [1.0,9.0 ]]bar, G is start percentage, and the value range is [10,90 ]]。

4. Method for protecting a water pump according to claim 1, characterized in that T_set1And T_set2Value of [10,180]s。

5. Method for protecting a water pump according to claim 2, characterized in that the critical temperature T_dValue of [50,110]℃。

6. The method for protecting the water pump according to claim 2, further comprising a step 1.2.2 of determining whether (T) is satisfied by the controller_d-2) DEG C, if yes, recording the duration t by a timer_dWhen t is_d≥6t_sAnd if so, clearing the over-temperature protection state.

7. The method for protecting the water pump according to claim 1, further comprising a step 2.3 of clearing the water shortage state when a condition one or a condition two is met:

condition one, any one of the following conditions is satisfied:

a. actual pressure P_realThe difference in instantaneous rise is greater than 0.1 bar;

b. 1 st time T_keep1Or T_keep21 hour;

c. 2 times of T continuously_keep1Or T_keep22 hours;

d. continuous 3 times of T_keep1Or T_keep24 hours;

e. continuous 4 times of T_keep1Or T_keep28 hours;

and a second condition, wherein the following conditions are satisfied:

f. the water pump is in operation;

g.P_real≥P_target。

8. the method for protecting the water pump according to claim 2, further comprising a step 1.3 of self-correcting the target pressure:

step 1.3.1, the controller records the rated power P of the water pump_rMaximum rotational speed R_maxAnd a set rotational speed R_setCalculating or measuring the actual load P_mAnd the actual rotational speed R_realAnd at intervals of unit time T_mDetecting the actual temperature T of the primary pump cavity_real；R_set≤90％×R_max；

Step 1.3.2, the controller determines T_realWhether the increase is continuously performed n times, if so, executing a step 1.3.3;

step 1.3.3, the controller determines whether P is simultaneously satisfied_m≥P_rAnd R is_real＜R_setIf not, the controller does not operate; if so, the controller adjusts the set pressure P_wlOr target pressure P_targetBy one unit pressure P_aWherein the unit pressure P_aValue of (0-1)]bar；

Step 1.3.4, return to step 1.3.1 until the set pressure P_wlOr target pressure P_targetThe use requirement is met.

9. A method for protecting a water pump according to claim 1, 2 or 8, further comprising step 1.4, freeze protection:

1) the water pump is in operation, and the controller controls the actual temperature T of the pump cavity_realAnd a stop temperatureDegree T_stopIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＞T_stopIf yes, executing step 3;

2) the water pump is in a shutdown state, and the controller controls the actual temperature T of the pump cavity_realAnd a starting temperature T_startIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＜T_startAnd when the water pump runs, the controller controls the water pump to start.

10. A method for protecting a water pump according to claim 1, 2 or 8, characterized in that it further comprises a step 1.5 of emergency: the controller judges that the water pump is in an abnormal state, starts an emergency mode, and manually adjusts the rotating speed of the water pump and/or opens and closes the water pump.

Technical Field

The invention belongs to the field of intelligent control of water pumps, and particularly relates to a protection method of a water pump.

Background

Due to the complex use environment, various operation problems can occur in the operation process of the water pump, and the existing water pump adopts a detection element to judge the abnormal state of the water pump so as to realize the automatic control of the water pump. However, the existing water pump usually depends on a pressure sensor, but the method for realizing automatic control of the water pump by solely using the pressure sensor has certain defects: because only one pressure signal is used for monitoring signals of the water pump, the starting and stopping of the water pump can be controlled only by the pressure signal, but the control accuracy is not enough in the actual use process, so that the water pump is frequently started and stopped; when the water pressure changes, the power supply voltage fluctuates or the performance of the water pump is reduced, the operating pressure of the water pump cannot reach the preset stop pressure, the water pump cannot be normally stopped, the water pump is abraded due to long-time operation, and the service life of the water pump is influenced. Therefore, it is necessary to improve the control method of the water pump to improve the control accuracy of the water pump, protect the water pump better, and reduce the influence of the operation problem on the service life of the water pump.

Disclosure of Invention

Aiming at the problem that the service life of a water pump is influenced by limitation of the existing water pump control method, the invention provides a protection method of the water pump, which effectively reduces frequent starting and stopping of the water pump and reduces influence on the service life of the water pump.

The technical scheme adopted by the invention is as follows: a protection method of a water pump comprises the following steps:

step 1, setting parameters (set pressure, set time, set temperature and the like) of a controller, collecting information detected by each detection element through the controller, and judging the state of a water pump;

step 1.1, the controller judges whether the water pressure is in a stable state or a fluctuation state by combining the water pressure sensed by the pressure sensor at the water outlet, and the specific operation is as follows: recording unit time T by a controller_sMaximum pressure P of internal water pressure_maxAnd a minimum pressure P_minAnd determining whether P is satisfied_max-P_minIf the pressure is more than 0.2bar, if not, the pressure is in a stable state, and the step 2.1 is executed; if so, the method is in a fluctuation state, and the steps are executedStep 2.2; wherein the maximum pressure P_maxAnd a minimum pressure P_minEvery unit time T_sUpdating once;

step 2, adjusting:

step 2.1, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the set pressure P_wlIf not, not recording; if yes, calculating the duration T by a timer_keep1And step 2.1.1 is executed;

step 2.1.1, the controller will last for a time T_keep1And a set time T_set1Comparing and determining whether T is satisfied_keep1≥T_set1If not, not recording; if yes, the water shortage indicator lamp is turned on, the water pump enters a water shortage protection state, and step 3 is executed;

step 2.2, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the target pressure P_{targ et}If not, not recording; if yes, calculating the duration time T by a timer_keep2And step 2.2.1 is executed;

step 2.2.1, the controller will last for a time T_keep2And a set time T_set2Comparing and determining whether T is satisfied_keep2≥T_set2If not, not recording, if yes, lighting a water shortage indicator lamp, enabling the water pump to enter a water shortage protection state, and executing the step 3;

and 3, controlling the water pump to stop running by the controller.

In the method, the actual pressure is compared with the set pressure or the target pressure, the time lasting when the actual pressure is smaller than the set pressure or the target pressure is counted by combining the timer, the water pump is prevented from being started and stopped frequently, and meanwhile, the water shortage state of the water pump is judged by adopting two modes, so that omission is effectively prevented, the control precision of the water pump is improved, and the influence on the service life of the water pump is reduced.

Further, the method also comprises the following steps:

step 1.2, sensing the actual temperature T of the pump cavity by using a temperature sensor_realThe controller will control the actual temperature T_realAnd a critical temperature T_dComparing and determining whether T is satisfied_real≥T_dIf not, the recording is not carried out, if yes, a timer is adopted to record the continuous time t_dAnd executing step 1.2.1;

step 1.2.1, the controller will last for a time t_dAnd a set time t_sComparing and judging whether t is satisfied_d≥t_sAnd if so, entering an over-temperature protection state and executing the step 3.

In actual use, there are roughly two situations that can cause the machine to be unable to stop: 1. the user target pressure is set too high, so that the machine cannot be stopped after the outlet is closed; 2. when water is used at a small flow rate, particularly when the water is fed in and runs for a period of time without pressure, air enters a pump cavity, and the machine cannot be stopped. The condition that two kinds of circumstances cause unable shut down can lead to pump chamber high temperature, if this kind of condition lasts overlength time, then causes irreversible destruction to the water pump, and then influences the water pump life-span, consequently need monitor the temperature of pump chamber. However, the water pump is controlled to stop as soon as the temperature reaches the set temperature, and the water pump is still frequently started and stopped. In the operation step 1.2 related to the method, the water pump enters an over-temperature protection state by setting the temperature and the duration time of the pump cavity, so that the condition that the water pump cannot be shut down only by detecting the actual pressure can be avoided, the abrasion caused by long-time abnormal work of the water pump is effectively reduced, and the influence on the service life of the water pump is reduced.

Further, the set pressure P_wlMaximum value of (P)_wl,maxThe conditions are satisfied as follows: p_wl,max＝P_{targ et}XG/100, wherein P_{targ et}The value of [1.0,9.0 ]]bar, G is start percentage, and the value range is [10,90 ]]. This setting guarantees that the pressure that the water pump received can not exceed its scope of bearing, can also guarantee simultaneously that the water pump can use under the requirement of difference for water pump accommodation is wider.

Further, T_set1And T_set2Value of [10,180]s, preferably 180 s. The setting is that the controller determines that the water pump is in an abnormal working state to reserve time, and the influence of frequent starting and stopping of the water pump on the water pump is effectively reduced.

Further, the critical temperature T_dValue of [50,110]Preferably 75 ℃.

Further, the method comprises a step 1.2.2 of determining by the controller whether (T) is satisfied_d-2) DEG C, if yes, recording the duration t by a timer_dWhen t is_d≥6t_sAnd if so, clearing the over-temperature protection state. t is t_sPreferably 500 ms.

Further, the method also comprises a step 2.3 of meeting the first condition or the second condition, clearing the water shortage state:

condition one, any one of the following conditions is satisfied:

a. actual pressure P_realThe difference in instantaneous rise is greater than 0.1 bar;

b. 1 st time T_keep1Or T_keep21 hour;

c. 2 times of T continuously_keep1Or T_keep22 hours;

d. continuous 3 times of T_keep1Or T_keep24 hours;

e. continuous 4 times of T_keep1Or T_keep28 hours;

and a second condition, wherein the following conditions are satisfied:

f. the water pump is in operation;

g.P_real≥P_{targ et}。

if the water shortage state is not cleared, the water pump is always in a standby state, the controller of the water pump is touched by mistake, the water pump is started by mistake, and the risk of injuring an operator by mistake is caused, so that the water shortage state needs to be cleared automatically under certain conditions.

Further, the method also comprises a step 1.3 of self-correcting the target pressure:

step 1.3.1, the controller records the rated power P of the water pump_rMaximum rotational speed R_maxAnd a set rotational speed R_setCalculating or measuring the actual load P_mAnd the actual rotational speed R_realAnd at intervals of unit time T_mDetecting the actual temperature T of the primary pump cavity_real；T_mValue of 5-20 seconds, R_set≤90％×R_max；

Step 1.3.2, the controller determines T_realWhether the increase is continuously performed n times, if so, executing a step 1.3.3; n takes a value of 1-10;

step 1.3.3, the controller determines whether P is simultaneously satisfied_m≥P_rAnd R is_real＜R_setIf not, the controller does not operate; if so, the controller adjusts the set pressure P_wlOr target pressure P_{targ et}By one unit pressure P_aWherein the unit pressure P_aValue of (0-1)]bar；

Step 1.3.4, return to step 1.3.1 until the set pressure P_wlOr target pressure P_{targ et}The use requirement is met.

During the in-service use, the user probably the lift sets up too high, leads to the water pump to work always, does not shut down, and the operation of overload can lead to the fact irreversible damage to the water pump like this, and target pressure self-correction process can make water pump automatically regulated, prevents to appear that the lift sets up the condition that the high abnormal work of water pump caused.

Further, the method also comprises a step 1.4 of antifreezing protection:

1) the water pump is in operation, and the controller controls the actual temperature T of the pump cavity_realAnd a stop temperature T_stopIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＞T_stopIf yes, executing step 3;

2) the water pump is in a shutdown state, and the controller controls the actual temperature T of the pump cavity_realAnd a starting temperature T_startIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＜T_startAnd when the water pump runs, the controller controls the water pump to start.

Therefore, the temperature of the pump cavity can be kept in a stable range through the steps, and the anti-freezing function is good.

Further, the method also comprises a step 1.5 of emergency: the controller judges that the water pump is in an abnormal state, starts an emergency mode, and manually adjusts the rotating speed of the water pump and/or opens and closes the water pump.

The water pump can encounter multiple problems in the actual use process, when a certain sensor is damaged or insensitive, the function of the water pump is in an invalid state, and the water pump enters an emergency mode by adopting emergency processing steps, so that the rotation speed of the water pump is adjustable, and the start and stop of the water pump are controllable.

The invention has the following beneficial effects: in the method, the actual pressure is compared with the set pressure or the target pressure, the time lasting when the actual pressure is smaller than the set pressure or the target pressure is counted by combining the timer, the water pump is prevented from being started and stopped frequently, and meanwhile, the water shortage state of the water pump is judged by adopting two modes, so that omission is effectively prevented, the control precision of the water pump is improved, and the influence on the service life of the water pump is reduced.

Drawings

FIG. 1 is a flow chart of the operation of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention are explained and explained below with reference to the drawings of the present invention, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present invention.

The protection method of the water pump of the embodiment, as shown in fig. 1, includes the following steps:

step 1, setting parameters (set pressure, set time, set temperature and the like) of a controller, collecting information detected by each detection element through the controller, and judging the state of a water pump;

step 1.1, the controller judges whether the water pressure is in a stable state or a fluctuation state by combining the water pressure sensed by the pressure sensor at the water outlet, and the specific operation is as follows: recording unit time T by a controller_sMaximum pressure P of internal water pressure_maxAnd a minimum pressure P_minAnd determining whether P is satisfied_max-P_minIf the pressure is more than 0.2bar, if not, the pressure is in a stable state, and the step 2.1 is executed; if yes, the device is in a fluctuation state, and then step 2.2 is executed; wherein the maximum pressure P_maxAnd a minimum pressure P_minEvery unit time T_sUpdating once;

step 1.2, sensing the actual temperature T of the pump cavity by using a temperature sensor_realThe controller will control the actual temperature T_realAnd a critical temperature T_dComparing and determining whether T is satisfied_real≥T_dIf not, the recording is not carried out, if yes, a timer is adopted to record the continuous time t_dAnd executing step 1.2.1; critical temperature T_dValue of [50,110]Preferably 75 ℃ in this example.

Step 1.2.1, the controller will last for a time t_dAnd a set time t_sComparing and judging whether t is satisfied_d≥t_sAnd if so, entering an over-temperature protection state and executing the step 3. t is t_sPreferably 500 ms.

Step 1.2.2, determining whether (T) is satisfied by the controller_d-2) deg.C (73 deg.C), if so, recording the duration t with a timer_dWhen t is_d≥6t_s(i.e., 3 seconds), the over-temperature protection state is cleared.

Step 1.3, self-correcting the target pressure:

step 1.3.1, the controller records the rated power P of the water pump_rMaximum rotational speed R_maxAnd a set rotational speed R_setCalculating or measuring the actual load P_mAnd the actual rotational speed R_realAnd at intervals of unit time T_mDetecting the actual temperature T of the primary pump cavity_real；T_mValue of 5-20 seconds, R_set≤90％×R_max(ii) a For example, model TDC250S, rated power P_r310W, maximum rotation speed R_maxIs 3000 rpm/min;

step 1.3.2, the controller determines T_realWhether the increase is continuously performed n times, if so, executing a step 1.3.3; in this embodiment, n takes a value of 5;

step 1.3.3, the controller determines whether P is simultaneously satisfied_mNot less than 310W and R_realIf the speed is less than 2700rpm/min, the controller does not operate; if so, the controller adjusts the set pressure P_wlOr target pressure P_{targ et}By one unit pressure P_aIn the present embodiment, the unit pressure P_aTaking 0.5 bar;

step 1.3.4, return to step 1.3.1 until the set pressure P_wlOr target pressure P_{targ et}The use requirement is met. During the in-service use, the user probably the lift sets up too high, leads to the water pump to work always, does not shut down, and the operation of overload can lead to the fact irreversible damage to the water pump like this, and target pressure self-correction process can make water pump automatically regulated, prevents to appear that the lift sets up the condition that the high abnormal work of water pump caused.

Step 1.4, antifreezing protection:

1) the water pump is in operation, and the controller controls the actual temperature T of the pump cavity_realAnd a stop temperature T_stopIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＞T_stopIf yes, executing step 3;

2) the water pump is in a shutdown state, and the controller controls the actual temperature T of the pump cavity_realAnd a starting temperature T_startIn comparison, when the controller determines that the actual temperature T of the pump chamber is satisfied_real＜T_startAnd when the water pump runs, the controller controls the water pump to start.

Step 1.5, emergency step: the controller judges that the water pump is in an abnormal state, starts an emergency mode, and manually adjusts the rotating speed of the water pump and/or opens and closes the water pump.

Step 2, adjusting:

step 2.1, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the set pressure P_wlIf not, not recording; if yes, calculating the duration T by a timer_keep1And step 2.1.1 is executed; set pressure P_wlMaximum value of (P)_wl,maxThe conditions are satisfied as follows: p_wl,max＝P_{targ et}XG/100, wherein P_{targ et}The value of [1.0,9.0 ]]bar, G is start percentage, and the value range is [10,90 ]]. This setting guarantees that the pressure that the water pump received can not exceed its scope of bearing, can also guarantee simultaneously that the water pump can use under the requirement of difference for water pump accommodation is wider.

Step 2.1.1, the controller will last for a time T_keep1And a set time T_set1Comparing and makingDetermining whether T is satisfied_keep1≥T_set1If not, not recording; if yes, the water shortage indicator lamp is turned on, the water pump enters a water shortage protection state, and step 3 is executed;

step 2.2, the controller is used for judging the actual pressure P in the water pump_realWhether or not less than the target pressure P_{targ et}If not, not recording; if yes, calculating the duration time T by a timer_keep2And step 2.2.1 is executed;

step 2.2.1, the controller will last for a time T_keep2And a set time T_set2Comparing and determining whether T is satisfied_keep2≥T_set2If not, not recording, if yes, lighting a water shortage indicator lamp, enabling the water pump to enter a water shortage protection state, and executing the step 3;

T_set1and T_set2Value of [10,180]s, preferably 180 s. The setting is that the controller determines that the water pump is in an abnormal working state to reserve time, and the influence of frequent starting and stopping of the water pump on the water pump is effectively reduced.

And 2.3, meeting the first condition or the second condition, and clearing the water shortage state:

condition one, any one of the following conditions is satisfied:

a. actual pressure P_realThe difference in instantaneous rise is greater than 0.1 bar;

b. 1 st time T_keep1Or T_keep21 hour;

c. 2 times of T continuously_keep1Or T_keep22 hours;

d. continuous 3 times of T_keep1Or T_keep24 hours;

e. continuous 4 times of T_keep1Or T_keep28 hours;

and a second condition, wherein the following conditions are satisfied:

f. the water pump is in operation;

g.P_real≥P_{targ et}。

and 3, controlling the water pump to stop running by the controller.

In the method, the actual pressure is compared with the set pressure or the target pressure, the time lasting when the actual pressure is smaller than the set pressure or the target pressure is counted by combining the timer, the water pump is prevented from being started and stopped frequently, and meanwhile, the water shortage state of the water pump is judged by adopting two modes, so that omission is effectively prevented, the control precision of the water pump is improved, and the influence on the service life of the water pump is reduced.

In actual use, there are roughly two situations that can cause the machine to be unable to stop: 1. the user target pressure is set too high, so that the machine cannot be stopped after the outlet is closed; 2. when water is used at a small flow rate, particularly when the water is fed in and runs for a period of time without pressure, air enters a pump cavity, and the machine cannot be stopped. The condition that two kinds of circumstances cause unable shut down can lead to pump chamber high temperature, if this kind of condition lasts overlength time, then causes irreversible destruction to the water pump, and then influences the water pump life-span, consequently need monitor the temperature of pump chamber. However, the water pump is controlled to stop as soon as the temperature reaches the set temperature, and the water pump is still frequently started and stopped. In the operation step 1.2 related to the method, the water pump enters an over-temperature protection state by setting the temperature and the duration time of the pump cavity, so that the condition that the water pump cannot be shut down only by detecting the actual pressure can be avoided, the abrasion caused by long-time abnormal work of the water pump is effectively reduced, and the influence on the service life of the water pump is reduced.

While the invention has been described with reference to specific embodiments, the scope of the invention is not limited thereto, and those skilled in the art will appreciate that the invention includes, but is not limited to, the accompanying drawings and the description of the embodiments above. Any modification which does not depart from the functional and structural principles of the present invention is intended to be included within the scope of the claims.