Near Intersection of I-35 & I-90 Southern Mn. | OettingAgService - 11/24/2018 14:25
Getting this alarm. Any idea if it's a cause for concern? The operator tells me the display still shows it's applying the correct rate. Is that shown correct rate reliable while this alarm is active?
I've got some relevant info here: https://support.agleader.com/kbp/index.php?View=entry&EntryID=2059 but it doesn't go too in-depth.
You are wise to question the rate. I'm making some assumptions about your system but the injection systems I've had and worked on (Raven) do NOT directly measure the flow of the injected product. They have a shaft sensor that watches the rotation of the injection pump. Since the pump is a positive displacement pump the output should be directly related to the shaft rotation. The pulses produced by the shaft sensor utilize a calibration number to convert the readings into meaningful units of volume in this case ounces. This is under the ASSUMPTION that the pump is operating properly. If the pump is not pumping properly the displayed rate may appear to be correct when it is not.
Let's say that the inlet to the pump happened to get restricted due to an obstruction on its way from the tank to the pump. This obstruction might be a kinked line, some debris in the tank or other causes. If so, the pump may not be producing the output for each stroke that would normally be expected. The displayed rate (based on the shaft sensor) could still show the proper rate since the pump may be turning the correct RPM.
In order to alert the operator of such a situation, a vacuum sensor is also used. The idea of the vacuum sensor is to alert the operator that the pump is drawing excessive vacuum possibly due to such an obstruction. I believe this is what is happening in your case. This is why the Ag Leader instructions suggest checking the three-way valve, any strainers or lines to the pump. There may or may not be a real problem (possibly the vacuum sensor is falsely reporting a problem) but it is wise to check it.
There is also a flow sensor on the pump. The purpose of this flow sensor is to warn the operator if the pump is not pumping or only one piston is pumping. The pump is a two cylinder design. There is a passageway between the two cylinders. There is a sensor on this passageway. When the pump is operating properly, the flow in this passageway should go back and forth with each stroke. This flow is detected by a sensor which can be observed by watching the red LED on the sensor. The red LED should go ON/OFF with each stroke. This information is also sent to the display so it can warn the operator of such a situation. With a Raven display this warning may be a message to "Check Flow", with the Ag Leader display a message warning about a discrepancy between the analog (flow sensor) and digital (shaft sensor) exists.
This is the alarm that should sound with an empty tank.
When injection systems are installed on sprayers, a single column visual flow monitor (Redball/Wilger) can be installed on the output line. This always the operator to get a visual confirmation that the product is being injected. Unfortunately this is not possible when injecting N-Serv into NH3.
Edited by tedbear 11/25/2018 07:28
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Ag Leader Direct Inject, injection pump inlet restriction
