WO2009157026A1

WO2009157026A1 - Equipment for filling with liquid a diaphragm pump chamber

Info

Publication number: WO2009157026A1
Application number: PCT/IT2008/000434
Authority: WO
Inventors: Luciano Manara; Giorgio Vinciguerra; Alberto Randi
Original assignee: Peroni Pompe S.P.A
Priority date: 2008-06-27
Filing date: 2008-06-27
Publication date: 2009-12-30

Abstract

An equipment (100) for filling a chamber (4) of a diaphragm pump (1) with liquid comprises a first pump (104) for feeding liquid to the chamber (4), an electric valve (107) for controlling the flow of liquid fed by the first pump (104), a second pump (110) for sucking liquid from the chamber (4), an electric valve (113) for controlling the flow of liquid sucked by the second pump (110), an electric motor (114) for the actuation of the pumps (104, 110), a pressure sensor (115) capable of detecting the pressure of the liquid leaving the chamber, and control means (116) capable of closing the first electric valve (107) on detection of a first operative state of the equipment (100) and capable of closing the second electric valve (113) and switching off the electric motor (114) on detection of a second operative state of the equipment (100).

Description

Title: "Equipment for filling with liquid a diaphragm pump chamber"

DESCRIPTION

The present invention relates to an equipment for filling a chamber of a diaphragm pump with liquid. Diaphragm pumps are known in the prior art. A diaphragm pump comprises a process chamber in which a process liquid, for example water, is sucked from outside and then pumped towards the outside by the effect of a cyclical pressure variation in the aforesaid chamber and of the consequent opening and alternate closing of two non-return valves which separate the process chamber from the outside.

In a diaphragm pump, the pressure difference required to impart the motion to the process fluid is brought about by the displacement of diaphragm means which separate the process chamber from a control chamber. It should be noted that the diaphragm means may comprise a single diaphragm or a number of diaphragms separated from one another by an interdiaphragm chamber.

The displacement of the diaphragm means is itself controlled by a movable member, typically a piston, by means of a stem rigidly secured to both, or also by means of a control liquid which flows in the control chamber.

Before starting-up, for the operation of the diaphragm pump it is necessary to fill the control chamber, like the interdiaphragm chamber, with a liquid. Generally, the liquid used to fill the control chamber is identical to that used to fill the interdiaphragm chamber.

In the prior art, the filling of the chambers of a pump is carried out manually by an operator who causes the liquid, present in a container, to flow into the individual chambers until these are completely filled. An extremely critical aspect of the filling of such chambers lies in the formation of air-bubbles. When such bubbles have a not inconsiderable volume, they may cause a malfunction of the pump. In this regard it should be noted that such bubbles will be continually compressed and decompressed during the pumping phase, with a consequent loss of volumetric efficiency of the pump. Moreover, such bubbles could deform the diaphragm means in an unhomogeneous manner, even causing breakage thereof in an extreme case.

From what has been disclosed above, it comes out that there is a need to provide an equipment which makes it possible to fill a chamber of a diaphragm pump with liquid while avoiding the formation of air-bubbles inside the chamber itself.

It is therefore an aim of the invention to propose an equipment for filling a chamber of a diaphragm pump with liquid which has structural and functional characteristics such as to fulfil the aforesaid requirements and at the same time to remedy the drawbacks encountered with reference to the prior art.

This aim is achieved by means of an equipment for filling a chamber of a diaphragm pump with liquid according to claim 1. Further characteristics and advantages of the equipment according to the present invention will become clear from the following description of a preferred exemplary embodiment, provided by way of non-limiting example with reference to the appended drawings, in which: - Figure 1 shows a diagram of an equipment for filling a chamber of a diaphragm pump with liquid according to the present invention,

Figure 2 shows a sectional view of a detail of a reciprocating diaphragm pump. With reference to the appended drawings, the reference 100 indicates overall an equipment for filling a chamber of a diaphragm pump with liquid.

In particular, in the continuation of the present description, reference will be made, without implying any limitation, to the reciprocating diaphragm pump shown in Figure 2.

It should also be noted that the liquid may be oil or a mixture of glycols.

The pump 1 comprises a stationary base body 10, a plurality of pistons which extend along respective longitudinal axes, indicated by X-X and parallel to one another, and transmission means for transmitting the motion (not shown in the drawings) , for example a drive shaft and a connecting-rod/crank system which transmit the motion to the pistons.

In order to set the drive shaft in motion, the pump 1 comprises, in a manner which is known per se, suitable actuating means (not shown in the drawings) .

Each piston 2 is housed so as to be able to slide in a corresponding cylinder 3, which is disposed adjacent to the cylinders of the other pistons and defines a portion of a control chamber 4.

A process chamber 5 is located in the hydraulic part

6 of the pump 1. The process chamber 5 is intended to communicate, by means of the interposition of intake valve

11 and delivery valve 12, with corresponding intake pipe 8 and delivery pipe 9.

The process chamber 5 and the control chamber 4 are separated from each other by diaphragm means 7 to which the motion of the piston 2 inside the cylinder 3 is transmitted via the liquid present in the control chamber

4.

According to one embodiment, the diaphragm means 7 comprise a first diaphragm 7a and a second diaphragm 7b that are parallel to and separate from one another so as to define an interdiaphragm chamber 15. Typically, the thickness of the film of interdiaphragm liquid which separates the two diaphragms 7a, 7b is of the order of a millimetre. A description is given below of the equipment 100 of the present invention with reference to the control chamber 4 of the pump 1.

The equipment 100 comprises a first inlet 101 for connection to a source of liquid 102, a first outlet 103 for connection to the inlet 4a of the chamber 4, a first pump 104, hereinafter a feed pump, having an intake 105 connected to the first inlet 101 for sucking the liquid from the source of liquid 102 and a delivery 106 connected to the first outlet 103 for feeding the control chamber 4. A first electric valve 107 is interposed between the delivery 106 of the feed pump 104 and the first outlet 103 for controlling the flow of liquid fed by the feed pump 104 to the chamber 4.

Bypass means 123 connect the delivery 106 of the feed pump 104 to the intake 105 thereof. In particular, the bypass means 123 comprise a bypass pipe 124 and a nonreturn valve 125 which intercepts the flow of liquid from the delivery 106 to the intake 105.

The equipment 100 further comprises a second inlet 108 for connection to the outlet 4b of the chamber 4, a second outlet 109 for discharging the liquid and a second pump 110, hereinafter a discharge pump, having an intake 111 connected to the second inlet 108 for sucking liquid from the chamber 4 and a delivery 112 connected to the second outlet 109 for the discharge of liquid.

For the connection of the second inlet 108 to the outlet 4b of the chamber 4, as for the connection of the first outlet 103 to the inlet 4a of the chamber 4, it is possible to use flexible tubes (not shown in the drawing) or other pipes or systems suitable for that purpose. A second electric valve 113 is interposed between the second inlet 108 and the intake 111 of the discharge pump 110 for controlling the flow of liquid sucked by the discharge pump 110. The equipment 100 likewise comprises an electric motor 114 connected to the pumps 104, 110 for the actuation of said pumps, and a pressure sensor 115 capable of detecting the pressure of the liquid at the first inlet 108. The equipment 100 further comprises control means 116 connected to the first electric valve 107, for closing the first electric valve 107 on detection of a first operative state of the equipment 100, and connected to the pressure sensor 115, to the electric motor 114 and to the second electric valve 113, for closing the second electric valve 113 and switching off the electric motor 114 on detection of a second operative state of the equipment 100.

The control means 116 may comprise, for example, a programmable electronic card. According to one form of embodiment, the control means 116 are capable of closing the second electric valve 113 and switching off the electric motor 114 on detection of the second operative state of the equipment 100, following the detection of the first operative state. In particular, the control means 116 effect the closure of the first electric valve 107 when the chamber 4 is considered to be filled with liquid and devoid of air bubbles. The closure of the first electric valve 107 interrupts the feeding of liquid to the discharge pump 110, allowing it to produce a depression inside the chamber 4. In this case, the depression which is produced in the chamber 4, besides rendering the absence of air bubbles in the chamber 4 itself even more certain, effects the correct positioning of the diaphragm means 7 independently of the position of the piston 2 so as to permit correct functioning of the pump 1.

On closure of the first electric valve 107, the feed pump 104 continues to pump liquid towards the bypass pipe 124, increasing the pressure thereof up to a value such as to open the non-return valve 125, calibrated to a predefined value, for example two bars relative. In this situation, the liquid fed by the feed pump 104 also flows via the bypass pipe 124 to the intake 105 so as to create a closed circuit. On reaching a predefined level of depression inside the chamber 4, the control means 116 close the second electric valve 113 in order to maintain the liquid inside the chamber 4 at the predefined level of depression and they therefore switch off the electric motor 114. According to one form of embodiment, the control means 116 are capable of measuring the difference in mass delivery M_out-Min of liquid between the inlet 4a of the chamber 4 and the outlet 4b thereof for the purpose of ascertaining the absence of air bubbles within the chamber 4. In the specific case, the control means 116 are capable of measuring the difference in mass delivery M_out-Min of liquid between the first outlet 103 and the second inlet 108 in order to close the first electric valve 107 so as to stop the delivery of liquid to the chamber 4 and interrupt the feeding of liquid to the discharge pump 110 when the difference is close to zero.

In this case, the control means 116 may comprise two mass delivery meters located at the first outlet 103 and at the second inlet 108, and a control centre capable of comparing the mass delivery values provided by the two delivery meters in order to actuate the closure of the electric valve 107.

According to an alternative form of embodiment, the control means 116 are capable of measuring the volume V_out of liquid discharged from the second outlet 109 in order to close the first electric valve 107 when that discharged volume exceeds a predefined volume threshold V_th-

The volume of liquid discharged may be measured by means of a delivery sensor positioned at the second outlet 109.

Alternatively, as shown in Figure 1, the second outlet 109 may be connected to a discharge tank 117. In this case, the control means 116 are capable of measuring the volume of liquid V_out discharged into the discharge tank 117 in order to close the first electric valve 107 when that discharged volume exceeds the predefined volume threshold V_th- In the case in question, a level sensor 118 associated with the discharge tank 117 and connected to the control means 116 may be provided. Advantageously, the discharge tank 117 has an electric valve 122 which permits the discharge of the liquid once the level of positioning of the level sensor 118 is reached. For example, the electric valve 122 may place the discharge tank 117 in communication with the source of liquid 102 so as to form a closed recirculation circuit and re-use the same liquid for the filling of another chamber of the same pump or of a different pump.

According to one form of embodiment, the control means 116 are capable of switching off the electric motor 114 in order to stop the two pumps 104, 110, when the pressure P measured by the pressure sensor 115 reaches a predefined pressure threshold Pth-

In particular, the value of the pressure threshold P_th is such as to produce a depression in the chamber 4 of the pump 1. For example, the pressure threshold value P_th may be below -0.1 bar relative, preferably -0.2 bar relative.

The equipment 100 of the present invention may also be used for filling further chambers of a diaphragm pump with liquid, such as, for example, the interdiaphragm chamber 15. It should be noted that the equipment 100 may also be used for filling more than two chambers and also more pumps.

In particular, the equipment 100 may comprise a third outlet 119 for connection to the inlet 15a of the interdiaphragm chamber 15, and a third inlet 120 for connection to the outlet 15b of the interdiaphragm chamber

15.

In this case, the first electric valve 107 is capable of connecting the delivery 106 of the feed pump 104 alternatively to the first outlet 103 or to the third outlet 119, while the second electric valve 113 is capable of connecting the intake 111 of the discharge pump 110 alternatively to the second inlet 108 or to the third inlet 120. The equipment 100 will also comprise a second pressure sensor 121 capable of detecting the pressure of the liquid at the third inlet 120. In this case, since the two diaphragms 7a, 7b must approach each other in such a way as to leave only a thin layer of liquid between them, the pressure threshold value Pth is typically -0.8 bar relative.

It should be noted that, during the operation of the pump 1, the equipment 100 makes it possible to avoid the filling of the chamber 4 and to carry out only the discharge of the liquid from the chamber 4, after the closure of the electric valve 107, in order to restore the depression lost during operation.

According to one form of embodiment, it is possible to provide a plurality of valves Vl, V2, V3, V4 located at the inlet and at the outlet of each chamber. In particular, in Figure 2, the valves Vl and V2 are located respectively at the inlet 4a and at the outlet 4b of the control chamber 4, while the valves V3 and V4 are located respectively at the inlet 15a and at the outlet 15b of the interdiaphragm chamber 15. The valves V1-V4 must be open at the start of the complete cycle of filling the chambers, and closed at the end thereof. The closure operation must be carried out before detaching the tubes connecting the equipment to the chambers, so as to avoid losing the depression obtained. Alternatively, it is possible to use quick-fixing connections with non-return valves.

As may be appreciated from what has been described, the equipment for filling a chamber of a diaphragm pump with liquid according to the invention makes it possible to fulfil the requirements mentioned in the introduction of the present description, and to remedy the drawbacks of the diaphragm pumps of the prior art.

Naturally, for the purpose of fulfilling contingent and specific requirements, a person skilled in the art may apply to the equipment according to the invention described above, numerous modifications and variants, all being included within the scope of protection of the invention as defined by the following claims.

Claims

1. Equipment (100) for filling a chamber (4) of a diaphragm pump (1) with liquid, said equipment comprising: a first inlet (101) for connection to a source of liquid (102), a first outlet (103) for connection to an inlet (4a) of the chamber (4), a first pump (104) having an intake (105) connected to said first inlet (101) for sucking liquid from the source of liquid (102), and a delivery (106) connected to said first outlet (103) for feeding liquid to the chamber

(4), a first electric valve (107) interposed between the delivery (106) of the first pump (104) and the first outlet (103) for controlling the flow of liquid fed by the first pump (104) , bypass means (123) for connecting the delivery (106) and the intake (105) of the first pump (104), - a second inlet (108) for connection to an outlet (4b) of the chamber (4), a second outlet (109) for the discharge of liquid, a second pump (110) having an intake (111) connected to said second inlet (108) for sucking liquid from the chamber (4), and a delivery (112) connected to said second outlet (109) for the discharge of the liquid, a second electric valve (113) interposed between said second inlet (108) and the intake (111) of the second pump (110) for controlling the flow of liquid sucked by the second pump (110), an electric motor (114) connected to said first pump (104) and said second pump (110) for the actuation of said pumps (104, 110), a pressure sensor (115) capable of detecting the pressure of the liquid at the second inlet (108), control means (116) connected to the first electric valve (107) for closing the first electric valve (107) on detection of a first operative state of the equipment

(100), and connected to the pressure sensor (115), to the electric motor (114) and to the second electric valve

(113) for closing the second electric valve (113) and switch off the electric motor (114) on detection of a second operative state of the equipment (100) .

2. Equipment (100) according to claim 1, wherein said control means (116) are capable of closing the second electric valve (113) and switching off the electric motor (104) on detection of the second operative state of the equipment (100) , following the detection of the first operative state.

3. Equipment (100) according to claim 1 or 2, wherein said control means (116) are capable of measuring the difference in mass delivery of liquid between the first outlet (103) and the second inlet (108) for closing the first electric valve (107) when said measured difference is close to the zero value.

4. Equipment (100) according to claim 1, wherein said control means (116) are capable of measuring the volume of liquid discharged from said second outlet (109) for closing the first electric valve (107) when said discharged volume exceeds a predefined volume threshold.

5. Equipment (100) according to claim 1, wherein said second outlet (105) is connected to a discharge tank (117), said control means (116) being capable of measuring the volume of liquid discharged into said discharge tank (117) for closing the first electric valve (107) when said discharged volume exceeds a predefined volume threshold.

6. Equipment (100) according to claim 5, wherein said discharge tank (117) comprises a level sensor (118) connected to said control means (116) .

7. Equipment (100) according to any one of claims 1 to 6, wherein said control means (116) are capable of switching off the electric motor (114) for stopping said pumps (104,110), when the pressure measured by the pressure sensor (115) reaches a predefined pressure threshold.

8. Equipment (100) according to claim 7, wherein said predefined pressure threshold is such as to produce a depression in the chamber (4) of the pump (1) .

9. Equipment (100) according to any one of claims 1 to 8, wherein said chamber (4) is a control chamber of a diaphragm pump (1) .

10. Equipment (100) according to any one of claims 1 to 9, comprising: a third outlet (119) for connection to an inlet (15a) of a second chamber (15), a third inlet (120) for connection to an outlet (15b) of the second chamber (15), wherein said first electric valve (107) is capable of connecting the delivery (106) of the first pump (104) alternatively to the first outlet (103) or to the third outlet (119), and said second electric valve (113) is capable of connecting the intake (111) of the second pump (110) alternatively to the second inlet (108) or to the third inlet (120) .

11. Equipment (100) according to claim 10, comprising a second pressure sensor (121) connected to said control means (116) and capable of detecting the pressure of the liquid at the third inlet (120).

12. Equipment (100) according to claim 10 or 11, wherein said second chamber (15) is an interdiaphragm chamber of a diaphragm pump (1) .