How Does an Electronic Pump Stroke Counter Work?
Posted on Feb 23, 2017 by Kathy DeGlandon
Electronic Pump Stroke Counters are a vital part to any drilling rig operation. When a mud pump is in operation, the driller must know how much mud is flowing down hole in order to keep the operation running at peak efficiency. Pump stroke counters assist the driller by measuring the mud pump’s strokes per minute and total strokes. So, how does a pump stroke counter tally the mud pump’s strokes
Electronic Pump Stroke Counters are a vital part to any drilling rig operation. When a mud pump is in operation, the driller must know how much mud is flowing down hole in order to keep the operation running at peak efficiency. Pump stroke counters assist the driller by measuring the mud pump’s strokes per minute and total strokes. So, how does a pump stroke counter tally the mud pump’s strokes, and why it is important? In order to understand that, you’ll need to know some basic information about mud pumps.
HOW DOES A MUD PUMP WORK?
Knowing how a mud pump functions is important in understanding the role a pump stroke counter plays in rig operations. Mud pumps act as the heart of the drilling rig, similar to how our heart works. Just as our heart circulates blood throughout our bodies, a mud pump circulates essential drilling mud down the hole and back up to the surface. Mud tanks house drilling mud, and a mud pump draws the fluid from the mud pump. A piston draws mud in on the backstroke through the open intake valve and pushes mud through the discharge valve and sends it towards the rig. By circulating fluid, the mud pump ensures that the drill bit is cool and lubricated and that cuttings are flushed from the hole. The two main kinds of pumps used are duplex and triplex pumps, where the duplex pump has two pistons and the triplex pump has three. Whether the rig is using a duplex or triplex pump, it is important to know how many strokes per second the pistons are moving. The driller monitors strokes per minute to determine how much costly, yet essential, mud is being pumped into the system with the use of a mud pump stroke counter system. Now, that you know about mud pumps, you’ll need to know what’s in a stroke counter system.
WHAT’S IN A ELECTRONIC MUD PUMP STROKE COUNTER SYSTEM?
A Electronic Stroke Counter system consists of a stainless steel stroke counter, micro limit switches, cable and junction box.
Stroke Counter — The stroke counter stainless steel box is mounted on the driller’s console and is either square or rectangular in shape, depending on the number of pumps it is monitoring. Stroke counters will show strokes per minute and total strokes, and when a particular mud pump is operating the strokes/minute and total strokes will be displayed. Power is supplied by a 3.6 volt lithium battery, and the counter contains a crystal-controlled real time clock with 100 parts per million accuracy or better. Each counter is mounted to the console with 1/4” stainless steel hex head bolts, lock washers and nuts.
Micro Limit Switch — The micro switch is connected to a c clamp near the mud pump piston. The micro switch stainless steel rod (sometimes called a whisker) sticks out in the piston housing near the piston. As the piston passes the rod, it moves the rod and the switch sends an electronic signal back to the counter. The counter increases by one each time the piston moves the rod, counting the mud pump’s strokes. The switch’s signal is then transmitted to the stroke counter. These micro switches are built to stand up to demanding outdoor conditions. They can withstand shock, equipment vibration, extreme temperatures, water and dust.
Cable and Junction Box – A cable is connected to the back of the pump stroke counter and then to the junction box. From the junction box, the cables travel to the limit switches.
HOW DO ELECTRONIC PUMP STROKE COUNTERS WORK?
Pump Stroke Counters are like a blood pressure machine. Each time our heart pumps, a blood pressure machine reads our systolic and diastolic blood pressure by way of our pulse. A mud pump stroke counter functions in much the same way. Just as a blood pressure machine detects our pulse so too does a limit switch rod detect the movement of the piston. When the stainless steel rod is moved, the micro limit switch detects the movement. The signal is sensed as a contact closure, and it is transmitted to the stroke counter where the contact closure is converted to a logic pulse. The pulse feeds two separate circuits. The total strokes circuit reads and displays the closures one at a time, totaling them up to reveal the total strokes in the LED window. The second pulse is sent along a separate circuit which is a rate circuit. This rate circuit will average the closures against the real time clock. The result is displayed as the total strokes per minute.
Benefits of Using Digital, Electric Pump Stroke Counters
• Self-contained, battery powered system, not external power required
• Intrinsically safe design, low energy
• Easy-to-maintain stainless steel case, durable in harsh environments
• Easy-to-read, large LCD display to view at a distance
• Plug-and-go installation, no calibration needed
• Vibration resistant, for use on land or offshore drilling
• Study C-Clamp holds switch in position for continuous operation
• Adjustable and bendable stainless steel rod on switch can be mounted in any position
Pump stroke counters are essential to drilling rig operations because they measure the efficiency of mud pumps. Knowing strokes per minute and total strokes of the pistons helps the driller to determine if the correct amount of mud is going down hole. Having this information aids in running a drilling rig at peak efficiency, assists in extending drill bit life, and avoids costly overuse of drilling rig mud. Unsure which pump stroke counter is right for your application? Give our friendly, knowledgeable staff a call or email. We’ll keep you turning right.
References
How Does a Mud Pump Work? https://en.wikipedia.org/wiki/Mud_pump
Basic Knowledge of Mud Pumps http://www.drillingformulas.com/basic-knowledge-of-mud-pumps-vdo-training/
Honeywell Limit Switch https://sensing.honeywell.com/honeywell-sensors-switches-oil-rig-application-note-000756-4-en.pdf
Mud Pump Image Courtesy of https://commons.wikimedia.org/wiki/File%3AMud_pumps_and_pits.jpg
