The present invention pertains to a pressure packing for a reciprocating piston compressor having a buffer gas barrier at a low-pressure side of the pressure packing and a number of sealing rings at an opposite high-pressure side of the pressure packing, whereas a vent volume is provided in the pressure packing between the buffer gas barrier and the last sealing ring before the buffer gas barrier with a vent line being connected to the vent volume, whereas a buffer gas volume is provided in the buffer gas barrier that is connected to a buffer gas feeding line, whereas, during operation of the pressure packing, a buffer gas with buffer gas pressure is supplied into the buffer gas volume via the buffer gas feeding line with the buffer gas pressure being higher than the vent pressure in the vent volume. The invention pertains also to a method for operating such a pressure packing for a reciprocating piston compressor and to a reciprocating piston compressor with such a pressure packing.
Reciprocating piston compressors for compressing a process gas are well known and are used in many applications and for different process gases. A reciprocating piston compressor comprises at least one cylinder with at least one suction valve and at least one discharge valve for the process gas exchange. In the cylinder a piston reciprocates back and forth driven by a piston rod. A pressure packing surrounds the piston rod to seal the gas in the cylinder. A pressure packing comprises a packing case made up of several adjacent (in the axial direction of the packing case/piston rod) packing cups with sealing rings and/or wiper rings being arranged in the cups. The piston rod is connected to a crosshead which in turn is connected to a crank of a crankshaft. The crosshead translates the rotating movement of the crank into the reciprocating movement of the piston rod. The crank shaft is located in a crankcase. Between the crankcase and the cylinder (or the pressure packing) there is often arranged a distance piece in which the piston rod and sometimes also the crosshead or at least a part of the crosshead reciprocates. Between the distance piece and the crank case there can also be arranged an additional partition packing around the piston rod. In operation of the reciprocating piston compressor there is always a process gas leakage through the pressure packing or around the pressure packing as the pressure packing is never absolutely gastight. Such a process gas leakage is undesirable, not only because of the resulting process gas loss.
Depending on the process gas, process gas leakage can be problematic, especially when toxic, hazardous, combustible or explosive process gas is used.
Any process gas emission into the surroundings of the compressor is undesirable. There are even statutory limitations for such gas emissions that require avoidance of gas emissions into the surroundings. This is especially true if toxic or hazardous process gas is used. In case of combustible or explosive process gas there is additional risk of gas accumulating in the compressor, e.g. in the distance piece or crankcase, that need to be avoided. Gas leakage into the crankcase can also contaminate the crankcase lube oil detrimentally affecting the operation of the compressor. When using a distance the process gas leakage from the cylinder through or around the pressure packing would not directly enter the crankcase but would enter the distance piece first. Leakage of process gas into the crankcase can be reduced in that way but not completely avoided.
It is therefore a general desire in a reciprocating piston compressor to confine and collect process gas leakage from the piston rod pressure packing and to carry the leakage to a safe location away from the compressor.
To achieve this, it is already known to provide a vent line in the pressure packing which provides for connection from a location inside the pressure packing to a location on the exterior of the pressure packing. Connection of additional conduits to the external vent line exit from the pressure packing allows for directing the process gas leakage to a controlled point external to the compressor itself. The vent line is connected to a vent volume, e.g. arranged in a vent cup or between two adjacent sealing rings, in the pressure packing. Process gas leaking into the pressure packing is directed from the vent volume into the vent line.
A vent line in the pressure packing does however not totally prevent process gas leakage, as gas leakage can also occur between adjacent cups or even around the pressure packing.
To further reduce process gas leakage, it also known to use pressurised buffer gas, such as Nitrogen or any other inert or unproblematic gas, in the pressure packing and/or in the distance piece. The pressure of the buffer gas is set to be higher than the pressure of the process gas at the respective location, for example at the low-pressure side of the pressure packing. The buffer gas is fed between two adjacent sealing rings of the pressure packing and forms a gas barrier for the process gas in the pressure packing. In this case, only buffer gas exits the pressure packing. If a vent line is used in the pressure packing, the internal starting point of the vent line in the pressure packing is located between the sealing rings at the high-pressure side of the packing and the gas barrier. In this case, buffer gas would also be removed via the vent line. In the vent line there would be a mixture of buffer gas and process gas. Also, in the partition packing buffer gas could be used to form a gas barrier to reduce the risk of process gas leakage from the distance piece into the crankcase. A gas barrier in the pressure packing or partition packing does however not prevent process gas leakage between cups or around the packing itself. Therefore, it is sometimes also provided to purge the distance piece with purge gas. As purge gas, the same gas is usually used that is used as buffer gas. This means the purge gas is fed into the distance piece and a mixture of purge gas with any process gas leakage is drained from the distance piece. Use of purge gas fed directly into the distance piece works on the principle of diluting and sweeping away process gas leakage rather than to block flow of process gas leakage on the basis of pressure gradient (as in the buffer gas barrier). However, adequate pressure of the purge gas supply must be maintained to assure positive flow into the distance piece.
It is therefore also known to use so called purge panels that provide the required buffer gas for the reciprocating piston compressor. The purge panel comprises the necessary instrumentation, like valves, flow regulators, measurement instruments, etc., needed for providing the buffer gas. It is especially important to be able to control the pressure of the buffer gas, which has to be higher than the gas pressure of the gas to be sealed or has to be high enough to allow purging of the distance piece. Usually, it is requested that the buffer gas pressure is at least 1 bar higher than the gas at the respective location of usage of the buffer gas. For certain locations, for example in the distance piece or the partition packing, the buffer gas pressure could be set statically to a certain pressure. Usage of a buffer gas in a pressure packing with a vent line requires however a dynamically changing buffer gas pressure as the pressure in the packing, and especially in the vent line, usually varies dynamically (depending on the backpressure existing in the vent line, for example if connected to a flare system for flaring leaking process gas). Therefore, the pressure in the vent line is often used as pilot pressure to control a pressure regulator in the purge panel to set the buffer gas pressure.
In many instances, the vent line connected to the vent volume of the pressure packing would be routed through the panel itself in order to be able to use the vent line pressure as pilot pressure for the differential pressure regulator. It is also known to branch off a pilot line from the vent line and to lead the pilot line into the purge panel. This creates however several issues. On lubricated compressors, there is the necessity to install a liquid/gaseous separator for the vent line or pilot line between the compressor and the purge panel, causing extra cost. Another issue is the pressure drop in the vent line caused by flow of gas in the line. In operation of the compressor, the gas leakage from the pressure packing increases over time due to wear of the sealing rings in the packing. This causes the gas flow in the vent line to increase over time which corresponds to an increased pressure drop in the vent line over time. This variable (increasing) pressure drop means that the purge panel reads the wrong pilot pressure from the vent line for controlling the pressure regulator, and therefore the performance of the purge panel degrades over time. This can cause increased emissions of process gas from the compressor, which has to be avoided.
It is therefore an object of the present invention to provide a pressure packing with a vent volume and a buffer gas barrier for a reciprocating piston compressor that avoids the above-mentioned problems.
This object is achieved by providing a sensing line that is connected at a first end to the vent volume in the pressure packing with an opposite second end of the sensing line being closed, so that there is no gas flow in the sensing line, and by connecting a pressure regulator to the buffer gas feeding line for setting the buffer gas pressure in the buffer gas feeding line, whereas, during operation of the pressure packing, the pressure in the sensing line is used as pilot pressure for the pressure regulator for setting the buffer gas pressure. The sensing line is completely separated from the vent line by which process gas leakage is carried away from the pressure packing. As the sensing line is closed on the end opposite the vent volume and separated from the vent line, there cannot be a gas flow in the sensing line and consequently no pressure drop in the sensing line due to gas flow. This ensures correct readings of the vent pressure that is used as pilot pressure for controlling the pressure regulator for setting the buffer gas pressure for the pressure packing. The buffer gas pressure is preferably set a given differential pressure higher than the pilot pressure (vent pressure).
In an advantageous embodiment, a differential pressure control valve with a pilot input is used as pressure regulator, whereas the sensing sense line is connected to the pilot pressure input of the differential pressure control valve.
The sensing line is advantageously arranged in an upper part of the pressure packing. This, together with the fact that the sensing line is a static line without gas flow, reduces or even eliminates the amount of lubricant oil that can possibly be carried with the sensing line. Therefore, no liquid gas separator is required in the sensing line upstream of the pressure regulator, which reduces the overall costs and equipment complexity.
Using a purge panel with the pressure regulator being arranged in a gas line of the purge panel that connects a buffer gas inlet and a buffer gas outlet of the purge panel, whereas the buffer gas outlet is connected to the buffer gas feeding line and the buffer gas inlet is provided for connecting a buffer gas supply to the purge panel and whereas a sensing sense line inlet is arranged on the purge panel that is connected to the sensing sense line, allows for a neat arrangement of all required instrumentation for providing the buffer gas.
If a purge panel with an enclosure is used, it is especially advantageous to provide a pneumatic booster relay outside of the enclosure with the sensing line being connected to a pilot port of the pneumatic booster relay. In that way it can be ensured that the process gas in the sensing line cannot leak into the enclosure in case of malfunction, which would be hazard.
The present invention is described in greater detail in the following with reference to
In a crankcase 7 a crank shaft 8 having a crank 9 is arranged. The crank shaft 8 is driven by a drive (not shown in
A pressure packing 14 is provided around the reciprocating piston rod 12 for sealing the process gas PG in cylinder 2 against other components of the piston compressor 1. The pressure packing 14 can be arranged in the cylinder head 3 or in any other component of the piston compressor 1.
A pressure packing 14 of a reciprocating piston compressor 1 is well-known and comprises several packing cups 15—in
At the low-pressure side LP of the pressure packing 14, i.e. at the side of the packing 14 facing away from the cylinder 2 when in use, a buffer gas barrier 18 is provided by providing a buffer gas volume 19 in the pressure packing 14 into which a buffer gas BG can be fed via a buffer gas feeding line 20. At least a part of the buffer gas feeding line 20 can be arranged in the pressure packing 14. The buffer gas volume 19 is sealed-off against other parts of the pressure packing 14, e.g. by additional sealing rings 21a, 21b, so that the buffer gas volume 19 can be pressurised by means of pressurised buffer gas BG. The exemplary buffer gas volume 19 in
As buffer gas BG an inert gas, like nitrogen, could be used.
The buffer gas volume 19, or the buffer gas BG in the buffer gas volume 19, prevents (or at least reduces) leakage of process gas PG from the high-pressure side HP, e.g. the cylinder 2 side, through the pressure packing 14 to the low-pressure side LP. To this end, the buffer gas pressure pB in the buffer gas volume 19 is set to be higher than the acting pressure in the pressure packing 14 at the location before (in direction of the high-pressure side HP) the buffer gas volume 19.
Between the buffer gas volume 19 and the primary sealing rings 16a, 16b, 16c a vent volume 24 is formed that is connected to a vent line 25 of the pressure packing 14. The buffer gas volume 19 is sealed against the vent volume 24, e.g. by sealing ring 21a of the buffer gas barrier 18 as in
The vent volume 24 and the vent line 25 serve to drain any process gas PG leakage through the pressure packing 14, i.e. through the sealing rings 16a, 16b, 16c.
In some cases, the vent line 25 also drains cylinder 4 and/or piston rod 12 lubricant oil that is for example transported with the process gas PG. The vent line 25 is therefore often arranged on a lower (in the direction of gravity) part of the pressure packing 14, as shown in
An additional wiper ring 23 could be arranged in the pressure packing 14 at the low-pressure side LP of the pressure packing 14 as indicated in
In use of the pressure packing 14 in the compressor 1, the low-pressure side LP of the pressure packing 14 is at the side of the crankcase 7 and the high-pressure side HP is facing the cylinder 2.
The working principle of the pressure packing 14 with buffer gas barrier 18 and vent line 25 is well-known and is explained in
In the embodiment of
Between the distance piece 13 (13a) and the crankcase 7 there can be a partition packing 30 in the partition wall between the distance piece 13 (13a) and the crank case 7. Also between two adjacent distance pieces 13, 13a an intermediate packing 31 could be arranged. The partition packing 30 and/or the intermediate packing 31 can be designed similar to the pressure packing 14, i.e. with at least one cup with at least one sealing ring and/or wiper ring being arranged therein.
In an intermediate packing 31, and/or a partition packing 30, an additional buffer gas barrier 18 could be provided that could be implemented as described above for the buffer gas barrier 18 of the pressure packing 14. In an intermediate packing 31, and/or a partition packing 30, there would however usually no vent line 25. The pressurised buffer gas BG fed into the buffer gas barrier 18 of the intermediate packing 31 via intermediate packing buffer gas line 32b (indicated in
The buffer gas pressure of the buffer gas for the intermediate packing 31 or the partition packing 30 is set to be higher, preferably at least 1 bar higher, than the pressure in the adjacent distance piece 13, 13a or crankcase 7, usually atmospheric pressure patm. As the pressure in the distance piece 13, 13a or crankcase 7 does usually not change, the buffer gas pressure could be set statically to a required value.
A distance piece 13 (13a) could optionally also be purged with buffer gas BG, as shown in
From the above explanations it is obvious that buffer gas BG of different pressures could be required for operating a reciprocating piston compressor 1. According to the invention, the reciprocating piston compressor 1 has at least a pressure packing 14 with a buffer gas barrier 18. Hence, at least buffer gas BG with a buffer gas pressure pB that is always higher than the expected or existing vent pressure pV is required. In a possible embodiment, the vent pressure pV is dynamically changing over time. In such an embodiment, the buffer gas pressure pB is preferably also dynamically changing over time.
As explained above, the buffer gas pressure pB for the pressure packing 14 has to be higher than the vent pressure pV in the pressure packing 14. The vent pressure pV is usually measured in the vent line 25 and is used as pilot pressure for setting a pressure regulator for the buffer gas BG. In case of a dynamically changing buffer gas pressure pB, “setting” means control of the buffer gas pressure pB in response to the vent pressure pV.
The pressure in the vent line 25 is however affected by the flow of gas through the vent line 25 that causes a pressure drop along the vent line 25. Therefore, a misreading occurs, if the pressure in the vent line 25 is sensed and used for setting (controlling) the buffer gas pressure pB.
As is well-known, the main determinant of the pressure drop is the gas velocity through the vent line 25, whereas the pressure drop increases with increasing gas velocity. As the leakage flow through the vent line 25 increases over time due to wear in the pressure packing 14, the pressure drop increases uncontrollably over time. Consequently, when the buffer gas pressure pB is controlled with the sensed pressure in the vent line 25, the buffer gas pressure pB, that is set in response to the pressure in the vent line 25, decreases over time. This can cause the pressure difference (pB−pV) to decrease which will reduce the ability of the buffer gas barrier 18 in the pressure packing 14 to stop and contain the leaked process gas PG. The buffer gas pressure pB might even fall below the vent pressure pV, which would result in backflow of process gas PG into the buffer gas feeding line 20 and also increased leakage of process gas PG through the pressure packing 14 into the distance piece 13 or crankcase 7.
Therefore, according to the invention, the pressure in the vent line 25 is not used as pilot pressure for setting (controlling) the buffer gas pressure pB, e.g. by means of a pressure regulator 37 for the buffer gas BG. Instead, an additional sensing line 35 is provided in the pressure packing 14, as is shown in
By sensing the pressure in the sensing line 35, for example using a pressure sensor 36, it is possible to detect the vent pressure pV. If the pressure in the sensing line 35 (that corresponds to the vent pressure pV) is used as pilot pressure for a pressure regulator 37 for setting (controlling) the buffer gas pressure pB it is ensured that the buffer gas pressure pB is always kept sufficiently above the vent pressure pV, even in case of a deteriorating pressure packing 14.
In the embodiment of
A differential pressure control valve could be used as pressure regulator 37. A differential pressure control valve ensures a constant differential pressure in a line with variable flow. The differential pressure control valve has a pilot pressure input and allows to set a desired differential pressure with respect to the pilot pressure. In this case, the sensing line 35 could be connected to the pilot pressure input of the differential pressure control valve and the vent pressure pV in the sensing line 35 would be the pilot pressure for the differential pressure control valve. The sensing line 35 would terminate in the differential pressure control valve, ensuring again a static pressure in the sensing line 35. The differential pressure control valve would be arranged in the buffer gas feeding line 20 to control the buffer gas pressure pB with a set pressure offset (differential pressure) to the pilot pressure (vent pressure pV).
The buffer gas BG for the pressure packing 14 is preferably provided by a purge panel 40, as indicated in
The sensing line 35 is preferably arranged in an upper (in direction of gravity) part of the pressure packing 14. This, together with the fact that the sensing line 35 is a static line without gas flow, reduces or even eliminates the amount of lubricant oil that can be carried with sensing line 35. Therefore, no liquid gas separator is usually required in the sensing line 35 upstream of the purge panel 40, which reduces the costs of the system.
The purge panel 40 has a sensing line inlet 43 for connecting the sensing line 35 to the purge panel 40. The sensing line 35 extends from the sensing line inlet 43 into the purge panel 40. The end of the sensing line 35 in the purge panel 40 is closed, so that there is no gas flow in the sensing line 35 when connected to the purge panel 40. The purge panel 40 has a buffer gas outlet 44, to which the buffer gas feeding line 20 is connected in use of the purge panel 40. The buffer gas inlet 41 and the buffer gas outlet 44 are connected in the purge panel 40 by a gas line 46. In the gas line 46 a pressure regulator 37 is provided, in the example of
In this embodiment, the sensing line 35 is connected to a pilot input 45 of the differential pressure control valve at which the sensing line 35 terminates. The differential pressure, which is preferably preset, between the pressure at the pilot input 45 and the output pressure of the differential pressure control valve (the buffer gas pressure pB) is set by the differential pressure control valve. Hence, the buffer gas pressure pB is offset from the pilot pressure (vent pressure pV) by the preset differential pressure and follows the vent pressure pV in the sense line 35.
When the purge panel 40 supplies more than one pressure packing 14 with buffer gas BG, in each case under control of a vent pressure pV in a sensing line 35 of the respective pressure packing, then the purge panel 40 could also be equipped with more than one pressure regulator 37. In this case, there would be a sensing line inlet 43 for each pressure regulator for connecting the respective sensing line 35 to the purge panel 40. There would also be a buffer gas output connector 44 for each pressure regulator 37 for connecting the respective buffer gas feeding line 20 to the purge panel 40.
The purge panel 40 could also be equipped with additional instrumentation, as will be described with reference to
The buffer gas BG is fed into the purge panel 40 via buffer gas inlet 41, to which a buffer gas supply line 42, connected on the other end to a buffer gas supply 38, is connected when the purge panel 40 is in use. In the purge panel 40, the buffer gas inlet 41 is connected to a gas line 46.
In the gas line 46 an isolation valve 50 is arranged downstream of the buffer gas inlet 41. If an operator wants to perform a routine maintenance operation of the purge panel 40 and isolates the purge panel 40 from the buffer gas supply via the isolation valve 50, the purge panel 40 will remain pressurized and pose a hazard when the operator tries to open a component which is under pressure. Therefore, preferably an isolation valve 50 with downstream vent is used, which automatically depressurizes the panel as soon as the isolation valve 50 is switched into closed position. Such an isolation valve 50 shuts off the gas line 46 upstream of the isolation valve 50 when in closed position. But, when in closed position, the isolation valve 50 opens a vent port on the isolation valve 50 that is connected to the gas line 50 downstream of the isolation valve 50. Hence, the gas line 46 downstream of the isolation valve 50 is depressurized via the vent port when the isolation valve 50 is closed. In the embodiment of
In the gas line 46, preferably downstream of the isolation valve 50 and upstream of further instrumentation, there can also be provided a filter 52, for filtering the buffer gas BG fed into the purge panel 40.
In the inlet section of the gas line 46, there can also be provided a first pressure control valve 53. The gas pressure of the buffer gas BG fed into the purge panel 40 could be varying for different reasons. It is therefore advantageous to set a specified gas pressure in the gas line 46 in the purge panel 40 via the first pressure control valve 53.
Downstream of the first pressure control valve 53 the gas line 46 is fed to the pressure regulator 37 for setting the desired buffer gas pressure as explained above.
In the embodiment of
There can however also be more second gas lines 46a be provided in a purge panel 40, with each second gas line 46a being equipped with its own second pressure control valve 53a. Each second gas line 46a can be connected to a number of buffer gas outlets 47a, 47b.
In the embodiment of
The purge panel 40 can also be equipped with a pressure relief valve 57 that is connected to the gas line 46 downstream of the pressure regulator 37, as in
A pressure relief valve 57 could also open into an overpressure line 58 in the purge panel 40 which in turn could be connected to an overpressure outlet 59, that could open into atmosphere. This is especially preferred when the purge panel 40 is provided with a purge panel enclosure 48.
Furthermore, some monitoring instrumentation can be provided in the purge panel 40 at certain locations. For example, a pressure indicator 51 could be used to display the acting pressure at certain locations in the gas line 46 and/or a second gas line 46a. A flow indicator 56 could be used to display the actual buffer gas flow through certain parts of the gas line 46 and/or a second gas line 46a.
In case of a purge panel enclosure 48 it is advantageous when the purge panel enclosure 48 is open or transparent in the region of a monitoring instrument so that the monitoring instrument is visible from outside. To this end a door of the purge panel enclosure 48 could partly be transparent.
The purge panel 40 can be designed to provide any required number of buffer gas outlets 44, 44a. Each buffer gas outlets 44, 44a could be connected to a separate pressure regulator 37, for allowing to set the buffer gas pressure pB at each buffer gas outlets 44, 44a separately. Some of the buffer gas outlets 44, 44a could however also be connected to a common pressure regulator 37 (as in
A valve could also be provided upstream of a certain buffer gas outlet 44, 44a, 47a, 47b to shut off this buffer gas outlet 44, 44a, 47a, 47b in case it is not needed.
If the purge panel 40 is arranged in an enclosure 48, it is advantageous for safety reasons to avoid hazardous process gas PG to accumulate in the enclosure 48 in case of malfunction. In operation, the sensing line 35 is filled with process gas PG mixed with some buffer gas BG. Theoretically, the sensing line 35 is gas-tight, but in reality, there is always the possibility of an accidental leakage in the enclosure 48 of the purge panel 40 and the possibility of fugitive leaks and accumulation of process gas PG in the enclosure cannot be excluded, which is a potential hazard. To avoid accumulation of process gas PG in the enclosure 48, a pneumatic booster relay 54 could be used. Such a configuration is shown in
A pneumatic booster relay is a known pneumatic device that regulates the pressure of a stream of gas based on a pilot pressure. According to a known embodiment, a pneumatic booster relay 54 has four ports, a supply port 54a, an outlet port 54b, a pilot port 54c and an exhaust port 54d. When a pilot pressure is applied to the pilot port 54c, the main valve assembly of the pneumatic booster relay 54 opens to allow flow from the supply port 54a to the outlet port 54b. When the sensing assembly of the pneumatic booster relay 54 detects that the outlet pressure at the outlet port 54b is equal to the pilot pressure, the main valve moves to a rest position in which the outlet port 54b and the exhaust port 54d are blocked (not connected to the any other port) and will remain in this position until there is a change in the pilot pressure or outlet pressure. If the sensing assembly detects that the outlet pressure is higher than the pilot pressure, the exhaust port 54d opens to vent the excess pressure, for example into an exhaust line or into the surroundings. If the sensing assembly detects that the outlet pressure is lower than the pilot pressure, the main valve opens to connect the supply port 54a to the outlet port 54b for recharging the system to the pilot pressure. In that way, the output pressure at the output port 54b corresponds to the pilot pressure at the pilot port 54a.
When the pneumatic booster relay 54 is arranged outside of the enclosure 48 of the purge panel 40 and the sensing line 35 is connected to the pilot port 54c of the pneumatic booster relay 54, it can be ensured that no process gas PG enters the enclosure 48, as the pilot port 54c of the pneumatic booster relay 54 cannot be connected to the output port 54b of the pneumatic booster relay 54. The supply port 54a of the pneumatic booster relay 54 is connected to the gas line 46 of the purge panel 40 so that buffer gas is supplied to the pneumatic booster relay 54. The sensing line 35 would in this embodiment not be connected directly to the pilot input 45 of the differential regulator 37 but to the pilot port 54c of the pneumatic booster relay 54 and would terminate there. Hence, the pilot pressure of the pneumatic booster relay 54 corresponds again to the vent pressure pV in the sensing line 35. This means that the output pressure of the buffer gas at the output port 54b of the pneumatic booster relay 54 corresponds also to the vent pressure pV. The output port 54b of the pneumatic booster relay 54 is therefore connected to the sensing line inlet 43 and further to the pilot input 45 of the differential regulator 37 to set the pilot pressure for the pressure regulator 37. As a result, the process gas PG contained in sensing line 35 is entirely kept outside of the enclosure 48 thereby preventing any leakage of process gas PG into the enclosure 48 even in case of malfunction of any component in the enclosure 48.
In the embodiment of
In a further advantageous embodiment of a purge panel 40 provisions can be made on the purge panel 40 to allow integration of digital measurement instruments 60, like digital pressure or flow transducer. To this end certain connectors 61 could be provided at the purge panel 40 at certain locations which allow connection of such digital measurement instruments 60. Usage of digital measurement instruments allow integration of a purge panel 40 in a digital control of the purge panel 40 or the reciprocating piston compressor 1.
In
It would be especially advantageous to arrange all analogue instrumentation and piping on a front side of a purge panel 40 and to provide the connectors for the digital measurement instruments at the back side of the purge panel 40. This would allow easy and safe separation of the analogue and digital instrumentation. Furthermore, the user of a purge panel 40 could decide if and which (type, manufacturer) digital measurement instruments he wants to use.
The minimum configuration of a purge panel 40 is shown in